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• Synthesis of mixed ligand copper(I) complexes. • Single-crystal X-ray diffraction reveals distorted tetrahedron geometry around the copper. • All copper(I) complexes are found to be efficient catalyst for C-C and C-N coupling reactions. • Substituent group on ligand shows marked effect on catalytic performance of the complexes. A series of three copper(I) complexes with formula [Cu(L 1-3)(PPh 3) 2 ]PF 6 has been synthesized and characterized; where L 1 = 4-(benzylideneamino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, L 2 = ((4-methoxy benzylidene) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one and L 3 = 1,5-dimethyl-4-((4-nitrobenzylidene)amino)-2-phenyl-1,2-dihydro-3H-pyrazol-3-one and PPh 3 = triphenylphosphine. The complexes were characterized through elemental analysis, FT-IR, 1H NMR, UV-Visible and thermal analysis. Furthermore, the crystal structure of complex 3 was determined by single-crystal X-ray diffraction, revealing a distorted tetrahedral geometry around the copper center with N and O donor atoms coordinated present in the ligand frame. These copper complexes have been found to serve as efficient catalysts for C-C and C-N coupling reactions. The role of electron donating and electron withdrawing substituents in the ligand of the copper(I) catalyst was investigated in relation to their impact on C-C and C-N coupling reactions. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of Cu(II), Co(II) and Ni(II) complexes of novel Schiff base ligand. • Computational calculations for the proposed structures were conducted using DFT. • The ligand and Co(II) complex are promising for developing NLO materials. • Molecular docking reveals a high binding affinity of ligand and Co(II) complex. • Cumulative deviation and fluctuation were below 2Å with many intermolecular interactions. Novel Schiff base metal complexes diaqua(4-chloro-2-{[(4-(dimethylamino)phenyl)methylene]amino}phenolato)M(II) ion, (M = copper/cobalt/nickel) have been synthesized using the ligand 4-chloro-2-((4-(dimethylamino)benzylidene)amino)phenol, which was prepared by reacting 2-amino-4-chlorophenol with 4-(dimethylamino)benzaldehyde in a molar ratio of 1:1. The synthesized compounds were characterized based on elemental analysis, FTIR, UV–vis., 1H and 13C NMR, powder XRD, mass spectrometry and magnetic studies. Spectroscopic investigations demonstrated that the metal atom coordinates to a bidentate Schiff base ligand via the azomethine nitrogen and phenolic oxygen. The appropriate molecular geometry for each metal complex has been proposed through the analysis of spectroscopic and analytical data, Specifically, tetrahedral geometry has been proposed for Co(II), Ni(II), and square planar geometry for Cu(II) complex. Theoretical calculations employing Density Functional Theory (DFT) validated the experimental results, elucidating optimized geometries, frontier molecular orbitals, natural bond orbital distributions, molecular electrostatic potentials, non-linear optical properties, IR vibrational modes, and UV absorbance profiles. Additionally, the compounds' biological efficacy was validated through molecular docking against receptors for Gram(+ve) bacteria, Bacillus subtilis (PDB ID: 5H67), Staphylococcus aureus (PDB ID: 3TY7) and Gram(-ve) bacteria, Escherichia coli (PDB ID: 3T88), Proteus vulgaris (PDB ID: 5I39). The outcome revealed that Co(II) complex exhibited highest binding energy with Escherichia coli and Bacillus subtilis while the ligand with Proteus vulgaris (5I39) and Staphylococcus aureus (3TY7). Further the study was extended to the MD Simulation in water for 100 ns to evaluate the binding affinities and its stabilities by analyzing the deviation, fluctuations, and intermolecular interactions. The research presented here showcase the potential of employing a Schiff base ligand and its Co(II) complex in the synthesis of novel, highly potent antibacterial agents to combat emerging diseases, which holds considerable importance in the field of pharmaceutical science—however, in-vitro studies are needed to validate the results. [Display omitted] [ABSTRACT FROM AUTHOR]

• Solvent tuning yields copper complexes with variable nuclearity and geometries. • Solid-state structures stabilized by diverse intermolecular forces emphasize non-covalent interactions. • Both complexes show dominant antiferromagnetic interactions between Cu(II) centers via DFT. • Theoretical analysis unveils strong antiferromagnetic interactions within trimeric units. • Magnetic exchange coupling constants (J values) accurately predict magnetic properties. The solvent tuning technique has been employed to synthesize two new copper complexes [Cu 3 (L)(NO 3) 2 (DMSO) 4 ] (1) and [Cu 6 (L) 2 (NO 3) 2 (DMF) 4 (H 2 O) 2 (µ-HCOO) 2 ] (2) which display variable nuclearity and coordination geometries. The synthesized complexes further characterized by using spectroscopic, single crystal and powder X-ray diffraction techniques. Supramolecular assembly of the complexes in the solid state is stabilized by a range of intermolecular interactions including O-H⋅⋅⋅O, C-H⋅⋅⋅O, π⋅⋅⋅π and C-H⋅⋅⋅π. Magnetic susceptibility measurements (χT vs T curves) over a wide range of temperature indicate dominant antiferromagnetic interactions between the Cu(II) centres in both complexes, while DFT calculations reveal the nature and amplitude of the main magnetic interactions. Theoretical study further shows strong antiferromagnetic interactions inside the trimeric units of both complexes as well as both weak ferro- and antiferromagnetic interactions among the trimers. The so-obtained J values have been employed to fit the χT vs T curves, using simplified spin models which correctly reproduce the main features of the experimental curves. Thus, this combined experimental and theoretical study provides insight into the magnetic structure of the copper complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

• In the pursuit of innovation, four distinct mono Azo dyes D 1 -D 4 were synthesized. • Subsequently, these Azo ligands are transformed into copper Azo complexes, namely (D 1 CuC-D 4 CuC). • These Azo dyes and their copper complexes were characterized using FTIR, 1H NMR, 13C NMR, and UV–visible spectroscopy. • Protein-ligand docking approach was used for binding affinity to an anti-oxidant receptor protein (PDB ID: 2HCK) which showed excellent binding interactions. • The findings from an in vitro antioxidant activity using the DPPH scavenging method exhibited that complexes are more active than ligands. In the pursuit of innovation, four distinct mono Azo dyes D 1 -D 4 were synthesized. These dyes were crafted through a coupling reaction involving 1-naphthol, resorcinol and salicylic acid with diazonium salts derived from a diverse array of aromatic amines, including aniline and sulphanilic acid. Subsequently, they are transformed into copper Azo complexes, namely (D 1 CuC-D 4 CuC). The structural underpinnings of these mono Azo dyes and their corresponding copper complexes were unveiled using an arsenal of analytical techniques: FTIR, 1H NMR, 13C NMR, and UV-visible spectroscopy which unequivocally confirmed their synthesis. A computational protein-ligand docking approach was used to assess the binding affinity of ligands and metal complexes to an anti-oxidant receptor protein (PDB ID: 2HCK) which showed excellent binding interactions. The findings from an in vitro antioxidant activity using the DPPH scavenging method exhibited: Complexes > Ligands. As an antioxidant agent, the synthesized compounds may prove to be a great therapeutic option. This research introduces a novel approach by utilizing Azo dyes as ligands, leveraging their exceptional electronic tunability and stability to form innovative copper complexes. Their pharmacological applications will be explored, potentially yielding drugs with improved efficacy and selectivity. [Display omitted] [ABSTRACT FROM AUTHOR]

• A pair of chiral cuprous complexes was synthesized, showing good mirror symmetry of the crystal structures, circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. • Multi-stimuli CD responses to poor solvent, ultraviolet irradiation time, H 2 O 2 as well as temperature with corresponding mechanisms discovered for the first time in the field of cuprous compounds. • UV enhanced emission in solution with mechanism studied. • Circularly polarized luminescence (CPL) discovered with g lum being ±5.3 × 10−3. • TD-DFT calculations revealed the origin of the luminescence. A pair of chiral cuprous complexes, R/S-[Cu 2 (BINAP) 2 (3-CN-Py)(CH 3 CN) 2 ](PF 6) 2 ·2CH 2 Cl 2 (BINAP = 1,1′-binaphthyl-2,2′-diphenyl phosphine, 3-CN-Py = 3-cyanopyridine) (abbreviated as R/S-Cu2), was synthesized. The crystal structures, circular dichroism (CD) and circularly polarized luminescence (CPL) spectra of R/S-Cu2 showed good mirror symmetry. Multi-stimuli CD responses of R/S-Cu2 in DMSO solution to water as poor solvent, ultraviolet irradiation time, H 2 O 2 as well as temperature and corresponding mechanisms were discovered for the first time in the field of cuprous compounds. The solid state luminescence of R/S-Cu2 may be ascribed to (M + L)L'CT transition according to TD-DFT calculations. The emission of R-Cu2, taken as an example, in DMSO solution showed enhancement upon short time UV irradiation, which may be due to the removal of the luminescence quencher of oxygen. The CPL properties of R/S-Cu2 in solution before and after short time UV irradiation were investigated (g lum = ±5.3 × 10−3). This work provides a new research strategy and opens up a prospect for the multiple applications of chiral cuprous materials. A pair of chiral multi-functional cuprous complexes shows multi-stimuli CD responses, UV enhanced emission in solution and circularly polarized luminescence with corresponding mechanisms' studies accompanied by TD-DFT calculations. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of new Schiff base copper complex was presented. • Assessing intermolecular interaction was carried out. • Hirshfeld surface and enrichment ratio studies were performed. • DFT computational studies were carried out. • Molecular docking studies were reported. Bi-dentate N, O mononuclear Cu(II) complex [Cu(C 14 H 12 BrNOS) 2 ] was synthesized and characterized by FTIR spectroscopy. Single-crystal X-ray diffraction studies reveal the Cu(II) complex crystallizes in a monoclinic P 2 1 / c space group. The mononuclear copper complex comprises four coordinates with perfect square planar geometry (τ 4 =0). The copper complex shows C H···Br and C H···C interaction, respectively, enables the formation of multi-dimensional supramolecular architecture. The nature of the above intermolecular interactions is quantified by Hirshfeld surface analysis. The strength of the interaction and 3D topology of crystal packing are visualized through an energy framework. Further, the physical nature of intramolecular interactions is assessed by QTAIM, the NCI index model. The theoretical approach based on DFT was employed to evaluate the optimized electronic structure, HOMO-LUMO, energy gap, molecular properties and global parameters. The copper complex exhibits good antibacterial activity against S. aureus. The molecular docking of the copper complex shows good binding affinity towards S. aureus TyrRS. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new intelligent semi-salamo-type copper complex (CuL1) was synthesized to consume excess glutathione (GSH) in tumor cells for enhanced CDT. • CuL1 can be degraded GSH and produced highly toxic •OH, which further increased the efficacy of CDT. • The semi-salamo-type complex can be utilized to create more intelligent metal-based anticancer drugs and improve the effectiveness of tumor CDT. Due to its high selectivity, chemokinetic therapy (CDT), which uses Fenton catalyst to kill cancer cells by converting intracellular H 2 O 2 into highly toxic hydroxyl radicals (·OH), has shown potential application in the treatment of tumors. Nevertheless, the presence of overexpressed glutathione (GSH) in tumor cells limits the lethal effect of this treatment on tumors. Herein, an intelligent semi-salamo-type copper complex (CuL1) was synthesized to consume excess glutathione (GSH) in tumor cells for enhanced CDT. Research on the crystal structure of CuL1 indicates that the formed complex self-assembles through intermolecular hydrogen bonding interactions, resulting in a three-dimensional supramolecular shape that can be infinitely stretched inward. After being internalized by tumor cells, CuL1 can be degraded and reduced by GSH, resulting in the generation of high concentrations of Cu (I). The subsequent Fenton-like reaction resulted in excessive Cu (I) ions binding with H 2 O 2 to produce highly toxic ·OH, increasing the efficacy of CDT. Our findings can be utilized to create more intelligent metal-based anticancer drugs and improve the effectiveness of tumor CDT. A intelligent semi-salamo-type copper complex (CuL1) was prepared and characterized. Such CuL1 could enhance the specificity, high efficiency and biosecurity of CDT in inhibition of cancer cell growth. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two thiosemicarbazone-based Cu complexes with proapoptotic activity were synthesized. • Complex 1 bound to DNA via an intercalation mode and arrested cell cycle in S phase. • Complex 1 enhanced ROS generation, caused mitochondria dysfunction and ATP depletion. The copper ion and thiosemicarbazone group are well known for their biological activity, endowing the thiosemicarbazone copper complexes with medicinal perspectives. In this work, two copper complexes [Cu(qcpt)(PPh 3) 2 Br]·2CH 3 CN (1) and [Cu 2 (qcapt)(Ac) 2 (CH 3 O)] (2) derived from the bioactive quinoline-thiosemicarbazone conjugate (qcpt = quinoline-2- carboxaldehyde-4-pyridine-3-thiosemicarbazone; qcapt = quinoline-2-carboxaldehyde acid-4- pyridine-3-thiosemicarbazone) were rationally synthesized and characterized by single crystal X-ray diffraction, Infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and etc. In vitro antitumor studies suggested that complexes 1 and 2 showed effective anti-proliferative activity against malignant tumor cells, especially for complex 1 that exhibited the most sensitive against SMMC7721 cells (human liver carcinoma cell lines). Further, mechanistic studies showed that complex 1 could readily enter the cells, block the cell cycle, cause mitochondrial dysfunction and ATP depletion, enhance the levels of intracellular reactive oxygen species (ROS), and eventually trigger cell death via apoptosis. Additionally, complex 1 bound to CT-DNA via an intercalation mode as evidenced by spectroscopic experiments, molecular docking study and cleaved pBR322 DNA efficiently in the presence of H 2 O 2. Copper complex 1 demonstrated most sensitive against SMMC7721 cells. The mechanistic studies elucidated that complex 1 could enter the cells, arrest the cell cycle, elicit ROS overproduction and cause mitochondrial dysfunction accompanied with ATP depletion. Eventually, complex 1 triggered apoptotic tumor cell death. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two Cu(II)-complexes 1 and 2 were synthesized and characterized. • Complexes 1 and 2 can degrade 86.9 % and 97.0% MB in 24 min, respectively. • Both complexes could be used repeatedly for the degradation of MB. • The main reactive species for MB degradation were ·OH and h+. Two Cu(II)-complexes [Cu(Hcpota)(4,4′-bpy)(H 2 O)] n 1 and [Cu(Hcpota)(1,4-bib)(H 2 O)] n 2 based on a semirigid ligand 2-(4-carboxyphenoxy)terephthalic acid (H 3 cpota) were solvothermally prepared and characterized. Complexes 1 and 2 exhibit an unprecedented 2D 4-connected framework with a {44.62} topology, comprising the Cu(II) ion with square pyramidal coordination. The three-dimensional frameworks are constructed by O–H···O hydrogen bonds. Magnetization analyses were conducted and revealed that complexes 1 and 2 have ferromagnetic properties. The photodegradation of Methylene blue dye was studied based on 1 and 2 as photocatalysts. The results indicated that complexes 1 and 2 exhibited remarkable photodegradation efficiencies of 86.9 % and 97.0 % after 24 min, respectively. Furthermore, pseudo-first-order kinetics was assumed for the photocatalytic reaction with a rate constant of 0.052 and 0.109 min−1 for 1 and 2. The impact of factors, including the initial concentration of MB, catalyst dosage, pH value, H 2 O 2 concentration, and temperature on the degradation process of MB was thoroughly examined. The complexes exhibited excellent recyclability and stability as photocatalysts. Trapping experiments and LC-MS studies revealed that the primary active species responsible for the degradation reaction are hydroxyl radicals (·OH) and holes (h+). Two Cu(II)-based complexes synthesized via the solvothermal method have been utilized as catalysts for UV–vis light-induced dye degradation, the introduction of H 2 O 2 significantly enhances the efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two new Cu(II) polymeric complexes supported by a pyridylamide ligand were prepared. • The complexes were characterized by X-ray crystallography and spectroscopic methods. • Hirshfeld analysis was conducted to identify the intermolecular interactions. • Computational studies were performed to understand the electronic structures. In our effort to understand the impact of ligand platforms on the structure diversity and chemical properties of copper clusters, a tripod pyridylamide ligand H3tpmbc was used in this work. Two one-dimensional polymeric Cu(II) complexes [Cu(H 3 tpmbc)Cl 2 ] n (1) and [Cu 2 (H 3 tpmbc)Cl 4 ] n (2) were isolated and characterized. X-ray crystallography analysis showed that both structures have a similar one-dimensional backbone. The main structure difference of the two complexes is the presence of a second Cu(II) site in complex 2. Hirshfeld analysis revealed the presence of interesting C–H⋅⋅⋅ π and π ⋅⋅⋅ π interaction networks in both complexes. Spectroscopic characterization of both complexes and [CuPyCl 2 ] suggests the source of the color difference between the two polymers at the solid state. Computational studies based on the X-ray crystal structures were performed and the results provided a deeper understanding of the electronic structures of the Cu(II) site(s) in both complexes. Thermal gravimetric analysis (TGA) demonstrated that the two complexes have the similar thermal behavior, and this could be attributed to the similar one-dimensional backbone structure. [ABSTRACT FROM AUTHOR]

• Different electronic and steric effects of amine backbone led to linear-type M-Dy-M, one-dimensional (1D) chain and interlayer-type structures of complexes. • Align the magnetic easy axis of lanthanide ions as closely as possible with the direction of M-M facilitating the mitigation of quantum tunneling of magnetization. • Notable hysteresis loops at maximum temperature of 3.5 K, 7.5 K, and 4 K are observed for Cu 2 Dy, Zn 2 Dy and Ni 2 Dy complexes, respectively. Series of 3d-4f heterotrinuclear complexes [ M Dy M ] (M =Zn, Cu, Ni) with formula [Cu 2 (L1) 2 DyCl 2 (H 2 O)]·Cl·MeCN (1), [Cu 2 (L2) 2 DyCl 2 ] n (2), [Cu 2 (L3) 2 DyCl 2 (MeOH) 2 ]·Cl·(MeOH) 3 (3), [Zn 2 (L1) 2 DyCl 2 (H 2 O)]·Cl·MeCN (4) and [Ni 2 (L1) 2 DyCl 3 ]·(CH 2 Cl 2) 2 (5) were constructed by three hexadentate compartment Schiff bases (L1 = N ,N'-bis(3-methoxysalicylidene)-2,2-dimethylpropane-1,3-diamine; L2 = N ,N'-bis(3-methoxysalicylidene)-1,3-propanediamine; L3 = N ,N'-bis(2‑hydroxy-3-methoxybenzylidene)-1,2-phenylenediamine). Different electronic and steric effects of amine backbone lead to linear-type M -Dy- M , one-dimensional (1D) chain and interlayer-type structures of complexes 1 – 5 , respectively. Among these, complexes 1, 4 and 5 were constructed as the M -Dy- M linear-type coordination configuration containing diamagnetic zinc(II) ions and paramagnetic copper(II) ions or nickel(II) ions respectively. Molecular magnetic studies reveal that complexes 1, 4, 5 and chain complex 2 exhibited significant single-molecule magnets (SMMs) behavior and the notable hysteresis loops at maximum temperature of 3.5 K, 3 K, 7.5 K, and 4 K are observed, which are comparable among the outstanding heteronuclear (d/f) SMMs constructed by Schiff base ligands. Series of 3d-4f heterotrinuclear [MDyM] SMMs were constructed, different electronic and steric effects of amine backbone lead to very different structure and displaying significant magnetic relaxation with hysteresis loops at maximum temperature of 3.5 K, 3 K, 7.5 K, and 4 K, respectively, which are comparable among the outstanding heteronuclear (d/f) SMMs constructed by Schiff base ligands. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cu(II) coordination polymer and trinickel EMACs were synthesized and structurally characterized using the unsymmetrical pyrazine-modulated Hppza ligand. • Magnetic interaction parameters for 3 (J = −199.2 cm−1) and 4 (J = −178.0 cm−1) support superexchange pathways along metal cores. • Due to the electron-withdrawing effect of pyrazine, the nickel strings of Hppza are readily reduced, retarding oxidation. • The activities of ligands and their nickel string complexes against various proteins were compared with theoretical calculations, and then the ADME/T properties of molecules were examined. • The interactions occurring in the molecular docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. The unsymmetrical pyrazine-modulated ligand, N-(pyridine-2-yl)pyrazin-2-amine (Hppza) (1), its 1D straight-chain copper (II) coordination polymer [Cu 2 (Hppza) 2 ∙(NO 3) 4 ] n (2) and trinuclear metal string [Ni 3 (µ 3 -ppza) 4 Cl 2 ] (3) and [Ni 3 (µ 3 -ppza) 4 (NCS) 2 ] (4) complexes have been successfully synthesized and structurally characterized. The free ligand Hppza (1) exhibits anti-syn conformation. In an asymmetric unit of 2 , there are two kinds of Cu(II) atoms, both of which have elongated octahedral coordination geometry, and the copper(II) centers are linked by oxygen atoms of one nitrate anion. There are only minor differences in Ni...Ni bond lengths between pyrazine-modulated ligand complexes of [Ni 3 (μ 3 -ppza) 4 × 2 ] (X = Cl− (3), NCS− (4)) and their unmodulated analogs, while the distances between the terminal nickel atoms and the axial ligands 3 and 4 are shorter. The results of magnetic susceptibility measurements showed an antiferromagnetic exchange constant (J) of about J = –199.2 cm–1 for 3 and J = –178.0 cm–1 for 4. The electrochemical properties of nickel strings of Hppza differ significantly from their unmodulated counterparts. The activities of ligands and their metal complexes against various proteins that are AChE (PDB ID: 4M0E), BChE (PDB ID: 5NN0), α-Gly (PDB ID: 1UAS), hCA I (PDB ID: 2CAB), and hCA II (PDB ID: 3DC3) were compared, and then the ADME/T properties of molecules were examined. Afterward, the interactions occurring in the docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. These complexes were inhibitors of BChE, hCA I and II, α-glycosidase and AChE enzymes for complex 3 and 5 with Ki values of 12.65 and 42.95 μM for hCA I, 3.64 and 15.84 μM for hCA II, 5.44 and 50.07 μM for BChE, 15.85 and 4.77 μM for α-glycosidase and 8.58 and 86.24 μM for AChE, respectively. The unsymmetrical pyrazine-modulated ligand, N-(pyridine-2-yl)pyrazin-2-amine (Hppza) (1), its straight chain copper (II) coordination polymer [Cu 2 (Hppza) 2 (NO 3) 4 ] n (2) and trinickel string complexes [Ni 3 (µ 3 -ppza) 4 Cl 2 ] (3) and [Ni 3 (µ 3 -ppza) 4 (NCS) 2 ] (4) have been successfully synthesized and structurally characterized. The activities of ligands and their metal complexes against various proteins were compared with theoretical calculations, and then the ADME/T properties of molecules were examined. Afterward, the interactions occurring in the docking calculation were examined in detail with the Protein-Ligand Interaction Profiler (PLIP) service. [Display omitted] [ABSTRACT FROM AUTHOR]

• New copper(II) complex with O,N,O -quinazolinone Schiff base ligand was synthesized. • The structures of Cu(II) complex and ligand were confirmed by spectroscopic methods. • The single crystal X-ray analysis was performed for both compounds. • Intermolecular interactions were investigated by Hirshfeld surface analysis. • DFT calculations were performed in order to interpret the experimental data. A quinazolinone-based Schiff base ligand 3-[(2‑hydroxy-5-methoxybenzylidene)amino]-2-(2‑hydroxy-5-methoxyphenyl)-2,3-dihydroquinazolin-4-one (L 1) and its new mononuclear copper(II) complex [Cu(L 1)Cl(H 2 O)] (1) were synthesised and fully characterised by various spectroscopic techniques (NMR, FTIR, UV–Vis) and single-crystal X-ray diffraction study. The aspherical model of the crystal structure of the ligand L 1 as well as of the copper(II) complex 1 was refined by the Hirshfeld Atom Refinement method. The crystal structure of the copper(II) complex shows the existence of a substitution disorder at the position of the water molecule, which represents two different complex molecules [Cu(L 1)Cl(H 2 O)] (1a) and [Cu(L 1)Cl] (1b) with different coordination polyhedra around the copper atom. The majority of the mononuclear complex [Cu(L 1)Cl(H 2 O)] (1a) in the crystal structure contains a coordinated water molecule, but the minority in the crystal structure contains a mononuclear complex [Cu(L 1)Cl] (1b) and a water molecule is outside the coordination sphere around the copper atom. The crystal structure of complex 1 showed a penta-coordinated (1a) or tetra-coordinated (1b) Cu atom in the shape of a tetragonal pyramid (1a) or square planar (1b) formed by a chloride atom in the equatorial plane, and a Schiff base bound as an O,N,O -tridentate ligand, and an additional water molecule in the axial position (only 1a). A detailed analysis of the intermolecular interactions was investigated using three-dimensional 3D Hirshfeld surfaces and their associated two-dimensional 2D fingerprint plots. Hirshfeld surface analysis was performed for both crystal structures. Furthermore, theoretical DFT analysis has been performed in order to interpret the experimental data. In order to obtain high quality DFT data, we present here a new basis set B1MH, which is an extension of the LanL2DZ basis with incorporated polarisation and diffusion functions for heavy atoms (C, N, O, Cl and Cu) and added ECPs for Cl and Cu atoms. The presented B1MH basis set allowed us to obtain better theoretical results than those previously published. [ABSTRACT FROM AUTHOR]

• A quinoline-including half-salamo like N 3 O-donor ligand was synthesized. • Differently structural Cu(II) and Ni(II) complexes were synthesized and structurally characterized. • The intermolecular interactions were quantitatively analyzed by hirshfeld surfaces and 2D fingerprint plots. A half-salamo like N 3 O-donor ligand HL was synthesized and used for the construction of Cu(II) and Ni(II) complexes, namely as [Cu(L)(NO 3)] (1) & [Ni 2 (L) 2 (NO 3) 2 ]·2H 2 O (2). The constructed complexes were structurally characterized by X‐ray crystallography technique. The results revealed that the complex 1 is the most common mononuclear species, in which Cu(II) ion is penta-coordinate with twisted square pyramid configuration. Unlike complex 1, the central Ni(II) ions of dinuclear complex 2 are hexa-coordinate possessing slightly distorted octahedron. The final supramolecular structures of the two complexes are stabilized and expanded by noncovalent interactions. In addition, spectral characteristics of the title complexes were examined. The frontier molecular orbitals as well as energy gaps of the complexes were explored by density functional theory calculation. The primary aspects of the ultraviolet absorption spectra were interpreted using time-dependent density functional theory computation. Thorough analysis of the Hirshfeld surfaces quantifies the interactions involved in the crystal structures of the Cu(II) and Ni(II) complexes. Two differently structural metal(II) complexes [Cu(L)(NO 3)] (1) and [Ni 2 (L) 2 (NO 3) 2 ]·2H 2 O (2) containing a half-salamo like N 3 O-donor ligand were successfully synthesized and characterized. The spectral properties of the two complexes were studied. Moreover, the frontier molecular orbitals as well as energy gaps of the complexes were explored by DFT calculation. The Hirshfeld surfaces analyses and 2D fingerprint plots were performed to quantify the interactions involved in the crystal structures of the two complexes. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract A new one-dimensional coordination polymer, [Cu II (L) 2 ][Cu I (bpy)] 2 ·4H 2 O (BUC-20) (H 2 L = cis -1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid, bpy = 4,4-bipyridine), was synthesized solvothermal condition. The crystal structure of BUC-20 was analyzed, and its properties like band energy, water stability, and photocurrent were clarified. BUC-20 exhibited outstanding photocatalytic Cr(VI) performance upon the UV light irradiation under acid condition, which was superior to those of existing photocatalysts. The photocatalytic performance was not influenced by the presence of inorganic ions, which was affirmed by the introduction real surface water to prepare simulated wastewater. BUC-20 exhibited good water stability, and could be used several runs without significant efficiency decrease. Graphical abstract Image 1 Highlights • BUC-20 is a water stable 1D coordination polymer containing mixed-valence CuI/CuII. • BUC-20 displays excellent photocatalytic Cr(VI) reduction under UV light irradiation. • The photocatalytic activity isn't effected by co-existing ions in real surface water. • BUC-20 can be used as efficient photocatalyst for several runs. [ABSTRACT FROM AUTHOR]

• Both HL1 and dinuclear zinc(II) and copper(II) complexes were characterized by X-ray crystallography. • The experimental investigations match with those obtained from TD-DFT calculations. • ESP calculation results confirmed the charge distribution in the molecule and Hirshfeld surface analyses of both complexes were also discussed. • The antibacterial activities manifested that the metal complexes were the best among all the compounds and 2 was superior to 1. Two three-dimensional dinuclear zinc(II) and copper(II) complexes, [Zn 2 (L2) 2 (CH 3 COO) 2 ] (1) and [Cu 2 (L2) 2 (NO 3) 2 ] (2) (HL2 = 1-(2-{[(E)-2-hydroxy-benzyli-dene]amino}phenyl)ethanone oxime), were synthesized by Zn(II) acetate tetrahydrate or Cu(II) nitrate trihydrate with based ligand HL1 (2-(2-phenoxy)-4-methyl-1,2-quinazoline-N3-oxide, H is the deprotonate hydrogen) originally. HL1 and both complexes were characterized by elemental analyses and spectroscopic methods, as well as were confirmed by single-crystal X-ray crystallography. It was revealed that two complexes had 2:2 ligand-to-metal ratios and 1 was hexa-coordinated whereas 2 was penta-coordinated. In the crystal structures, HL1 showed a chain-like, while complexes showed 2-D network stacking constructions, and both complexes further formed a 3-D supramolecular structure. The frontier molecular orbital energy of all compounds was calculated, and TD-DFT calculations were performed to analyze the electronic transitions of HL1 and both complexes. Additionally, the structural optimization and electronic transitions of the molecules were obtained via DFT calculations, molecular electrostatic potential (ESP), Hirshfeld surface analysis (HSA), and two-dimensional fingerprint (2D-FP), supporting X-ray diffraction results with the existence of the H···H and C/O···H bonds as the main interactions in the crystal lattice. Especially, cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) spectroscopy properties of 2 were further analyzed. In terms of biological applications, all compounds were investigated for antibacterial activity, and the results displayed two complexes had the best antibacterial performance than others. The ligand 2-(3-pyrazolyl)-4-methyl-1,2-dihydroquinazoline-N3-oxide (HL1) was synthesized, and two three-dimensional dinuclear Zn(II) and Cu(II) complexes, namely [Zn 2 (L2) 2 (CH 3 COO) 2 ] (1) and [Cu 2 (L2) 2 (NO 3) 2 ] (2) were prepared through complexation reaction between HL1 and the corresponding metal salt. Both HL1 and complexes were characterized by X-ray crystallography, spectroscopic methods such as FT-IR and UV–Vis spectroscopy, as well as Hirshfeld surface analysis and DFT studies. The antimicrobial activities of all compounds were also compared. Cyclic voltammetry (CV) and Electron paramagnetic resonance (EPR) spectroscopy properties of 2 were further analyzed. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis and characterisation of an unprecedented Cu(II) complex of Schiff base derived from taurine and 2‑hydroxy-4-methoxybenzaldehyde. • SCXRD has been used to elucidate crystal structure. • Thermochemistry, atomic electrostatic potentials, and electronic properties were studied using DFT. • Interpretation of Hirshfeld analyses provides information concerning crystal packing and internuclear interactions. • Cu(II) complex can alter the biological capabilities as this trace metal is involved in neurotransmitter synthesis and antioxidant defence. Binuclear Cu(II) complex derived from taurine and 2‑hydroxy-4-methoxybenzaldehyde adduct was synthesised and characterised by X-ray crystallography, spectroscopic, Hirshfeld surface and DFT studies. The complex crystallises in monoclinic system with I 2/a space group. A theoretical study of the Cu (II) complex is performed with unrestricted density functional method at the level of B3LYP/ LANL2DZ/6–311 G (d, p) and a comparison between the experimental and simulated results were conducted. As predicted by the experiment, the computed results support distorted pyramidal geometry at metal centre. Non-covalent interactions primarily H-bonding and π-π stacking close contacts were observed at the intramolecular and intermolecular levels of the complex. An analysis of the FMO parameters reveals less reactivity and stability of complex. A high HOMO energy value and interatomic charge transfer has taken place with the Schiff base ligand. Furthermore, MEP used for predicting reactive sites clearly shows this complex is void of electrophilic reaction site. This complex has been subjected to NBO analysis to determine its hyperconjugation and therefore stability. The NBO analysis revealed the delocalization of charge within the molecule. Based on Hirshfeld surface analysis, there is evidence for a wide range of interactions and a significant contribution from several non-covalent interactions to crystal packing. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract Novel series of ternary complexes of Cu2+ with antiepileptic drug (Gpn) and neurotransmitters (Gly, Asp, Glu, Ser, GABA and Ade) were synthesized. Surface morphology of the complexes and their chemical composition were studied using elemental analysis, SEM and EDX spectrum. Majority of the complexes were non-electrolytes. Molecular weight and purity was confirmed using GC-MS spectrum. Crystallographic parameters were calculated for the complexes from their XRD data using Expo2014 computer program showing monoclinic and orthorhombic crystal systems with space group P 1 21 1 and P 2 21 21. Crystal structural data, UV–Vis spectra and magnetic moment values indicate distorted square planar and pseudo tetrahedral stereochemistry. IR data reveal that Cu2+ is bonded through COOH of the Gpn and NH 2 , COO− of the amino acids. ESR spectra showed d x 2 ‒y 2 ground state for the Cu2+. TGA, DTG, DTA and the suggested decomposition mechanism confirm the proposed structure of the complexes. The complexes [Cu(Gpn)(Asp)(H 2 O)].5H 2 O, [Cu(Gpn)(Ser)Cl] and [Cu(Gpn)(Ade)Cl 2 ].5H 2 O showed superior anticonvulsant activity compared to gabapentin since they significantly reduced the seizure score compared to PTZ group in male Albino mice. Also, the complex [Cu(Gpn)(Asp)(H 2 O)].5H 2 O was the only that markedly prolonged the latency time compared to Gpn group. Highlights • Ternary complexes of Cu2+ with antiepileptic drug (Gpn) and neurotransmitters (Gly, Asp, Glu, Ser, GABA, Ade) were synthesized. • The new compounds were characterized using: UV–Vis., IR, ESR, XRD, EDX, GC-MS spectra, SEM, TGA, DTG and DTA. • Some complexes significantly reduced the seizure score compared to PTZ group in male Albino mice. [ABSTRACT FROM AUTHOR]

Abstract Two thiols fluorescent probes of copper complex based on anthracene derivative was designed. Two compounds (1 and 2) were obtained by the reaction of 9-furaldehyde with benzenesulfonamide and p -nitrobenzenesulfonamide. Then, these compounds were combined with copper ion and two copper complexes (compound 1-Cu 2+ and compound 2-Cu 2+ ) formed. Due to the paramagnetic effect of copper caused fluorescence quenching, two compounds showed strong fluorescence while compound -Cu 2+ almost had no fluorescence. With the additions of cysteine (Cys) and glutathione (GSH), the fluorescence intensities recovered again. While the additions of other amino acids almost did not induce any change. UV–Vis, fluorescence spectra and Circular Dichroism suggested that two copper complexes showed better selectivity and sensitivity to small molecule biothiols among amino acids tested. In addition, cytotoxicity experiments showed that two fluorescence probes have potential application value for biological thiols detection in live cells. Graphical abstract Image 1 Highlights • Two fluorescent probes with anthracene as a fluorescent groups were synthesized. • The probes were capable of distinguishing among Hcy, GSH and Cys. • The interaction of probes to Cys were studied by Circular Dichroism. • Their potential application to bioimaging were also illustrated. [ABSTRACT FROM AUTHOR]

Abstract Cu(II) complexes [Cu(L)(bipy)]ClO 4 (1) and [Cu(L)(phen)]ClO 4 (2) (where HL = 2-[(3-Methylamino-propylimino)-methyl]-phenol, bipy = 2,2′-bipyridine and phen = 1,10-phenanthroline) have been synthesized and characterized by single crystal X-ray diffraction studies, FT-IR spectra, ESI-MS, electronic absorption, and emission spectroscopy. Both the Cu(II) complexes are mononuclear with five coordinated distorted trigonal bipyramidal geometries and the π-conjugated bipy and phen favor the formation of 2D supramolecular structures with CH ... π and π ... π interactions. DFT/TD-DFT calculations were performed using B3LYP, B3PW91 and MPW1PW91 functionals to explain the experimentally observed molecular structure and electronic absorption spectral properties. Complexes are active for catalytic oxidation of 3,5-di- tert -butylcatechol (3,5-DTBC) to 3,5-di- tert -butylquinone (3,5-DTBQ) in presence of molecular oxygen. Interactions of complexes with bovine serum albumins (BSA) and human serum albumins (HSA) have been studied by electronic absorption and emission spectroscopy and the calculated values of binding constants are 6.91 × 105 L mol−1 (1 -BSA), 6.16 × 105 L mol−1 (1 -HSA), 6.57 × 105 L mol−1 (2 -BSA) and 3.80 × 105 L mol−1 (2 -HSA). Electronic absorption and fluorescence spectroscopic studies reveal that interactions of complexes with CT-DNA occur through intercalative binding mode. Graphical abstract 2D supramolecular copper(II) complexes were synthesized and characterized by structure determination and spectroscopic techniques. Results DFT/TD-DFT computation were used to explain electronic absorption spectra of complexes. Spectroscopic studies reveal both the complexes interact with CT-DNA/serum albumins. Both the complexes also show catecholase activity in presence of molecular oxygen. Image 1 Highlights • Two five coordinated copper(II) complexes synthesized and structurally characterized. • Complexes form 2D supramolecular structure with CH ... π and π ... π interactions. • DFT/TD-DFT calculation performed using B3LYP, B3PW91 and MPW1PW91 functionals. • Complexes show catecholase activity. • Spectroscopic studies reveal interaction of complexes with DNA/protein. [ABSTRACT FROM AUTHOR]

Abstract A new complex of Cu(II), the composition Cu(C 3 H 7 N 3 O 4 S)∙H 2 O, the reaction of thiosemicarbazone glyoxylic acid with copper nitrate in an aqueous medium was synthesised. X-ray diffraction analysis established the composition of the complexes was studied by IR, UV electronic absorption and EPR spectroscopy, and thermogravimetry. Thermogravimetry shows five stages of decomposition in the temperature range 90–990°С. The magnetic susceptibility of the complex is studied. The value of μ eff for the complex is 1.76 BM, which is close to the value of one unpaired electron (1.73 BM). The ligand coordinates with the metal atom and consists of monoanionic Cu(C 3 H 7 N 3 O 4 S)∙H 2 O polymeric complex connected by Cu N bonds with neighbouring molecules. The metal centre coordinates with the oxygen of carboxylic, sulfur of thiolic and nitrogen of the azomethine group. The X-ray data and ESR spectra specify a distorted square pyramidal environment around Cu(II) ion. Highlights • A new polynuclear complex was synthesised from Cu(II) with thiosemicarbazone of glyoxylic acid. • The complex characterised by X-ray analysis, FT-IR,UV-VIS and magnetic susceptibility. • The ligand with the metal atom consists of monoanionic polymeric complex. [ABSTRACT FROM AUTHOR]

Abstract In the present work, complex formation equilibria between copper(II) and 1,1,1-trifluoro-4-(2-methoxyphenyl)butan-2,4-dione (1) have been investigated by UV–vis spectroscopy in ethanol/0.01 M NEt 4 NO 3 as an ionic strength adjuster at 25 °C. The composition of the complex in solution was determined using Job's plot and molar ratio method. Four single crystals of copper complexes CuL 2 (DMF) (2), CuL 2 (3), CuL 2 (DMSO) 2 (4) and CuL 2 (DMSO) (5), which include the ligand molecules in the cis - and trans -conformations, respectively, were obtained. The complexes were characterized with FT-IR spectroscopy, elemental analysis, and X-ray crystallography. In the complexes 2 and 5, the copper atoms adopt distorted square pyramidal coordination polyhedra formed by oxygen atoms, whereas the geometry around the copper atom in the complexes 3 and 4 can be described as square planar and square bipyramidal, respectively. Cu O bond lengths were calculated within the density functional theory using two different functionals, viz., BP86 and B3LYP, in combinations with Ahlrichs and Pople basis sets to be compared with each other and with experimentally determined values. Compounds 1 – 4 were tested for their in vitro antimicrobial activity and found active to a variable extent. According to measured minimum inhibitory concentrations (MIC), the title complexes show comparable or higher activity against bacteria and yeast with respect to the free ligand. It was shown that the biological activity is induced by intact complexes and is not resulted from the complex decomposition into copper(II) ions and the free ligand. Graphical abstract Image 1 Highlights • The binding properties of the ligand 1 in solution and in solid were studied. • The DFT calculation for copper complexes were compared with X-Ray crystallography. • The copper(II) complexes are more bioactive than the initial ligand. [ABSTRACT FROM AUTHOR]

Abstract The reactions of three structurally related flexible 4-pyridyl dithioether ligands, 1,2-bis(4-pyridylthio)ethane (Bpyte), 1,3-bis(4-pyridylthio)propane (Bpytp) and 1, 4-bis(4-pyridylthio)butane (Bpytb) with CuI (CuBr and CuSCN) led to form five new complexes: {[Bpyte](CuI 2) 2 } (1), {[Bpytp]CuI 2 } (2), {[Bpytp] 3 (CuBr 2) 3 } (3), {[Bpytp]Cu(SCN) 2 (CH 3 CN)} (4) and {[Bpytb]Cu(SCN) 2 (DMF)} (5), which have been characterized by IR, SEM-EDS (energy dispersive spectrometer), ultraviolet–visible absorption spectrum and thermogravimetric analysis. Single-crystal X-ray analyses showed that compounds 1–5 possess 1-D chain. Furthermore, compounds 2–5 demonstrated good photocatalytic degradation for methyl orange (MO) irradiated by visible light. Highlights • Five 4-pyridyl dithioether based copper(I) coordination compounds were prepared. • Four compounds accelerate MO photodegradation. • They possess potential application in waste water purification. • They are all potential semiconductor materials. [ABSTRACT FROM AUTHOR]

Abstract A new cationic ligand, 1-methyl-3-(methylthio)pyrazin-1-ium iodide (MMTPI), has been designed and synthesized by regioselective alkylation of 2-methylthiopyrazine with MeI. Reaction of this ligand with CuI in a 3:4 molar ratio under mild conditions (MeCN, r.t.) produces new iodocuprate, [Cu 4 I 7 (MMTP) 3 ] n , containing one-dimensional inorganic chains [Cu 4 I 7 3−] n. The latter are constructed from the basket-shaped {[Cu 3 (μ 3 -I)](I) 3 (μ 2 -I) 3 } building blocks, which are linked by tetrahedral Cu atoms through bridging iodine atoms. The UV–Vis diffuse reflectance measurements reveal that the title iodocuprate possesses semiconductor behaviour with the band gap of 1.80 eV. The thermal stability and electronic structure of the iodocuprate are also discussed. Graphical abstract An unprecedented 1-D iodocuprate aggregate, [Cu 4 I 7 3−] n , charge balanced by 1-methyl-3-(methylthio)pyrazin-1-ium cations (MMTP), has been synthesized by the reaction of CuI with MMTP iodide at ambient temperature. The structure of the new iodocuprate has been investigated experimentally and theoretically. Image 1 Highlights • An unprecedented 1-D iodocuprate(I) aggregate, [Cu 4 I 7 3–] n , has been synthesized. • The structure of the iodocuprate has been investigated. • The thermal stability and electronic structure of the iodocuprate are discussed. [ABSTRACT FROM AUTHOR]

Abstract Mononuclear Cu(II), Ni(II) and V(IV) complexes of a bidentate Schiff base ligand derived from 2-hydroxy-1-naphthaldehyde and 2-methoxyethylamine were synthesized and determined by spectroscopic methods. The crystal structures of HL ligand and Cu(II) complex was determined using single crystal X-ray diffraction method. HL Schiff base behaves as a bidentate ligand and coordinates to the metal ions via the nitrogen and oxygen. The obtained data revealed that the Cu(II) center in the complex (1) is coordinated by oxygens and nitrogens of two ligands in a regular square-planar fashion. The electrochemical behavior of the complexes was studied using cyclic voltammetry. The inhibitory activity of ligand and all the obtained complexes were tested in vitro against MKN-45 cancer cell line. It was found that among synthesized complexes, Ni(II) Schiff base complex namely (2), showed strong inhibitory activity against cancer cells, with IC 50 = 6.654 ± 0.449 μg/mL. Graphical abstract Synthesis, spectroscopic, coordination and anticancer activity of Schiff base complexes derived from N, O-bidentate ligand. Image 1 Highlights • New Schiff base complexes from a bidentate Schiff base ligand were synthesized and fully characterized. • In vitro anticancer activity of ligand and complexes was evaluated against the MKN-45 cancer cells. • Results showed promising anticancer activities of prepared compounds. [ABSTRACT FROM AUTHOR]

Abstract Three novel Cu(II) complexes 1 [Cu(L1) 2 ], 2 [Cu(L2) 2 ] and 3 [Cu(L3) 2 ], where L1H = 2-((3,4-dimethylisoxazol-5-ylimino)methyl)-6-tert-butylphenol, L2H = 2-((3,4-dimethylisoxazol-5-ylimino)methyl)-4,6-di-tert-butylphenol and L3H = 2-((3,4-dimethylisoxazol-5-ylimino)methyl)-4,6-dibromophenol were synthesized and characterized by elemental analysis, FT-IR, UV–Visible, 1H NMR, 13C NMR, ESI mass, EPR and magnetic susceptibility studies. Based on spectroscopic and analytical data, a square planar geometry is assigned for all complexes. DNA binding and cleavage studies against calf thymus DNA (CT-DNA) and supercoiled pBR322 DNA respectively revealed an intercalative mode of binding and also cleave pBR322 DNA in an efficient manner. The ligands and their complexes were examined for antimicrobial activity against bacterial species E. coli, B. subtilis and fungal species S. rolfsii and M. phaseolina and found that all the Cu(II) complexes show more activity than the free Schiff base ligands. The antioxidant activity of metal complexes have also been determined using DPPH assay and found that the complexes are found to be good free radical scavengers. Graphical abstract Image 1 Highlights • Isoxazole Schiff bases and their Cu(II) complexes are prepared and characterized. • All the complexes have adopted square planar geometry. • The complexes have shown better inhibitory potential towards tested microorganisms. • DPPH assay proved that complexes are good free radical scavengers. • Complexes act as good DNA intercalating agents and also cleave DNA efficiently. [ABSTRACT FROM AUTHOR]

Abstract Six new copper (II) complexes with dimethylglyoxime and the amino acids tryptophan, glutamate, proline, arginine and valine were prepared and characterized using elemental analysis, molar conductance, melting points, UV–Vis and IR spectroscopy. The compounds prepared are solids, insoluble in water, ethanol and methanol, but soluble in dimethylsulfoxide (DMSO) and dimethylformamide (DMF). The IR study shows that dimethylglyoxime as primary ligand is coordinated to the metal ion in a bidentate manner with NN donor sites of the oxime function. The secondary ligand is coordinated by the carboxylate oxygen and the N atom of the amino acid, with the exception of glutamate, which is coordinated through the N atom of the amine function. Spectroscopic studies show that all the synthesized copper (II) complexes have an octahedral geometry. The electrochemical behavior of these compounds was determined by cyclic voltammetry, which indicated an irreversible oxidation corresponding to Cu(I) → Cu(II). The antimicrobial activity of ligands and their complexes were studied by the agar diffusion technique using DMSO as solvent on different species of pathogenic bacteria (Escherichia coli and Bacillus cereus) and fungi (Candida albicans and Aspergillus niger). It has been found that some of the complexes are antimicrobially active and show higher activity than the free ligand. Metal chelation affects significantly the antimicrobial behavior of the ligands. In addition, these compounds were screened for their in vitro antioxidant properties using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging. The results obtained show that the antioxidant activity is moderate for complexes with tryptophan and glutamate, but the complex with arginine shows a good antioxidant activity in comparison with ascorbic acid as positive control. Highlights • Synthesis of mixed ligand copper (II) complexes with dimethylglyoxime and amino acids. • Spectroscopic techniques are used for characterization. • Electrochemical studies: cyclic voltammetry. • Biological activities: Antibacterial and Antioxidant activities. [ABSTRACT FROM AUTHOR]

Two transition metal complexes containing copper (II) ion, dye methyl red (H-MR) and nitrogen donor ligands β/γ-picoline (β/γ-pic) have been synthesized for the first time using appropriate starting materials in methanol-water (4:1 v/v) as solvent and characterized by spectroscopic methods (UV–Vis, FT-IR) and thermogravimetric analyses. The crystal structures of both complexes have been unambiguously determined by single crystal X-ray analysis as [Cu(MR) 2 (β-pic) 2 ] for 1 and [Cu(MR) 2 (γ-pic) 2 (MeOH) 0.5 (H 2 O) 0.5 ]∙0.5MeOH∙1.5H 2 O for 2 . Whereas in complex 1 Cu(II) coordinated by carboxylate oxygen atoms of two MR and nitrogen atoms of two β-pic molecules adopts an almost ideal square planar geometry, in complex 2 Cu(II) additionally coordinated by methanol/water exhibits a distorted square pyramidal structure. Both complexes are packed in layers stabilized by intermolecular C/O H⋯O hydrogen bonds. DFT calculations provided insight into the existence of the six possible relevant complexes. The relative stabilities are in the order Cu(MR) 2 (γ-pic) 2 (H 2 O) 2w  ≈ Cu(MR) 2 (β-pic) 2 (H 2 O) 1w  > Cu(MR) 2 (γ-pic) 2 (MeOH) 2m  ≈ Cu(MR) 2 (β-pic) 2 (MeOH) 1m  » Cu(MR) 2 (γ-pic) 2 2b  ≈ Cu(MR) 2 (β-pic) 2 1 , suggesting the significant role of solvent's coordination in enhancing the thermodynamic stability of metal coordination complexes. [ABSTRACT FROM AUTHOR]

A new series of pendant-armed heteroleptic copper(II) phenolate complexes of the type [CuL 1−3 (diimine)] ( 1 – 6 ) have been synthesized by the reaction of pendant-armed ligands 2,2'-(benzoyliminodiethylene)bissalicylidene (H 2 L 1 ), 2,2'-(4-nitrobenzoyliminodiethylene)bissalicylidene (H 2 L 2 ) or 2,2'-(3,5-dinitrobenzoyliminodiethylene)bissalicylidene (H 2 L 3 ) with coligands (diimine; 2,2′-bipyridyl (bpy) or 1,10-phenanthroline (phen)) in the presence of copper(II) chloride, and characterized by spectroscopic techniques. The seven coordinated pentagonal-bipyramidal geometry around the copper(II) center was inferred from the electronic spectra of the complexes. The bond length, bond angle and HOMO-LUMO energy gap calculations were carried out by DFT studies, using Gaussian 03 program. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region ( E pc  = −0.61 to −0.65 V). Experimental and in silico molecular docking studies support groove mode of binding with DNA. Further, the molecular docking studies of complexes with B-DNA indicate the binding of the guanine-cytosine residues in the minor groove of the DNA. Molecular docking studies also revealed the interaction of complexes with protein ERK2 kinase and significant topoisomerase (Topo-I) inhibitory activity. All the complexes display pronounced cleavage activity against supercoiled pBR322 DNA in the presence of H 2 O 2 . In vitro cytotoxicity of the complexes was tested against liver cancer cell line (HepG2) by MTT reduction assay. [ABSTRACT FROM AUTHOR]

Four new metal complexes of a novel Mannich base 5-methyl-2-((4-(pyridin-2-yl)piperazin-1-yl)methyl)phenol (HL) have been prepared. The compounds were characterized by an array of analytical and spectroscopic methods including Nuclear Magnetic Resonance, Infra-red and UV–Visible spectroscopy. Compounds 1–4 behaved as effective catalysts towards the oxidation of 3,5-di- tert -butylcatechol (3,5-DTBC) to its corresponding quinone in the presence of molecular oxygen in DMF solution while compound 4 proved to be the best catalyst with a turnover rate of 17.93 ± 1.10 h −1 as other complexes showed lower rates of oxidation. Also with the exception of dinuclear iron complex ( 4 ); thiocyanate containing Cu(II) complex exhibited lower catecholase activity compared to the Cu(II) complex without it. [ABSTRACT FROM AUTHOR]

Copper complexes of N,N,N′,N ′-tetrakis(pyridyl-2-ylmethyl)-1,2-diaminoethane (L 1 ) and N,N,N′,N′ -tetrakis(pyridyl-2-ylmethyl)-1,3-diaminopropane (L 2 ) prepared were characterized completely by different analytical methods. The X-structure of the complexes shows that Cu(II) presents in trigonal bi-pyramidal (TBP) geometry, consisting with the electronic spectra where two visible bands corresponding to five coordinated structure were observed. Thus TD-DFT was used to analyze the orbital contribution to the electronic transitions for the visible bands. Furthermore, the interaction of cysteine with the complexes was spectrally studied, and the results were explained through DFT analysis, observing that the geometrical parameters and oxidation state of metal ions play a vital role in the binding of cysteine with copper ion. It appears that the TBP structure is being changed into octahedral geometry during the addition of cysteine to the complexes as two bands (from complex) is turned to a broad band in visible region, signifying the occupation of cysteine molecule at sixth position of octahedral geometry. In the molecular orbital analysis, the existence of a strong overlapping of HOMOs (from cysteine) with LUMOs of Cu ion was observed. The total energy of the systems calculated by DFT shows that cysteine binds favorably with copper (I) than that with Cu(II). [ABSTRACT FROM AUTHOR]

A novel O,N,O donor salicylaldehyde–N 4 –phenylsemicarbazone, (H 2 L) has been synthesized and physicochemically characterized. Detailed structural studies of H 2 L using single crystal X–ray diffraction technique reveals the existence of intra and inter molecular hydrogen bonding interactions, which provide extra stability to the molecule. We have successfully synthesized a binuclear copper(II) complex, [Cu 2 (HL) 2 (NO 3 )(H 2 O) 2 ]NO 3 with phenoxy bridging between the two copper centers. The complex was characterized by elemental analysis, magnetic susceptibility and conductivity measurements, FT–IR, UV–Visible, mass and EPR spectral methods. The grown crystals of the copper complex were employed for the single crystal X–ray diffraction studies. The complex possesses geometrically different metal centers, in which the ligand coordinates through ketoamide oxygen, azomethine nitrogen and deprotonated phenoxy oxygen. The extensive intermolecular hydrogen bonding interactions of the coordinated and the lattice nitrate groups interconnect the complex units to form a 2D supramolecular assembly. The ESI mass spectrum substantiates the existence of 1:1 complex. The g values obtained from the EPR spectrum in frozen DMF suggest d x 2 − y 2 ground state for the unpaired electron. [ABSTRACT FROM AUTHOR]

• A novel three-bridged trinuclear [{Co 3 (L) 2 (µ 3 OAc) 2 } 2 ] complex with acetate was constructed. • Fluorescence properties of the ligand and its complexes were studied. • A series of theoretical calculations of the ligand and its complexes were investigated. • The softness of the complexes was proposed and energy gaps were analyzed by DFT calculation. • Quantitative analyses of intermolecular interactions in the crystalline structures were performed by Hirshfeld surfaces analysis. A more flexible 3-methoxysalamo-like ligand H 2 L and its dinuclear Cu(II) complex [Cu 2 (L)(NO 3) 2 ] (1) and novel trinuclear Co(II) complex [{Co 3 (L) 2 (µ 3 OAc) 2 } 2 ]⋅9CH 2 Cl 2 (2) were synthesized. The self-assembly reaction was driven by the unique N , O-donor coordination environments. Single crystal X-ray diffraction analysis showed that two Cu(II) atoms occupy the N 2 O 2 and O 4 cavities of the ligand (L)2− unit in complex 1 , respectively, and two oxygen atoms on the two mono-dentate nitrate groups have also participated in the coordination for the charge balance of complex 1. The stretching of chemical bonds of complex 1 can be perfectly explained by the Jahn-Teller effect. The novel salamo-based Co(II) complex 2 containing µ 3 OAc− coordination mode was discovered for the first time. The trinuclear Co(II) complex embodies the advantage of the salamo-based ligand, which has a good flexible form. The binding ratio of the ligand to the Co(II) center was verified by a UV–Vis titration experiment, which is consistent with the single crystal X-ray diffraction result. The energy gaps between the ligand and complexes 1 and 2 were obtained by DFT calculations, and a new theory-softness was proposed. The degree of softness affected the shapes of the complexes. Hirshfeld analysis, IRI, and electrostatic potential proved the existence of hydrogen bond, π···π, C H···π interactions, and van der Waals force. These weak interaction forces affected the structures of the complexes. Finally, the fluorescence properties of the ligand and its complexes were studied. [ABSTRACT FROM AUTHOR]

• Mixed ligand copper(I) complexes with alkynyl functionalized iminopyridine and substituted ethynylpyridine ligands. • The donor/acceptor moieties induces pronounced red shift in photophysical properties of the complexes. • Quasireversible redox behavior observed for the complexes. • Insertion of ethynylpyridine ligand reduces the HOMO-LUMO energy gap. A series of mixed ligand copper(I) complexes of the formula [Cu(L 1–3)(NC 5 H 4 C CH) (PPh 3)]PF 6 (1a-c), [Cu(L 1–3)(NC 5 H 4 C CC 6 H 4 OCH 3)(PPh 3)]PF 6 (2a-c) and [Cu(L 1–3) (NC 5 H 4 C CC 6 H 4 NO 2)(PPh 3)]PF 6 (3a-c) have been synthesized by the reaction of [Cu(CH 3 CN) 3 (PPh 3)]PF 6 with N-(2-pyridylmethylene)-4-(trimethylsilylethynyl)aniline (L 1), N-(2-pyridylmethylene)-4-(ethynyl)aniline (L 2) and N-(2-pyridylmethylene)-4-(phenylethynyl)aniline (L 3) in presence of NC 5 H 4 C HNC 5 H 4 C CC 6 H 4 OCH 3 and NC 5 H 4 C C C 6 H 4 NO 2. All the complexes have been characterized on the basis of their elemental analyses, IR, 1H NMR, 31P NMR, and TGA-DTA studies. Electrochemical data demonstrate quasireversible redox behavior for all copper(I) complexes. Photophysical properties of all copper(I) complexes indicate that increase in π-conjugation and donor/acceptor substituents on coordinated ligands show a marked effect on the absorption and emission properties of the complexes. DFT computations were performed to gain insight into the effect of the donor/acceptor moiety of coordinated ligands on the HOMO-LUMO gap of the copper(I) complexes. A series of mononuclear copper(I) complexes were synthesized based on alkynyl functionalized iminopyridine and substituted ethynylpyridine ligands. The effect of π-conjugation and donor/acceptor moieties on the ethynylpyridine ligands plays an important role in the photophysical properties of copper(I) complexes. Donor/acceptor effects of conjugated ethynylpyridine ligands on the HOMO-LUMO gap of copper(I) complexes are also investigated by DFT studies. [Display omitted] [ABSTRACT FROM AUTHOR]

• Halo-bridged Cu(II) complexes prepared using pyridine-pyrazole ligands (L1-L3). • Copper(II) complexes exhibited lipophilicity and nature of halogen ligand dependent, selective antimicrobial activity against Gram-positive bacteria. • Dimeric Cu(II) complexes show supramolecular structure facilitated by intermolecular C–H···Cl and C–H···N hydrogen bonding interactions. • Hirshfeld surface analysis further support the intermolecular H-bonding interactions. • Molecular docking studies support the antimicrobial activity of copper complexes. A series of five coordinated, doubly halo bridged Cu(II) complexes [Cu 2 (μ-X) 2 (Ln) 2 × 2 ] (X=Cl and Br; n = 1, 2 and 3), CuL1Cl, CuL1Br, CuL2Cl, CuL2Br, CuL3Cl and CuL3Br (where L1 = 2-((1H-pyrazol-1-yl)methyl)pyridine, L2 = 2-((3-methyl-1H-pyrazol-1-yl)methyl)pyridine, L3 = 2-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine) have been synthesized and structurally characterized using FT-IR and UV–Vis spectroscopy analysis. Moreover, CuL1Cl, CuL1Br and CuL3Cl structures have also been confirmed by single crystal X-ray structural analysis. Copper ion in CuL1Cl, CuL1Br and CuL3Cl displayed distorted squared pyramidal geometry and formed dimers via bridged μ‑chloro/μ‑bromo coordination in the crystal lattice. The intermolecular C–H···Cl hydrogen bonding interaction further connected the dimers of CuL1Cl and CuL3Cl with four neighboring dinuclear complex units. Copper complexes were evaluated for their antimicrobial activity against Gram-negative and Gram-positive bacteria. Interestingly, copper complexes exhibited selective antimicrobial activity against Gram-positive bacteria. Further the increasing ligand lipophilicity showed the increase of antibacterial activity of copper complexes. The lipophilicity of ligands was regulated by number of methyl substituents on the ligands. The chloro bridged copper complexes exhibited relatively higher antibacterial activity compared to the bromo bridged copper complexes. Thus, the present structure-activity of simple copper complexes might provide insight on the structural design of new antimicrobial agents based on coordination complexes. [ABSTRACT FROM AUTHOR]

• The two novel Cu (I) complexes, complex (1) with 2,9-dimethylphenanthroline (dmp) and complex (2) with 1,10-phenanthroline were synthesized by liquid assisted grinding (LAG). • The complex (1) has distorted tetrahedral geometry and complex (2) has distorted square pyramidal geometry. • In complex (2) the intramolecular charge transfer (ICT) is easier due to the small HOMO-LUMO energy gap compared to complex (1). • The Pearson correlation coefficient (r) values are closer to one and the P values are 0.000. • Both the complexes showed higher third order NLO response compared to prototypical urea. The two novel Cu (I) complexes, [Cu(dmp) 2 ]ClO 4 with 2,9-dimethylphenanthroline (dmp) and [Cu(phen) 2 Br] with 1,10-phenanthroline (phen) were synthesized by liquid assisted grinding (LAG) method followed by heating. Complexes were characterized by using SC-XRD, FT-IR and UV-Visible spectroscopic techniques. The complex (1) [Cu(dmp) 2 ]ClO 4 crystallized in the Orthorhombic with the space group P 21 21 21, a = 11.9229 (2) Å, b = 12.4823(3) Å, c = 18.2499(3) Å and Complex (2) [Cu(phen) 2 Br] crystallized in the Monoclinic with the space group C2/c, a = 23.247(5) Å, b = 30.731 (6) Å, c = 7.5317(15) Å and β = 97.677(6)o. The FMOs study based on DFT showed the complex (2) has high value of chemical softness and more easily polarized compare to complex (1). The HOMO-LUMO energy gap in complex (2) is small compared to complex (1) due to which there is easier intramolecular charge transfer (ICT) in complex (2) which support the higher third order NLO (γ) response of the complex (2). The statistical calculations for Pearson correlation coefficient (r) and the P values showed that the selected level of theory is appropriate for the theoretical calculations of the complexes. Theoretical calculation showed that both the complexes have higher third order NLO response compared to prototypical urea. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two novel Cu(І) complexes were synthesized from in situ reduction of Cu(II) to Cu(I). • Both complexes have potential antioxidant capacity and exhibit efficiently self-activated DNA cleavage activity. • The complexes exhibited higher selective cytotoxicity against tumor cells than normal cells. • The complexes could induce cell apoptosis via mitochondrial pathway. • The complexes could obviously inhibit the migration and invasion of the tumor cells. Two new Cu(І) complexes, [Cu 2 (L1) 2 (μ-Br) 2 ] (1) and [Cu 2 (L1) 2 (μ-Cl) 2 ] (2) were synthesized from Cu(II) halogen salts and the reduced Schiff base ligand. Stable Cu(І) complexes were obtained via in situ reduction of Cu(II) to Cu(I) and the C N was oxidize to C = N in the ligand. The structures of two complexes were characterized by X-ray single crystal diffraction analysis as well as IR and UV–Vis spectra. The two complexes have potential antioxidant capacity and exhibit efficiently self-activated DNA cleavage activity and hydroxyl radical ROS cleavage mechanism. MTT was used to assay cytotoxicity of the complexes toward a series of tumor cell and HUVEC cell lines. Both complexes exhibited higher selective cytotoxicity against tumor cells than normal cells, which is significantly superior to the positive control. The complexes could induce cell apoptosis via mitochondrial pathway by increase of ROS levels and decrease of mitochondrial membrane potential (Δψ m). Furthermore, the complexes can obviously inhibit the migration and invasion of the quiz tumor cells, as well as inhibit the angiogenesis of HUVEC cells. Novel Cu(І) complexes were synthesized from in situ reduction of Cu(II) to Cu(I), showing good broad-spectrum anticancer activity and less toxic to normal cells. [Display omitted] [ABSTRACT FROM AUTHOR]

• Synthesis of the new binuclear copper complex of DNBA. • The X-ray molecular and crystal structure. • The Hirshfeld surface analysis shows a hydrophilic nature of the intermolecular interactions. • In silico bioactions of obtained complexes essentially dominate activities of standard drugs. The new binuclear copper complex of 3,5-dinitrobenzoic acid (DNBA) with formula [Cu 2 (DNBA) 4 (H 2 O) 2 ] is synthesized, its X-ray structure has been determined and Hirshfeld surface is calculated. In the complex molecule four ligands are coordinated by bidentate fashion to two copper (II) ions and two water molecules are located in apical positions. The Hirshfeld surface analysis attests that intermolecular interactions are mostly hydrophilic because nearly 80% of contacts are due to ones with the participation of the oxygen atoms. In silico determination of antiviral and antimicrobial activities of the new compound and other before obtained two mixed-ligand complexes demonstrates an enhancement of both types of the biological actions. The maximum improvement of bioactivities takes place in case of mixed-ligand complex with participation of monoethanolamine whereas anti COVID-19 and antimicrobial actions of all metal complexes are more than activities of standard compounds favipiravir and ciprofloxacin. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two novel Cu(II) and Pb(II) metal complexes coupling on 2,4-dihydroxybenzoic acid and 2,2′-bipyridine ligands were synthesized and characterized. • Intermolecular interactions were analyzed by Hirshfeld surfaces and 2D fingerprint plots. • [Cu(C 10 H 8 N 2) 2 (C 7 H 5 O 4)](C 7 H 5 O 4)·3H 2 O changes the decomposition process of RDX from melting decomposition to solid phase decomposition. • The introduction of carbon framework ligand provides a new insight for the design of novel combustion catalysts. To further enhance the catalytic performance of copper/lead 2,4-dihydroxybenzoate salt, two novel ternary complexes, Cu(C 10 H 8 N 2) 2 (C 7 H 5 O 4)·3H 2 O (complex 1) and [Pb(C 10 H 8 N 2)(C 7 H 5 O 4) 2 ]·H 2 O (complex 2) were designed by introducing carbon framework ligand. The molecular structures of complexes 1 and 2 were determined by single crystal X-ray diffraction analysis. Both complex 1 and complex 2 were crystallized in the monoclinic crystal system. The difference is that the central Cu ion in complex 1 is connected to one oxygen atom of the carboxyl group of 2,4-dihydroxybenzoic acid, while the other 2,4-dihydroxybenzoic acid anion only acts as a counterion to balance the charge. But the central Pb ion in complex 2 is connected to four oxygen atoms of the carboxyl groups of two 2,4-dihydroxybenzoic acid and forms a six-coordinated structure. The Hirshfeld surface and associated 2D fingerprint analysis offer valuable insights into the intermolecular interactions within the crystal structure. Importantly, the thermal analysis results show that the thermal decomposition temperature of complex 1 is 204.1 °C, which has better thermal stability than complex 2. Furthermore, complex 1 showed remarkable catalytic activity on RDX compared to complex 2 , and changed the thermal decomposition of RDX from melting decomposition to solid phase decomposition. This study will provide a new insight into development of combustion catalysts. [Display omitted] [ABSTRACT FROM AUTHOR]

• New unsymmetrical complexe structures were confirmed by spectral analyses. • Copper center in CuLT displays an ideal square planar geometry. • Scrutinized compounds are excellent second and third order NLO materials. • High catalytic performances toward cyclohexene epoxidation. • CuLR mimic the functional models of vanadium haloperoxidase enzymes. A series of mononuclear oxovanadium VOLBz, VOLT and copper CuLBz, CuLT complexes containing unsymmetrical tetradentate Schiff base ligands were synthesized and fully characterized by conventional spectroscopic techniques such as FT-IR, UV–vis, 1HNMR and mass spectrometry (MS). Crystal structure data of CuLT, solved by X-ray diffraction, shows a monoclinic system with Cc space group and Z = 4 molecules per unit cell. The central copper ion adopts a nearly ideal square planar coordination geometry. Cyclic voltammetry of oxovanadium and copper complexes revealed quasi reversible redox couples corresponding to VOIV/VOV and CuI/CuII redox processes, respectively. The quantum calculations, performed by DFT and TD-DFT theory at the M062X/6-311**G/SDD level, agree well with the experimental data. The results show that the copper and the oxovanadium compounds have larger static and dynamic hyperpolarizability values than the urea. For instance, the β 0 value of H 2 LT is about 68 times larger than that of the urea. The results predict that the studied compounds have the ability to be excellent second and third-order NLO materials. The prepared complexes catalyzed effectively homogeneous oxidation reaction of cyclohexene in the presence of H 2 O 2 as oxidant. Higher conversion of 98% is attained using CuLBz as catalyst. The bromoperoxidase activity is explored in the oxidative bromination of phenol red as a trap employing the studied complexes which can be considered as potential functional models of bromoperoxidase, CuLBz catalyst exhibits the better catalytic activity, the reaction rate constant k is equal to 2.203×105 (mol L-1)-2s-1. [Display omitted] Oxovanadium and copper complexes are efficient catalysts toward cyclohexene oxidation and phenol red oxidative bromination [ABSTRACT FROM AUTHOR]

• A new azo-azomethine and its metal complexes were prepared and characterized. • The solid state structure of the azo-azomethine ligand was determined by XRD. • Theoretical calculations of possible isomers of the ligand and complexes were studied. • Electrochemical and photoluminescence properties of the compounds were investigated. A new bidentate azo-azomethine ligand 2-{(E)-[(3,4- dimethylphenyl) imino ]methyl}-4-[(E)-(4- ethylphenyl) diazenyl ]phenol (2) and its copper(II) and zinc(II) complexes (3) and (4) were synthesized and characterized by elemental analysis, 1H/13C NMR (for the ligand 2 and its Zn(II) complex) and IR spectral measurements. The structure of the ligand 2 was also determined by single crystal X-ray diffraction. The structure was solved in monoclinic unit cell and P2 1 /n space group with final R value of 0.0586. In the structure of the ligand, the imine (CH N) bond distance is of 1.276(2) Å which confirms the phenol-imine tautmeric form in the crystalline state. In the structure, molecules are stacked by π-π (edge to edge) interactions. The electrochemical and photoluminescence properties of the synthesized azo-azomethine ligand and its metal complexes were investigated. Also, computational studies of related compounds were performed by using M062X/6-31+G level in vacuum. The potential VEGFR2 inhibitory properties of the synthesized ligand and its possible tautomers was investigated by the docking study. As for the ligand structures, azo-imine form is so reactive against the VEGFR2 protein and its docking score and total interaction energy are better than those of other tautomers. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cu benzimidazole complexes 1–6 studied by XANES fingerprinting, EXAFS fitting and XANES simulations. • XANES indicated Cu2+ nature in all complexes with square pyramidal geometry for 1–5. • EXAFS further showed presence of two independent Cu formula units in 1 and 2. • XANES and EXAFS showed that Cu has tetrahedrally distorted square planar structure in 6. • p-DOS and d-DOS were correlated to splitting of white line and intensity of pre-edge peak. X-ray absorption fine structure (XAFS) at the Cu K-edge in copper complexes, viz., [Cu(BzImH) 4 X 2 ], where BzImH= benzimidazole and X= ClO 4 (1), NO 3 (2), ½ SO 4 (3), Br (4), Cl (5) and their 'inner complex' [Cu(BzImH) 2 ] (6) have been investigated using synchrotron radiation. The crystal structures of 4, 5 and 6 are not available. From EXAFS analysis, the structures of 4 and 5 have been estimated to be distorted square pyramidal and that of 6 to be tetrahedrally distorted square planar. Though, the crystal structure of the complexes 1 and 2 have been studied earlier using X-ray crystallography and found to be distorted square pyramidal, these complexes have been included in the study because each of these complexes has two independent formula units having two Cu sites in a molecule. In 2 the axial bond lengths are not similar at Cu1 and Cu2 sites. The electronic nature of Cu metal center in the complexes has been studied using XANES. The XANES spectra have been simulated and p-DOS and d-DOS calculated simultaneously for the Cu center in the complexes. The splitting of Cu K-edge into two edges K 1 and K 2 has been correlated with the p-DOS and the occurrence of pre-edge has been correlated with d-DOS. [Display omitted] [ABSTRACT FROM AUTHOR]

• The modified carbon dots with branched polyethylene imine was prepared. • Some cu compounds immobilized on modified carbon dots. • The prepared heterogeneous catalysts were characterized by means of XRD, FTIR, SEM, TEM and XPS. • The prepared compounds were used as heterogeneous catalysts for homocoupling reactions. • The DFT studies and experimental results are consistent with each other. Carbon dots (CDs) modified with branched polyethylene imine was prepared at 200ºC and designated as BPEI-CDs followed by complexation with CuI, CuBr, CuCl, CuBr 2, CuCl 2 , Cu(bpy) 2 I, Cu(bpy) 2 Cl, Cu(bpy) 2 Cl 2 , Cu(en) 2 I, Cu(en) 2 Cl and Cu(en) 2 Cl 2. After characterization of the prepared heterogeneous compounds by means of XRD, FTIR, SEM, TEM and XPS, they were tested as catalysts for the oxidative homo-coupling of phenylacetylene, 4‑ tert -butylphenylacetylene, 1-ethynyl-4-flourobenzene and 1- pent‑1-yn-3ol. It was found that Cu (I) I and Cu (I) bipyridene show conversion yields of 67–100% with excellent selectivities (95–100). The catalysts were also recovered and used for four runs without significant decrease in catalytic activities. Based on the density functional theory (DFT) studies on activity of substrates, 1-ethynyl-4-flourobenzene was found to show the most activity, consistent with those reported in experimental results. [Display omitted] [ABSTRACT FROM AUTHOR]

The N, N ′-dicyclohexylurea-capped benzo-12-crown-4 (compound 1 ) has been synthesized. The coordination behaviour of this compound ( 1 ) has been studied by crystallizing it with KI ( 2 ) and Cu(ClO 4 ) 2 ( 3 ) salts. The crystallographic studies were performed with all three compounds. The presence of metal ions significantly affects the crystal packing of the compound 1 . The crystal lattice of compound 1 was stabilized by C H⋯π and C O⋯H N hydrogen bonding. The presence of KI in compound 2 results in a dimer structure in which iodide anion behaves as a bridging ligand. The K + forms a perching structure with the crown ring. In the compound 3, Cu 2+ ion and ligand molecule ( 1 ) crystallized independently. They were connected through hydrogen bonding. Interestingly, Cu 2+ adopts two different geometries with the coordination number 5 and 6. The centre Cu 2+ (Cu1) adopted an octahedral geometry whereas the terminal Cu 2+ (Cu2) acquired square pyramidal geometry. The coordination sphere of Cu 2+ contains ClO 4 − anion and water molecules. Cu 2+ ion forms a chain structure through ClO 4 − anion and water molecules involve in hydrogen bonding with the ligand molecule. [ABSTRACT FROM AUTHOR]

Two copper (II) complexes of ligands H 2 L 1 and H 2 L 2 have been prepared and investigated. The ligands were prepared by the individually addition of picolinic acid hydrazide and 2-(2-aminothiazol-4-yl) acetohydrazide into benzoyl isothiocyanate. The results of analytical and spectroscopic equipments revealed that H 2 L 1 act as monobasic bidentate with square planner environment. While H 2 L 2 behaves as monobasic tetradentate with Oh geometry. The geometries of ligands and their complexes being carefully studied using Jaguar 9.1 program based on the density functional theory (DFT) to predict properties of materials performed by the hybrid density functional method B3LYP. Additionally, thermal degradation data were evaluated to determine the kinetic and thermodynamic parameters by different methods. Moreover, the anti-oxidant (using DPPH and SOD methods), and anti-bacterial activities of the compounds have been studied. Furthermore, the docking study of ligands and their complexes were applied against gram-positive S. Aureus , negative E. Coli bacterial and C. Albicans fungal strains by Schrödinger suite program using XP glide protocol. [ABSTRACT FROM AUTHOR]

Present study describes the synthesis and single crystal X-ray structures of two metal complexes of benzimidazole derivative (PBI), viz. the Cu(II) complex, [Cu(PBI) 2 (NCS)]ClO 4 (1) and a Co(II) complex, [Co(PBI) 2 (NCS) 1.75 Cl 0.25 ] (2). The Cu(II) complex (1) shows catecholase like activity having K cat = 1.84 × 10 4 h −1 . Moreover, interactions of the complexes with hydrogen peroxide have been investigated using fluorescence spectroscopy. The interaction constant of 1 and 2 for H 2 O 2 are 6.67 × 10 2 M −1 and 1.049 × 10 3 M −1 while their detection limits for H 2 O 2 are 3.37 × 10 −7 M and 2.46 × 10 −7 M respectively. [ABSTRACT FROM AUTHOR]

In this work, we present the synthesis of the unsymmetrical β-diketone 1-(2-thienyl)-3-(4-fluorophenyl)-propane-1,3-dione ( HL) and its corresponding Co(II), Ni(II) and Cu(II) bis (β-diketonato) complexes 1 – 3 , respectively. The four new compounds were isolated in good yields (65–70%), and characterized by mass spectrometry, elemental analysis, FT-IR and UV–Vis spectroscopy and, in the case of HL, by 1 H, 13 C and 19 F NMR spectroscopy. In addition, the molecular identities and the geometries of the β-diketone HL and complex 3 were confirmed by X-ray diffraction analysis. The dicarbonyl derivative HL does exist as the diketo tautomeric form in DMSO solution and as its keto-enol tautomer in the solid-state with the OH group adjacent to the 4-fluorophenyl unit. The keto-enol isomer was computed to be more stable by 8.2 kcal/mol in free energy at room temperature. In 3 , the Cu(II) center adopts a perfect square-planar geometry. Two reduction processes were observed in the cyclovoltammogram of 3 at −1.30 and −1.80 V vs. Fc/Fc + , with copper deposit on the surface of the electrode. DFT and TD-DFT calculations on HL and complex 3 allow rationalizing their stability, bonding and properties. [ABSTRACT FROM AUTHOR]

First series transition metals are used abundantly by nature to perform catalytic transformations of several substrates. Furthermore, the cooperative activity of two proximal metal ions is common and represents a highly efficient catalytic system in living organisms. In this work three dinuclear μ-phenolate bridged metal complexes were prepared with copper(II) and zinc(II), resulting in a ZnZn, CuCu and CuZn with the ligand 2-ethylaminodimethylamino phenol (saldman) as model compounds of superoxide dismutase (CuCu and CuZn) and metallo-β-lactamases (ZnZn). Metals are coordinated in a μ-phenolate bridged symmetric system. Cu(II) presents a more distorted structure, while zinc is very symmetric. For this reason, [CuCu(saldman)] shows higher water solubility and also higher lability of the bridge. The antioxidant and hydrolytic beta-lactamase-like activity of the complexes were evaluated. The lability of the bridge seems to be important for the antioxidant activity and is suggested to because of [CuCu(saldman)] presents a lower antioxidant capacity than [CuZn(saldman)], which showed to present a more stable bridge in solution. The hydrolytic activity of the bimetallic complexes was assayed using nitrocefin as substrate and showed [ZnZn(saldman)] as a better catalyst than the Cu(II) analog. The series demonstrates the importance of the nature of the metal center for the biological function and how the reactivity of the model complex can be modulated by coordination chemistry. [ABSTRACT FROM AUTHOR]

Two new Ni(II) and Cu(II) complexes of a tetradentate Schiff base ligand ( 1 and 2 , respectively), derived from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with 2-hydroxy-6-methoxy benzaldehyde, were synthesized and characterized by IR, UV–Vis, 1 H NMR spectroscopy, and X-Ray crystallography. The central metal ions in both complexes are coordinated via the N 2 O 2 coordination sphere of the ligand with square-planar geometry. DFT results revealed that the M N and M O interactions (M = Ni, Cu) are weaker than the typical covalent single bond indicating that ionic and electrostatic interactions are dominated in M N and M O bonds. Hirshfeld surface (HS) analyses of the studied structures 1 and 2 have been performed. The study using 3D HSs and 2D fingerprint plots (FPs) highlighted the dominant contacts H⋯H, C⋯H/H⋯C and O⋯H/H⋯O in both structures, and H⋯Cl in 2 . The molecular assemblies held by C⋯O/O⋯C (in 1 ) and C⋯C (in 1 and 2 ) type dipole–dipole interactions are also found in the crystal packing contributing towards stability. The significant contributions arising from the mentioned interactions in crystal packing are also revealed from the Hirshfeld surface FPs showing a major contribution to total HS area for the H⋯H contacts for both structures. [ABSTRACT FROM AUTHOR]

A novel organic-inorganic hybrid sample [C 6 H 10 (NH 3 ) 2 ]Cu 2 Cl 8 has been prepared under mild hydrothermal conditions and characterized by single crystal X-ray diffraction, Hirshfeld surface analysis, FT-IR,NMR and UV–Vis spectroscopies, differential scanning calorimetric and dielectric measurement. It is crystallized in the monoclinic system with P 2 1 / c space group. The cohesion and stabilization of the structure are provided by the hydrogen bond interactions, (N H⋯Cl and C H⋯Cl), between [C 6 H 10 (NH 3 ) 2 ] 2+ cation and [Cu 2 Cl 8 ] 2- anion. The Hirschfeld surface analysis has been performed to explore the behavior of these weak interactions. The presence of different functional groups and the nature of their vibrations were identified by FT-IR and Solid state NMR. The thermal study revealed that this compound undergoes two structural phase transitions around 353 and 376 K. Electrical measurements of our compounds have been investigated using complex impedance spectroscopy (CIS) in the frequency and temperature range 331–399 K and 200 Hz–5 MHz, respectively. The AC conductivity is explained using the correlated barrier hopping model (CBH) conduction mechanism. The nature of DC conductivity variation suggests Arrhenius type of electrical conductivity. A relationship between crystal structure and ionic conductivity was established and discussed. Finally, the real and imaginary parts of the permittivity constant are analyzed with the Cole–Cole formalism and the optical spectra indicate that the compound has a direct band gap (3.14 eV) due to direct transition. The wide band gap is due to low defect concentration in the grown crystal, which is more useful for the laser/optical applications. [ABSTRACT FROM AUTHOR]