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A new doubly carboxylato-bridged Co(II) dinuclear complex, [Co(bdtbpza)(NCS)]2 (1), was obtained in a satisfactory yield by employing a 'scorpionate'-type precursor, bdtbpza {bis-(3,5-di-tert-butylpyrazol-1-yl)acetate}, and was then structurally characterized. Single-crystal X-ray diffraction analysis revealed that, in 1, each Co(II) is penta-coordinated, leading to a distorted trigonal–bipyramidal geometry within the coordination environment of N3O2. Weak antiferromagnetic coupling within the Co(II) ions in 1 was found based on the isotropic spin Hamiltonian H = −J(S1·S2) for the Si = 3/2 system. For evaluating the spin density distribution and the mechanism for the magnetic exchange coupling, DFT analysis was performed, with the calculated result agreeing the experimental magnetic data. A study into electrochemical H2 evolution, involving cyclic voltammetry (CV), controlled potential electrolysis (CPE), and gas chromatographic (GC) analyses of the graphite electrode modified with the cobalt complex in a neutral aqueous solution revealed the high catalytic activity of the complex with a low overpotential toward H2O reduction. The faradaic efficiency of the catalyst was found to be 83.7% and the di-cobalt catalyst-modified electrode displayed quite an interesting H2-evolution activity compared with that of bare electrodes. These results are encouraging for the future potential application of 1 in water splitting. [ABSTRACT FROM AUTHOR]

With the increase in demand of electronic devices in the modern civilization, research in material science is being projected to grow in faster rate. In this facet, coordination polymer (CP) based electronic device is one of the promising candidates to the material researchers. Herein, two new Zn(II) and Cd(II) based one‐dimensional (1D) CPs, denoted as [Zn(4‐avp)2(5‐nip)] ⋅ (solvent)x (1) and [Cd(4‐avp)(5‐nip)(CH3OH)] (2) have been synthesized using relatively less explored highly conjugated polycyclic aromatic hydrocarbon (PAH) based monodentate ligand, 4‐[2‐(9‐anthryl)vinyl]pyridine (4‐avp) and bidentate linker 5‐nitroisophthalic acid (H25‐nip). In this instance, the CP 1 creates 1D chain polymer, while CP 2 is made up with 1D ladder polymer. It is interesting to note that both the CPs exhibit semiconducting nature and generate metal‐semiconductor (MS) junction Schottky barrier diodes (SBDs). However, Cd‐based CP 2 shows higher charge transport as compared to Zn‐CP 1, which could be due to stronger π⋅⋅⋅π contacts as well as larger size of Cd metal in CP 2. The experimental results are well corroborated with theoretical density of states (DOS) calculations. [ABSTRACT FROM AUTHOR]

Three new PbII complexes [Pb(LI)(SCN)]n, {[Pb(LII)](SCN)}n and {[Pb(HLIII)(SCN)](SCN)}n (HLI = N′-phenyl(pyridin-2-yl)methylene-N-phenylthiosemicarbazide, HLII = N′-amino(pyrazin-2-yl)methylenethiosemicarbazide, HLIII = N′-amino(pyridin-2-yl)methylenethiosemicarbazide) have been synthesized and characterized by spectroscopic techniques and single crystal X-ray diffraction. In all complexes, the corresponding organic ligand behaves as a tridentate N,N′,S-chelating species. A 1D supramolecular polymeric aggregation in complex [Pb(LI)(SCN)]n is dictated by the Pb⋯NCS and Pb⋯S＝C tetrel bonds formed between the [Pb(LI)(SCN)] species. 1D cationic coordination polymers ([Pb(LII)])nn+ in the structure of complex {[Pb(LII)](SCN)}n are linked into a 2D supramolecular polymeric layer through the Pb⋯NCS tetrel bonds and Pb⋯π(NCS) interactions formed with the nitrogen atom and the conjugated system of the free SCN− anions, respectively. The cationic species [Pb(HLIII)(SCN)]+ in the structure of complex {[Pb(HLIII)(SCN)](SCN)}n produce a 1D supramolecular polymer due to the Pb⋯SCN and Pb⋯S＝C tetrel bonds, further stabilized by the Pb⋯π(NCS) interactions formed with the conjugated system of the coordinated NCS− anion. The latter anions also link these 1D chains through the Pb⋯SCN tetrel bonds, yielding 1D supramolecular polymeric ribbons. The energetic relevance of the Pb⋯S and Pb⋯N tetrel bonds has been studied by DFT calculations. The tetrel bonds have been characterized using QTAIM and NCIplot analysis and rationalized using molecular electrostatic potential surface calculations. [ABSTRACT FROM AUTHOR]

Zn(II) coordination polymers are being increasingly studied for their stability and properties. Similarly, there is a growing interest in imidazo[1,5-a]pyridine derivatives, which show great potential in luminescence and pharmaceutical applications. In this work, we successfully synthesized and crystallized three new coordination polymers, using Zn(II) as the metallic node, dicarboxylic acids of different length and nature as linkers, and a linear ditopic imidazo[1,5-a]pyridine derivative, to explore the role of this molecule as a propagator of the dimensionality of the structure or as an ancillary ligand. Our work demonstrates the structural capability of imidazo[1,5-a]pyridines in an unexplored domain for this family of ligands. Notably, we observed a pronounced ability of this heterocyclic scaffold to establish π···π interactions in the solid state. The supramolecular π-stacked assemblies were theoretically analyzed using DFT calculations based on model structures. [ABSTRACT FROM AUTHOR]

Two Na(I) coordination polymers, namely, {Na(BA)2(μ-H2O)2}n{adp}n (1) and {[Na2(μ-BA)(μ-fum)(μ-H2O)4](BA)}n (2) (where, BA = boric acid, adp = adipic acid, fum = fumarate),were prepared and characterized using elemental analysis, TGA, FT-IR, and single-crystal X-ray diffraction techniques. Various unconventional supramolecular interactions, i.e., CH∙∙∙HC and parallel CO∙∙∙CO interactions, stabilize the layered assembly of compound 1. Interesting dual enclathration of BA molecules within the supramolecular host cavities formed by O-H∙∙∙O and C-H∙∙∙C interactions stabilizes the crystal structure of compound 2. The H-bonding interactions in 1 and 2 were further studied theoretically using the quantum theory of atoms in molecules (QTAIM) and the noncovalent interaction plot (NCI Plot) computational tools. The energy of the H-bonds was estimated using the potential energy density at the bond critical points. Theoretical calculations confirmed the presence of O-H∙∙∙O H-bonding interactions in both compounds, forming structure-guiding R 2 2 (8) synthons relevant for the stability of the compounds. [ABSTRACT FROM AUTHOR]

Two multi-component coordination compounds of Mn(II), viz. [Mn(H2O)6](2-Mepy)2(4-NO2bz)2·2H2O (1) and [Mn(H2O)6][Mn(2,3-PDCH)3]2 (2) (where, 2-Mepy = 2-methylpyridine, 4-NO2bz = 4-nitrobenzoate, 2,3-PDC = 2,3-pyridinedicarboxylate), have been synthesized and characterized using elemental, spectroscopic (FT-IR and electronic), TGA and single-crystal X-ray diffraction analyses. Complex 1 is a co-crystal hydrate of Mn(II) involving uncoordinated 2-Mepy, 4-NO2bz and water molecules; while compound 2 is a multi-component molecular complex salt of Mn(II) comprising cationic [Mn(H2O)6]2+ and anionic [Mn(2,3-PDCH)3]−complex moieties. The uncoordinated 2-Mepy and 4-NO2bz moieties of 1 are involved in lone-pair (l.p)-π and C–H⋯π interactions which stabilize the layered assembly of the compound. The crystal structure of compound 2 has been previously reported. However, we have explored the unusual enclathration of complex cationic moieties within the supramolecular host cavities formed by the molecular assembly of complex anionic moieties. The supramolecular assemblies obtained in the crystal structure have been further studied theoretically using DFT calculations, quantum theory of atoms-in-molecules (QTAIM) and non-covalent interaction plot (NCI plot) computational tools. Theoretical studies reveal that the combination of π-staking interactions (l.p-π, π-π and C–H···π) have more structure-guiding roles compared to the H-bonds. The large binding energy of π-stacking interactions in 2 is due to the antiparallel orientation of aromatic rings and their coordination to the metal centers, thereby increasing the contribution of the dipole–dipole interactions. [ABSTRACT FROM AUTHOR]

Optically-active luminescent materials based on lanthanoid ions attract significant attention due to their unique spectroscopic properties and the possibility of application as chemical sensors. Five isostructural lanthanoid metal organic frameworks, namely {[Pr(3,4-PDA)(Glu)0.5(H2O)2]CH3CN}(1) and [Ln(3,4-PDA)(Glu)0.5(H2O)2]: Ln = Nd (2), Sm (3), Eu (4), and Tb (5) (where 3,4-PDA = pyridine-3,4-dicarboxylic acid, Glu = glutaric acid), synthesized via the solvothermal method are reported. These lanthanoid metal–organic frameworks were characterized by FTIR, single-crystal X-ray diffraction, powder X-ray diffraction, BET, Hirshfeld surface analysis, DFT calculations, electronic spectroscopy, and photoluminescence techniques. MOFs 1–5 show porous two-dimensional (2D) structures. The luminescence properties of MOFs 4 and 5 demonstrated the range of sensing capabilities for some toxic heavy metals. However, MOFs 4 and 5 are highly sensitive for the detection of Pb2+, exhibiting the most effective luminescence quenching with the lowest detectable change in the signal occurring at ∼0.014 and ∼0.013 ppm of Pb2+ with MOFs 4 and 5, respectively, at room temperature in minutes. The MOF-based luminescence sensors designed in this paper demonstrate a successful and feasible strategy to use pyridine-3,4-dicarboxylic acid-based ligand as an antenna, which can efficiently sensitize Eu3+ and Tb3+ emission. MOFs 4 and 5 show great potential in the application of environmental detection of Pb2+ in water. [ABSTRACT FROM AUTHOR]

A nickel(II)–zinc(II) complex, [(NiL)Zn(μ1,3-NCS)2]n (1), and a nickel(II)–mercury(II) complex, [{(NiL)Hg(μ1,3-SCN)(SCN)}2] (2), (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine) were synthesized via a metalloligand approach, in which the former is a 2D coordination polymer and the latter is a discrete tetramer. Single-crystal X-ray crystallography revealed that Zn(II) in 1 and Hg(II) in 2 are in a four-coordinated distorted tetrahedral environment whereas the geometry of the Ni(II) centre is distorted octahedral for complex 1 but distorted square planar for complex 2. DFT calculations were used to analyze an intramolecular weak interaction between the square planar Ni(II) ion and the N-end of thiocyanate ions, which can be defined as a π-hole interaction. Moreover, we analyzed the tetranuclear structure of 2 in terms of a self-assembled dimer via the formation of two strong spodium bonds instead of Hg–N coordination bonds, as evidenced by the QTAIM and NCI plot analysis and the magnitude of the dimerization energy. [ABSTRACT FROM AUTHOR]

Two Zn(II) coordination polymers, viz., [Zn2Cl2(H2O)2(µ-4-AmBz)2]n (1) and [ZnCl2(µ-3-AmPy)2]n (2) (4-AmBz = 4-aminobenzoate, 3-AmPy = 3-aminopyridine) have been prepared at room temperature and characterized using elemental analysis, FT-IR, electronic spectroscopy, TGA (thermogravimetric analysis) and single crystal XRD. Crystal structure analyses of the polymers unfold the presence of non-covalent anion–π, π-stacking and unusual NH2(amino)⋯π interactions which provide rigidity to the crystal structures. Unconventional Type I Cl⋯Cl interactions also play a pivotal role in the stability of compound 1. Molecular electrostatic potential (MEP) surface analysis reveals that the MEP values over the center of the aromatic rings of coordinated 4-AmBz and 3-AmPy moieties are positive on one side and negative on the other side which confirms the dual non-covalent donor-acceptor topologies of the aromatic rings and explains the concurrent formation of unusual non-covalent NH2···π and anion–π interactions. DFT (density functional theory) calculations, QTAIM (quantum theory of atoms in molecules) and NCI plot (non-covalent index) index analyses reveal that among various non-covalent contacts involved in the crystal packing of the compounds, H-bonds in compound 1 and π-interactions (NH2···π, π-π, anion–π) in compound 2 are energetically significant. We have explored in vitro cytotoxic potential of the compounds in Dalton's lymphoma (DL) cancer cells using trypan blue and apoptosis assays. The studies show that compounds 1 and 2 can significantly exhibit cytotoxicity in DL cells with minimum cytotoxicity in healthy PBMC cells. Molecular docking studies reveal that the compounds effectively bind with the antiapoptotic target proteins; thereby establishing a structure activity relationship of the compounds. [ABSTRACT FROM AUTHOR]

A Cu(II)-based metal–organic framework (MOF) [Cu(muco)(3,5-DCP)]n (1) has been synthesized by using linear rigid aliphatic dicarboxylic acid, trans,trans-muconic acid (H2muco) and 3,5-dichloropyridine (3,5-DCP) as an auxiliary ligand. The MOF adopts a square-grid two-dimensional (2D) structure with paddle-wheel [Cu2(OOC)4] robust secondary building units (SBUs). The 3,5-DCP ligands are perpendicularly projected from the SBUs at both sides and undergo interdigitation via antiparallel π⋯π stacking interactions among 3,5-DCP ligands to fabricate three-dimensional (3D) supramolecular architecture. The π⋯π interactions favour the formation of Cl⋯Cl stacking contacts. These non-covalent interactions are further validated by density functional theory (DFT) calculation. In addition, the synthesized MOF is tested for conductivity measurements via current density–voltage characteristics, as well as impedance spectroscopy, which reveal that the MOF is semiconducting in nature and can be used as a Schottky diode. [ABSTRACT FROM AUTHOR]

Thiophenyl-isonicotinohydrazide, a multidentate Schiff base, acts as a tridentate N,O,N donor out of which N,O-chelates to one Zn(II) and pyridyl-N links to the adjacent Zn(II) to constitute a 2D coordination polymer, {[Zn(SIZ)2]·DMF}n (CP1) (HSIZ = (E)-N′-(thiophen-2-ylmethylene)isonicotinohydrazide, DMF = N,N-dimethylformamide). CP1 has been characterized by different physicochemical data and confirmed by single crystal X-ray crystallographic measurement. The H-bonding, C–H⋯π and π⋯π interactions in the 2D geometry of the coordination polymer creates a 3D architecture. The Tauc plot for CP1 indicates an optical band gap of 2.91 eV (calc., 2.48 eV) (direct)/2.80 eV (calc., 2.50 eV) (indirect) and CP1 is non-conducting (2.53 × 10−9 Sm−1) in the dark while it is enhanced by ∼23 000 times (5.97 × 10−5 Sm−1) upon light irradiation (1000 Wm−2). Considering the biological importance of isoniazid and Zn(II) the antimicrobial activities of CP1 is measured against Staphylococcus aureus and Escherichia coli (MIC, 20 μg mL−1). The cytotoxic potency of CP1 is examined on thirty different cancer cell lines which has been found active against four cancer cell lines, HCT-116 (colon cancer), HeLa (cervical cancer), MDA-MB-231 (human breast cancer cell), and HepG2 (hepatocellular carcinoma) and the results are compared with the human normal kidney epithelial cell line, NKE. However, CP1 shows the highest anticancer efficiency against HeLa (IC50: 9.13 ± 2.32 μg mL−1) cells. The mechanism of cell killing activity may presumably be the generation of intracellular reactive oxygen species as suggested by the caspase 3/7 activation assay. [ABSTRACT FROM AUTHOR]

Three coordination complexes {[Cu(pydco)(pz)0.5(H2O)]·H2O}n (1), [Cu(pydco)(phen)(H2O)]·2H2O (2), and [Zn2(pydco)(phen)2Cl2]·2H2O (3) have been synthesized at room temperature using a mixed-ligand system including pyridine-2,6-dicarboxylic acid N-oxide (H2pydco) as O-donor as well as pyrazine (pz) and 1,10-phenanthroline (phen) as N,N′-bidentate donors. Single-crystal X-ray diffraction (XRD) revealed that 1 forms a 1D-coordination polymer through bridging pz units while 2 and 3 form discrete complexes in which endo-bidentate phen can only connect with one metal centre via a five-membered chelate ring. Also, pydco2− can form a six-membered chelate ring around the metal ion via the N-oxide oxygen and one carboxylate oxygen. However, another carboxylate group of this ligand can also participate in the coordination and create unique structures in 1 and 3. Subsequently, 1–3 can expand their structures into 2D-supramolecular networks through π⋯π stacking or H-bonding interactions. Recurrent π⋯π stacking motifs in all compounds have been further analyzed energetically using DFT calculations and characterized using the quantum theory of "atoms-in-molecules" (QTAIM) and noncovalent interaction plot (NCIPlot) index computational tools. In compound 3, cooperativity effects in π⋯π/π⋯π/π⋯π assemblies have been also analyzed. [ABSTRACT FROM AUTHOR]

A new PbII coordination complex [PbL(OAc)], which was readily synthesized from a mixture of Pb(OAc)2·3H2O and 1‐(pyridin‐2‐yl)benzylidene‐4‐phenylthiosemicarbazide (HL) is reported. The crystal structure analysis of [PbL(OAc)] showed that the PbII cation is N,N′,S‐chelated by the tridentate pincer‐type ligand L and by the oxygen atoms of the acetate anion. In addition, the metal centre forms Pb...O and Pb...S tetrel bonds with an adjacent complex molecule, yielding a 1D zigzag polymeric chain, which is reinforced by N—H...O hydrogen bonds and π...π interactions. These chains are interlinked by C—H...py non‐covalent interactions, realized between one of the acetate hydrogen atoms and the pyridine rings. According to the Hirshfeld surface analysis, the crystal packing is mainly characterized by intermolecular H...H, H...C and H...O contacts, followed by H...N, H...S, C...C, C...N, Pb...H, Pb...O and Pb...S contacts. The FTIR and 1H NMR spectra of [PbL(OAc)] testify to the deprotonation of the parent ligand HL, while the acetate ligand exhibits an anisobidentate coordination mode as established by means of single‐crystal X‐ray diffraction and FTIR spectroscopy. Lastly, theoretical calculations at the PBE0‐D3/def2‐TZVP level of theory have been used to analyze and characterize the Pb...O and Pb...S tetrel bonds observed in the crystal of [PbL(OAc)], using a combination of QTAIM (Quantum Theory of Atoms in Molecules) and NCIPlot (Non‐Covalent Interaction Plot) computational tools. [ABSTRACT FROM AUTHOR]

In this study the ability of metal coordinated Chalcogen (Ch) atoms to undergo Chalcogen bonding (ChB) interactions has been evaluated at the PBE0-D3/def2-TZVP level of theory. An initial CSD (Cambridge Structural Database) inspection revealed the presence of square planar Pd/Pt coordination complexes where divalent Ch atoms (Se/Te) were used as ligands. Interestingly, the coordination to the metal center enhanced the σ-hole donor ability of the Ch atom, which participates in ChBs with neighboring units present in the X-ray crystal structure, therefore dictating the solid state architecture. The X-ray analyses were complemented with a computational study (PBE0-D3/def2-TZVP level of theory), which shed light into the strength and directionality of the ChBs studied herein. Owing to the new possibilities that metal coordination offers to enhance or modulate the σ-hole donor ability of Chs, we believe that the findings presented herein are of remarkable importance for supramolecular chemists as well as for those scientists working in the field of solid state chemistry. [ABSTRACT FROM AUTHOR]

A coordination polymer (1) and a trinuclear complex (2) have been synthesized using a compartmental N2O2O2′ donor Schiff base ligand. Both complexes are characterized using different spectroscopic techniques and their structures are determined using single crystal X-ray diffraction analyses. Energies associated with different non-covalent (S⋯O chalcogen bonds, C–H⋯H–C, C–H⋯I and C–H⋯π) interactions in the solid state of both complexes have been calculated using the Turbomole program. Investigations of electrical conductivity and photosensitivity of both complexes reveal that suitable Schottky diode devices could be fabricated from both complexes. The current vs. voltage plots of the complex based devices have been used to calculate the conductivity under dark and irradiation conditions. In both complexes the charge transportation mainly occurs through space which involves the hopping process. Standard band theory has been used to compare the experimental and theoretical results of optoelectronic measurements. The calculations confirm that both are direct band gap (2.78 and 3.30 eV) semiconductors and that complex 1 exhibits a lower band gap, in line with the experimental results (3.21 and 3.43 eV in 1 and 2, respectively). [ABSTRACT FROM AUTHOR]

Two new poly-nuclear coordination compounds of Zn(II) and Mn(II) viz. [Zn2(male)2(3-AMpy)4]·3H2O (1) and [Mn(H2O)2(μ-fum)(3-CNpy)2]n (2) (male = maleate, fum = fumarate, 3-AMpy = 3-aminopyridine, 3-CNpy = 3-cyanopyridine) have been synthesized and characterized using single crystal X-ray analysis, elemental analysis, FT-IR spectroscopy, electronic spectroscopy and TGA. Compound 1 crystallizes as a maleato bridged Zn(II) di-nuclear complex, whereas compound 2 is a fumarato bridged coordination polymer of Mn(II). The lattice water molecules of compound 1 are aggregated via O–H⋯O hydrogen bonding interactions to form V-shaped (H2O)3 clusters which are enclathrated within the supramolecular layered assembly of the crystal structure. Unconventional N(nitrile)⋯π(fum) and antiparallel nitrile⋯nitrile contacts are involved in the stabilization of the 2D assembly of compound 2. The existence of such N(nitrile)⋯π(fum) interactions has been scarcely reported in the literature. Aromatic π-stacking combined with strong N–H⋯O H-bonding assemblies in 1 and unconventional N(nitrile)⋯π(fum) interactions in 2 have been further studied using DFT calculations and NCI plot computational tools. The energetic analysis of 2 indicates that the unconventional N(nitrile)⋯π(fum) interaction is energetically significant and a dominant force for the supramolecular assembly. Antiproliferative evaluation of the compounds reveals that the compounds induced significant cytotoxicity in Dalton's lymphoma (DL) cancer cell lines with nominal effects in normal healthy PBMC cells. The molecular docking study corroborates the results obtained in the apoptosis assays and established structure–activity relationships. [ABSTRACT FROM AUTHOR]

A new heterocyclic ligand, N3L [4-(1-methylimidazole)-2,6-di(pyrazinyl)pyridine] has been synthesized and characterized by several spectroscopic methods. The ligand (N3L) was then used for the preparation of two complexes, namely, [Cu(N3L)Cl2] (complex 1) and [Cu(N3L)(Cl)(μ-ONO2)]n (complex 2). The crystal structures of these complexes have been established by single-crystal X-ray diffraction analysis. Complex 1 is a mononuclear one whereas complex 2 is a 1D coordination polymer. The structural insights reveal that non-classical hydrogen bonding (C–H⋯Cl, C–H⋯O, C–H⋯N) and π⋯π stacking interactions play a crucial role in stabilizing various supramolecular architectures of the title complexes in the solid state. All the non-classical hydrogen bonding interactions are quantified through the infographic 2D fingerprint plots. Additionally, theoretical calculations (density functional theory) were carried out for both complexes to analyze these non-covalent interactions in the solid state including their characterization using Bader's theory of atoms in molecules and the noncovalent interaction (NCI) plot index. [ABSTRACT FROM AUTHOR]

The important role of spodium bonding (SpB) in Zn(II) and Cd(II) complexes is highlighted in this feature article. SpB has been recommended to distinguish coordination bonds (high covalent character) from non-covalent contacts. Here, two new d10-metal dithiophosphate complexes, [M(L)2]2 {where M = Zn (1) and Cd (2); L = O,O′-bis(4-tert-butylphenyl) phosphorodithioate} have been synthesized in purely aqueous media and characterized by elemental and spectral analyses. The X-ray crystallography analyses indicate that both complexes are dinuclear, in which each metal atom is coordinated with four sulfur atoms in a distorted tetrahedral environment containing two four-membered chelate rings joined to a central eight-membered ring through metal (Zn/Cd) atoms. In complex 1 the eight-membered ring possesses a "saddle" conformation located on a two-fold axis of symmetry, C2, while in complex 2 it possesses a centrosymmetric "twisted chair" conformation, Ci. In addition, the oxygen and sulfur atoms belonging to the bridging ligands form intramolecular SpBs with Zn(II) in 1 and Cd(II) in 2. The existence of intramolecular SpBs in both complexes is evidenced by DFT calculations by using the Bader's Quantum Theory of Atoms-in-Molecules (QTAIM) combined with the non-covalent interaction plot (NCI plot) index that is based on the reduced density gradient (NCI-RDG) method. A Hirshfeld surface study has been carried out to understand the intermolecular contacts in the crystal lattice. [ABSTRACT FROM AUTHOR]

Two new coordination polymers of Zn(II), viz. {[Zn(Hdmpz)2(μ-male)]·(MeOH)(H2O)}n (1) and [Zn(3-AMpy)2(μ-fum)(H2O)2]n (2) (where Hdmpz = 3,5-dimethylpyrazole, male = maleate, fum = fumarate, and 3-AMpy = 3-aminopyridine), have been synthesized and characterized using elemental analysis, TGA, spectroscopic and single crystal X-ray diffraction techniques. The 1D polymeric chains of the polymers self-assemble into 2D supramolecular architectures via several non-covalent interactions. Differences in the structural topologies have been observed with the change of solvent from the methanol–water mixture in compound 1 to de-ionized water in compound 2. Unconventional enclathration of the solvent molecules, viz. MeOH, and the water in the crystal structure of 1 results in an interesting layered assembly. The influences of the metal coordination on the strength of the π-stacking interactions have been explored theoretically for compound 2, which confirms that the coordination of 3-AMpy to the Zn(II) centre strongly polarizes the π-cloud and increases the local dipole of 3-AMpy, thereby enhancing the strength of π-stacking interactions. The in vitro anticancer activities of the compounds have been explored in Dalton's lymphoma cancer cell lines considering cell cytotoxicity and apoptosis, and the results were compared with those observed for cisplatin (reference drug) under the same experimental conditions. The in silico molecular docking studies and the pharmacophore features further corroborate the cytotoxicity and apoptosis inducing ability of the compounds. [ABSTRACT FROM AUTHOR]

Two coordination complexes [Ni(Hpydco)2(bpy)] (1) and [Ni(pydco)(phen)(H2O)2]·4.5H2O 0.5CH3OH (2) have been synthesized using a mixed-ligand system including pyridine-2,5-dicarboxylic acid N-oxide (H2pydco) as an O-donor ligand and 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen) as a chelating N-donor ligand and NiCl2.6H2O as a source for Ni ions. The crystal structures of 1 and 2 form discrete complexes in which extensive π−π stacking interactions between aromatic rings of the N-donor ligands resulted in the formation of one dimensional (1D) chain-like structures. The chains are connected by hydrogen bonds to expand the structures into 2D-supramolecular networks. Hirshfeld surface analysis and Density Functional Theory (DFT) calculations were included to rationalize the relative strength of the π-stacking assemblies observed in both complexes. [ABSTRACT FROM AUTHOR]

In vitro antiproliferative activities have been explored in coordination polymers of Mn(II) and Zn(II) involving energetically significant structure-guiding H-bonded synthons with cyclic tetrameric {(3-Ampy)2(H 2 O)2} and {(H 2 O)4 assemblies. [Display omitted] Two new coordination polymers of Mn(II) and Zn(II) viz. {[Mn(µ-tp)(3-Ampy) 2 (H 2 O) 2 ]2(3-Ampy)·2(H 2 O)} n (1) and {[Zn(µ-succ)(3-Ampy) 2 ]·2H 2 O} n (2) (tp = terephthalate, 3-Ampy = 3-aminopyridine, succ = succinate) have been synthesized and characterized using elemental and spectroscopic analyses, TGA and single crystal X-ray diffraction techniques. Uncoordinated 3-AMpy and water molecules of the polymeric co-crystal hydrate 1 are involved in the formation of cyclic tetrameric {(3-Ampy)2(H 2 O)2} assembly which provide rigidity to the structure. The presence of guest 3-Ampy and water molecules in the voids of supramolecular Mn(II) host tetramer in 1 provides additional reinforcement to the crystal structure. The lattice water molecules of 2 are aggregated via non-covalent interactions to form discrete cyclic {(H 2 O)4} tetrameric clusters in the crystal structure. Density functional theory (DFT), non-covalent index (NCI) plot and quantum theory of atoms in molecules (QTAIM) computational analyses reveal that the supramolecular H-bonded cyclic tetrameric structure-guiding synthon in 1 and the (H 2 O) 4 cyclic water clusters in 2 have significant energetic contribution towards the stability of the polymers. In vitro anticancer activities of the compounds considering trypan blue and apoptosis assays revealed that the compounds induce concentration dependent cytotoxicity in Dalton's lymphoma (DL) cancer cells with nominal effects in normal peripheral blood mononuclear cells (PBMC) cells. Comparative analysis reveals that compound 2 induced higher apoptosis in DL cells; which is well consistent with the trypan blue exclusion assay. Molecular docking and pharmacophore modelling studies of the compounds reveal that the compound 2 significantly interacts with the antiapoptotic proteins to establish structure activity relationship (SAR). [ABSTRACT FROM AUTHOR]

[Display omitted] • Pyridinedicarboxylato bridged coordination polymers of Cu(II). • Unconventional C H⋯π(carbonyl) and intramolecular O⋯C π-hole interactions. • Semi-coordination (regium) Cu-O axial bonds. • NCI plot and QTAIM computational tools. • In vitro Antiproliferative potential in Dalton's Lymphoma cancer cell lines. Two pyridinedicarboxylato bridged 1D coordination polymers of copper(II) viz.; {[Cu(2,5-PDC)(Hdmpz) 2 ]·H 2 O} n (1) and {[Cu(2,3-PDC)]·10H 2 O} n (2) (where, Hdmpz = 3,5-dimethyl pyrazole, PDC = pyridinedicarboxylate) have been isolated and characterized using TGA, elemental analysis, spectroscopic (IR, electronic) and single crystal X-ray diffraction techniques. Crystal structure analysis of the compounds 1 and 2 reveals that unconventional C H⋯π(carbonyl) and intramolecular O⋯C π-hole interactions provide stability to the crystal structures, respectively. Such C H⋯π(carbonyl) and intramolecular O⋯C π-hole interactions are scarcely reported in the literature. Theoretical calculations have been performed to analyze the unconventional non-covalent interactions observed in the solid-state structures of 1 and 2 using NCI plot and QTAIM computational tools. We have also theoretically explored the semi-coordination (regium) Cu-O axial bonds present in the compound 2. The polymers have been further investigated for potential antiproliferative activities considering cell viability and apoptosis assays against Dalton's lymphoma (DL) cancer cell lines and the results were compared with cisplatin (reference drug) in the same experimental conditions. The compounds significantly induce cytotoxicity in DL cells with nominal cytotoxicity in normal PBMC cells. The molecular doking simulation performed with the antiapoprotic protiens reveals strong binding affinities of the compounds with the active sites of the target proteins. To establish structure activity relationship (SAR), pharmacophore studies have been carried out to investigate the key pharmacophore features of the structures of the compounds responsible for biological activities. [ABSTRACT FROM AUTHOR]

Lanthanide coordination polymers (LnCPs) are influential chemosensors when designed to undergo a detectable change in optical properties upon interacting with target analytes. This work reports interaction of metal ions with LnCPs leading to elicit changes in fluorescence emission intensity, an essential step en route to developing sensitive and selective systems for metal-ion sensing. Towards this goal, solvothermal reaction of 5- Nitroisophthalic Acid (5-NIAH 2) and Ln (NO 3) 3 ⋅xH 2 O produced seven Ln-coordination polymers {[Nd (5-NIA) (5-NIAH) (H 2 O) 2 ]⋅CH 3 CN}n (1), {[Sm (5-NIA) (5-NIAH) (H 2 O) 2 ]⋅CH 3 CN⋅H 2 O}n (2), {[Gd (5-NIA) (5-NIAH) (H 2 O) 2 ]⋅(H 2 O) 2 }n (3), {[Tb (5-NIA) (5-NIAH) (H 2 O) 2 ]⋅CH 3 CN)}n (4), [Dy (5-NIA) (5-NIAH) (H 2 O) 2 ]n (5), [Ho(5-NIA) (5-NIAH) (H 2 O) 2 ]n (6) and [Er 2 (5-NIA) 3 (H 2 O) 3 (CH 3 CN)]n (7) with two-dimensional structures. The as-synthesized polymers are characterized by powder X-ray crystallography, infrared spectroscopy, thermogravimetric analysis, photoluminescence and DFT studies. The luminescence properties of [Tb (5-NIA) (5-NIAH) (H 2 O) 2 ]⋅CH 3 CN)}n (4) is investigated. The CP- 4 is highly sensitive for the detection of Cd2+ exhibiting most intensive fluorescence quenching with the lowest limit of detection. Other metal ions, including Co2+, Fe3+, Fe2+ and Pb2+ are also detected demonstrating the range of sensing capabilities. Seven new coordination polymers were synthesized and Tb- polymer has been utilized for efficient chemical sensing of Cd2+ ion. [Display omitted] • Seven 2D coordination polymers containing 5-nitroisophthalate linker are reported. • All coordination polymers crystallize in the triclinic crystal system with space group P-1. • DFT studies reveals existence of antiparallel stacking and pnictogen π-hole bonding interaction in CPs. • The luminescence properties of [Tb (5-NIA) (5-NIAH) (H 2 O) 2 ]·CH 3 CN)}n have been investigated. • [Tb (5-NIA) (5-NIAH) (H 2 O) 2 ]·CH 3 CN)}n is highly sensitive for the detection of Cd2+. [ABSTRACT FROM AUTHOR]

• Two new Holmium CPs 1 and 2 , containing 5-hydroxyisophthalate linker have been synthesized and characterized. • Both the CPs show 1D linear ladder shaped extension with the linkage having the backbone of hip2− moieties. 1 is mononuclear and 2 is isophthalate bridged tetranuclear structure. • Hydrogen bonding in both the CPs 1 and 2 contribute to the extensive 3D supramolecular framework. • DFT studies reveal the existence of strong antiparallel and parallel stacking interactions in 1 and 2, respectively. Two new Ho(III)-5-hydroxyisophthalates with the formulae; {[Ho(hip)(H 2 O) 5 ].(NO 2).H 2 O} n (1) and {[Ho 4 (hip) 4 (H 2 O) 20 ].2(hip2−).8H 2 O} n (2) were solvothermally synthesized by self-assembly of Ho(III)-nitrate with rigid 5-hydroxyisophthalic acid (H 2 hip) linker. The coordination polymers (CPs) 1 and 2 crystallize in monoclinic P 2 1 / c and P 2 1 / n space groups, respectively. Both the CPs 1 and 2 , shows 1D linear ladder shaped extension with the linkage having the backbone of hip2− moieties. In the both CPs 1 and 2, the Ho centers are nine coordinated. In CP 1 , Ho shows distorted tricapped trigonal prismatic geometry while in CP 2 , four Ho centres display three different geometries (monocapped square antiprismatic geometry around Ho1 and Ho3; distorted tricapped trigonal prismatic geometry around Ho2 and; distorted monocapped square antiprismatic geometry around Ho4). The organic linker hip2− exhibits only one coordination mode (μ 2 -κO,O:κO,O). Theoretical calculations have been performed to analyze the antiparallel and parallel π stacking interactions observed in the solid-state structures of coordination polymers 1 and 2 , respectively. The DFT study is focused on the energetic features of the π-stacking, the influence of the ligand coordination to Ho upon the π-stacking strength and their characterization by the noncovalent interaction plot (NCIplot) index computational tool. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two new hg and one new mn complexes with the N' -(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide ligand have been synthesized and characterized. • The importance of spodium bonding in the solid state of hg complexes has been demonstrated both experimentaly and theoretically. • Hirshfeld surface data analysis show a great importance of spodium bonds and metal–halogen···halogen–metal interactions. • Supramolecular assemblies and σ- -hole interactions have been studied by means of DFT calculations. In this work we report on crystal structures of a heteroleptic coordination polymer [Hg 2 (HL)Cl 4 ] n (1) where the nitrogen atom of the peripheral pyridine fragment is linked to another HgCl 2 molecule and two discrete mononuclear heteroleptic complexes [Hg(HL)I 2 ] (2) and [Mn(HL)Cl 2 ]·MeOH (3 ·MeOH), which were obtained through self-assembling of N' -(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide (HL) with HgCl 2 , HgI 2 or MnCl 2 , respectively. HL coordinates the HgII salts in its keto-form, while MnCl 2 is chelated by a zwitterionic form of HL confirmed by the solid state IR spectroscopy. The studied here ligand molecule has a tendency to involve the 4-pyridyl nitrogen atom in coordination bonding which is correlated with the ability to transfer the electric charge and production of a zwitterionic form. The crystal structure and Hirshfeld surface data analysis show a great importance of spodium bonds and metal–halogen⋯halogen–metal interactions. A prominent consequence of lack of σ- or π-hole interactions in case of MnII ion is the isolation of metal center from the external contacts. Apart form this in 3 ·MeOH the halogen⋯halogen interactions are absent. It seems that the σ- or π-hole regions formed at the HgII cation in 1 and 2 favor the participation of coordinated Cl or I atoms in the M–Hal⋯Hal ' –M ' halogen⋯halogen interactions, whereas in complex 3 ·MeOH there are no metal or halogen centered σ-hole interactions. Thus, the 1D coordination polymer in 1 is stabilized by the Hg⋯Cl spodium bonding. Additionally, the observed intermolecular halogen⋯halogen interactions in 1 provide cross-linking of the 1D coordination polymers, yielding a 2D supramolecular double-layered sheet. In 2 an additional contact between halogen and mercury atoms results in a dimeric unit. These dimers are linked into a 1D polymer by halogen⋯halogen interactions between metal bounded iodine atoms. The DFT theoretical studies were applied to analyze the Hg⋯X non-covalent spodium interactions that govern the formation of the 1D polymeric structure in 1 and self-assembled dimers in 2. This work unveils indispensable role of spodium bonding and other non-covalent interactions in the HgII-derived complexes with N' -(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide, which predominantly drive formation of extended architectures in comparison to the MnII-derivative. [Display omitted] [ABSTRACT FROM AUTHOR]

• Two new cobalt and cerium complexes with π-extended organic ligands have been synthesized and characterized. • Cerium complex with 1,10-phenanthroline-2,9-dicarboxylate (PDA) and water form of left-handed and right-handed helices. • Cobalt complex with PDA and 1,10-phenanthroline (phen) has a strong tendency to form antiparallel π-stacking assemblies. • Supramolecular assemblies studied by means of DFT calculations. Two new metal–organic complexes, [Co(phen)(PDA)H 2 O]·CH 3 CN·H 2 O (1), (phen = 1,10-phenanthroline, PDA = 1,10-phenanthroline-2,9-dicarboxylate) and [Ce 2 (PDA) 3 (H 2 O) 2 ]·3H 2 O (2) have been synthesized and characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray crystallography. Structural characterization by single-crystal X-ray diffraction shows that in 1 the cobalt ion forms a discrete seven-coordinated complex with a distorted pentagonal bipyramidal geometry around the metal centre. These discrete units are further packed into 3-D supramolecular assemblies by different kinds of the noncovalent interactions. Complex 2 consists of a 1D coordination polymeric structure with the cerium ion coordinated by PDA and water in the form of left-handed and right-handed helices. The extended aromatic systems of PDA and phen have a strong tendency to establish antiparallel π···π stacking interactions generating interesting assemblies in the solid state of 1. They have been studied theoretically using DFT calculations and characterized by means of the quantum theory of "atoms-in-molecules" (QTAIM) and the noncovalent interaction (NCI) plot methods. This study is useful to understand in more detail the energetic and structural stability of these categories of metal-organic complexes. The results reported herein suggest that the antiparallel π-stacking interactions involving the neutral and, in principle innocent, phen auxiliary ligand are energetically very relevant in the solid state of 1. This manuscript reports the synthesis, X-ray characterization and DFT studies of two new metal–organic complexes, [Co(phen)(PDA)H 2 O]·CH 3 CN·H 2 O (1), (phen = 1,10-phenanthroline, PDA =1,10-phenanthroline-2,9-dicarboxylate) and [Ce 2 (PDA) 3 (H 2 O) 2 ] ·3H 2 O (2). The energetic features of the antiparallel stacking and H-bonding interactions are reported and discussed in detail. [Display omitted] [ABSTRACT FROM AUTHOR]

• Three new CPs of La(III), Pr(III) and Nd(III), decorated with Succinate linker have been reported. • All Ln(III) centres in Ln-succinates 1-3 exhibit ten coordinated bicapped square antiprismatic geometry which is not known in the previously reported Ln(III)–succinates without auxillary coligands. • DFT studies reveal that compound 3 forms interesting water channels in the solid state. • Artificial water channels [10.1016/j.coche.2019.06.007] are synthetic molecules that aim to mimic the structural and functional features of biological water channels (aquaporins). • The CP 3 reported herein can be considered as a potential new class of artificial water channel. Three new coordination polymers have been assembled by self-assembly of lanthanide(III) ions and succinic acid in dimethylformamide–water (DMF-H 2 O) mixed solvent having formulae; {[Ln(suc) 1.5 (H 2 O) 2 ]•xH 2 O} n ; (1) , (2) and (3) [Where Ln = La (1), Pr (2) and Nd (3), suc = succinate dianion; x = 2 for CP 1 , x = 1 for CP 2 and x = 4 for CP 3 ]. In all three coordination polymers (CPs) 1-3, the Ln(III) centres are ten coordinated with bicapped square antiprismatic geometry (SAPRS-10). Crystallographic analysis reveals that CPs 1-3 crystallize in triclinic system P ¯1 space group. The linker succinic acid displays two different bonding modes: (μ 2 - κ 4, η 2: η 2) and (μ 4 - κ 6, η 1: η 2: η 2: η 1). All CPs 1-3 are isostructural and isomorphous. The two Ln centres in CPs 1-3 are bridged together through succinate anions via (μ 4 - κ 6, η 1: η 2: η 2: η 1) mode forming dinuclear (Ln 2 O 18) Secondary building unit (SBU) which are extended infinitely to generate one-dimensional chains. These 1D chains are further extended along the b -axis to form two-dimensional layered structures via (μ 2 - κ 4, η 2: η 2) mode and finally three-dimensional network. In case of Nd, the quality of the crystal allows to locate a major number of lattice water molecules (x = 4) than in the other two complexes and, remarkably, the formation of water channels can be realized and studied. It has been analyzed using DFT calculations combined with the molecular electrostatic potential (MEP) surfaces, the quantum theory of "atoms-in-molecules" QTAIM and non–covalent interaction index (NCIplot) analyses. [Display omitted] [ABSTRACT FROM AUTHOR]