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Four lead(II) complexes featuring pyrazoylisonicotinoylhydrazone ligand paired with various anionic co-ligands (azido, thiocyanato, nitrito, and nitrato) were synthesized and thoroughly examined using structural, analytical, and spectroscopic techniques. These ligands, in their mono-deprotonated state, bind to the lead(II) ion in a tridentate manner through two nitrogen atoms and one oxygen atom. Single-crystal X-ray crystallography revealed the capacity of these molecular complexes to form larger aggregates influenced by the nature of the anion attached to the metal center. In every complex, the lead atom adopts a hemidirectional coordination environment, making it geometrically suited for tetrel bond formation. The crystal structures demonstrate that lead atoms engage in notably short interactions with nitrogen atoms, distances that are shorter than the sum of their van der Waals radii yet exceed the sum of their covalent radii. These tetrel bonds play a pivotal role in weaving the monomeric into self-assembled dimers or extended supramolecular 1D polymers. The formation and characteristics of these intriguing supramolecular structures observed in the solid state of each complex were further explored and validated through density functional theory (DFT) calculations and several computational tools like MEP, NCIPlot, QTAIM, and ELF methods. [ABSTRACT FROM AUTHOR]

Treatment of the [AuCl(tetrahydrothiophene)] complex with 4-chloro-2-iodo-1-isocyanobenzene furnished the gold(I) compound [AuCl(CNC6H3-4-Cl-2-I)] (1). In the crystal structure of 1, the linear C–Au–Cl group is subject to the solid-state head-to-tail pairing, which is determined by the aurophilic Au⋯Au and the rare π-holeCN⋯Cl interactions. These two types of structure-determining interactions are complementary to each other, and the system of Au⋯Au and CCN⋯Cl contacts accomplishes a 2D extended ladder-type architecture. In addition, the terminal I-atoms are involved in the three-center halogen bonding. Density functional theory calculations, employing a set of computational tools, verified the role of Au⋯Au and π-holeCN⋯Cl noncovalent bonds in the spectrum of noncovalent forces. [ABSTRACT FROM AUTHOR]

In this manuscript, we have examined the CSD (Cambridge Structural Database) to investigate the relative ability of Te and I (in practice, the heaviest chalcogen and halogen atoms) in di- and tri-iododiorganyltellurium(IV) derivatives to establish σ-hole interactions. The geometry around the Te(IV) in this type of compound is trigonal bipyramidal where the stereoactive lone pair at Te(IV) occupies one of the equatorial positions. In the solid state, Te(IV) tends to form pseudo-octahedral coordination by establishing strong noncovalent interactions opposite to the two covalent bonds of the equatorial plane. Such contacts can also be classified as chalcogen bonds following the recommendation of the International Union of Pure and Applied Chemistry (IUPAC). Such contacts have been analyzed energetically in this work using density functional theory (DFT) calculations, rationalized using molecular electrostatic potential (MEP) surface analysis and characterized using a combination of the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction plot (NCIplot) computational tools. Finally, the observation of halogen bonds and type I halogen···halogen contacts is also emphasized and compared to the chalcogen bonds. Energy decomposition analysis has also been performed to compare the physical nature of chalcogen, halogen and type I interactions. [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]

Two new dinuclear cobalt(II) complexes, [(H2O)CoIIL1(μ-O2CR1)CoII(NCS)] (1) and [(DMSO)CoIIL2(μ-O2CR2)CoII(NCS)] (2) (H2L1 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol), H2L2 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-ethoxyphenol), R1CO2H = 3-methyl-4-nitrobenzoic acid, and R2CO2H = 4-methyl-3-nitrobenzoic acid), were synthesized using multidentate N,O-donor ligands with two pockets. Each complex was characterized using single crystal X-ray diffraction and spectral analysis. The noncovalent interactions were analyzed using density functional theory (DFT) calculations. In addition, the optical properties of the complexes were studied with a focus on the band gaps. Both complexes were utilized for the fabrication of semiconducting Schottky devices. [ABSTRACT FROM AUTHOR]

The series of substituted 1,2,4-selenodiazolium tetraphenylborate complexes were synthesized via cyclization between 2-pyridylselenylchloride, followed by the anion metathesis, and fully characterized. The utilization of tetraphenylborate anion, a strong π-electron donor via its phenyl rings, promoted the formation of assemblies exhibiting selenium–π interactions. The chalcogen bonding (ChB) interactions involving the π-systems of the tetraphenylborate anion were studied using density functional theory (DFT) calculations, where "mutated" anions were used to estimate the strength of the Se···π chalcogen bonds. Moreover, molecular electrostatic potential (MEP) surfaces were used to investigate the electron-rich and poor regions of the ion pairs. The quantum theory of atoms-in-molecules (QTAIM) and the noncovalent interaction (NCI) plot methods based on the topology of the electron density were used and combined to characterize the ChBs. The investigation reported herein disclosed that the formation of symmetrical dimers can be broken by the introduction of a stronger π-acceptor and, consequently, forming stronger Se···π contacts with selenodiazolium cations. [ABSTRACT FROM AUTHOR]

The chalcogen bond has been recently defined by the IUPAC as the attractive noncovalent interaction between any element of group 16 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. Commonly used chalcogen bond donor molecules are divalent selenium and tellurium derivatives that exhibit two σ-holes. In fact, the presence of two σ-hole confers to the chalcogen bonding additional possibilities with respect to the halogen bond, the most abundant σ-hole interaction. In this manuscript, we demonstrate that selenoxides are good candidates to be used as σ-hole donor molecules. Such molecules have not been analyzed before as chalcogen bond donors, as far as our knowledge extends. The σ-hole opposite to the Se=O bond is adequate for establishing strong and directional ChBs, as demonstrated herein using the Cambridge structural database (CSD) and density functional theory (DFT) calculations. Moreover, the effect of the metal coordination of the selenoxide to transition metals on the strength of the ChB interaction has been analyzed theoretically. The existence of the ChBs has been further supported by the quantum theory of atoms in molecules (QTAIM) and the noncovalent interaction plot (NCIPlot). [ABSTRACT FROM AUTHOR]

The series of benzylic-substituted 1,2,4-selenodiazolium salts were prepared via cyclization reaction between 2-pyridylselenyl chlorides and nitriles and fully characterized. Substitution of the Cl anion by weakly binding anions promoted the formation supramolecular dimers featuring four center Se2N2 chalcogen bonding and two antiparallel selenium⋯π interactions. Chalcogen bonding interactions were studied using density functional theory calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of atoms-in-molecules (QTAIM), and the noncovalent interaction (NCI) plot. The investigations revealed fundamental role of the selenium⋯π contacts that are stronger than the Se⋯N interactions in supramolecular dimers. Importantly, described herein, the benzylic substitution approach can be utilized for reliable supramolecular dimerization of selenodiazolium cations in the solid state, which can be employed in supramolecular engineering. [ABSTRACT FROM AUTHOR]

The term matere bond has been recently used to refer to an attractive noncovalent interaction between any element of group 7 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. The utilization of metals such as σ-hole donors is starting to attract the attention of the scientific community. In this manuscript, a comparison between matere bonds and well-known σ-hole interactions (halogen and chalcogen bonds) is carried out using three X-ray structures, retrieved from the Cambridge structural database (CSD), and density functional theory calculations (DFT). The novelty of this work resides in the utilization of a neutral Re(VII) system as the matere bond donor and multivalent chalcogen and halogen donors. In fact, as far as our knowledge extends, the description of σ-hole interactions in Se(VI) is unprecedented in the literature. The σ-hole interactions in Re(VII), Se(VI) and Cl(VII) electron acceptors are analyzed and compared using several computational tools. [ABSTRACT FROM AUTHOR]

The vital role of triel bonding (TrB) has been highlighted in two new thallium compounds i.e. Tl+[{(4-C2H5)C6H4O}2PS2]2− (1) and Tl[{(4-CH(CH3)2)C6H4O}2PS2]2 (2). These new compounds have been characterized by elemental and spectral analyses. The crystal structures of 1 and 2 belong to the monoclinic and triclinic systems with space groups P21/c and P1¯, respectively. Interestingly, compound 1 exists in ionic form and is stabilized through intramolecular Tl⋯S (TrBs) interactions wherein the thallium atom is symmetrically positioned in the cleft of the ligand with longer Tl–S distances. In compound 2, the thallium atom is coordinated to one sulfur atom and the other sulfur atom participates in TrB interaction. Both compounds also exhibit intermolecular Tl⋯S, Tl⋯π (TrBs), and C–H⋯Tl (anagostic) interactions, which assist to form unique supramolecular architectures owing to large size as well as coordinative unsaturation on the thallium. These non-covalent TrB interactions were authenticated by Hirshfeld surface analysis (HSA) and density functional theory (DFT) calculations using the quantum theory of atoms-in-molecules (QTAIM) and non-covalent interaction plot (NCI Plot) index methods. TrBs involving Tl have been scarcely described in the literature; therefore this work provides valuable insight into the importance of these unprecedented TrBs in the solid state. [ABSTRACT FROM AUTHOR]

Two new zinc(II) complexes, [{N(CN)2}Zn(L1)Zn{μ-1,5-N(CN)2}]2 (1) and [{μ-1,5-N(CN)2}{N(CN)2}Zn(L2)Zn{μ-1,5-N(CN)2}]n (2) {H2L1 = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(nitrilomethylidyne)]bis[6-methoxyphenol] and H2L2 = 2,2′-[(2,2-dimethyl-1,3-propanediyl)bis(nitrilomethylidyne)]bis[6-ethoxyphenol]} have been synthesized and characterized. The structures of both complexes have been confirmed by X-ray crystallography. A subtle difference in the aromatic ring of the Schiff base ligand (6-ethoxy in H2L2 and 6-methoxy in H1L1) has a strong influence on the final solid state structure. In addition, the O-atom of the methoxy groups in 1 forms stronger intramolecular spodium bonds with Zn(II) than the O-atom of the ethoxy group in 2. This has been analysed using density functional theory (DFT) calculations and a combination of the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction (NCI) plot index computational tools. [ABSTRACT FROM AUTHOR]

This manuscript combines a search in the Cambridge Structural Database (CSD) and theoretical density functional theory (DFT) calculations to analyse the existence and importance of charge assisted pnictogen and halogen bonds involving halophosphonium cations. Trivalent pnictogen atoms typically have three σ-holes and are able to establish up to three pnictogen bonds (PnBs). In phosphonium salts, the phosphorus atom forms four covalent bonds and, consequently, four σ-holes are located at the extension of these bonds. Therefore, up to four charge assisted PnBs can be formed between these holes and the counterions or any electron rich atom. The covalent bond arrangement around the phosphorus atom is similar to that around tetravalent tetrel atoms and converts into a similar pattern of σ-hole interactions. We have found and described this type of charge assisted pnictogen bond in various halophosphonium crystal structures. Moreover, the competition of charge assisted PnBs with charge assisted halogen bonds (HaBs) has been also studied both theoretically and by analysing the CSD. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new nickel(II) complex of unsymmetrical Schiff base ligand has been synthesized and use it as a metalloligand. • Three new heterometallic nickel(II)-manganese(II) complexes have been synthesized. • All of the complexes have been structurally characterized. • The metalloligand shows variable denticity towards complex formations. • Presence of noncovalent interactions have been observed in all the complexes. An attempt to synthesis complexes of a N 2 O 3 donor unsymmetrical Schiff base ligand, obtained from the condensation of 2,2-dimethyl-1,3-propanediamine with o-hydroxyacetophenone and o-vanillin via modified Edler's method yielded a mononuclear Ni(II) complex, [NiL]·1.5H 2 O·0.5CH 3 OH (1), where H 2 L = N-(α-methylsalicylidene)-N′-(3-methoxysalicylidene)-2,2-dimethyl-1,3-propanediamine. Three heterometallic Ni(II)-Mn(II) complexes, [(NiL) 2 Mn(H 2 O) 2 ](ClO 4) 2 ·2H 2 O (2), [(NiL)MnCl 2 ] (3) and [(NiL)Mn(NCS) 2 (H 2 O)]·[NiL] (4), have been isolated upon reaction of complex 1 with Mn(II) ions in presence respective co-anions, of which two are discrete complexes while third is a co-crystal. Single crystal X-ray crystallography revealed that Ni(II) centre is four coordinated in square planar environment in all complexes, whereas the geometry of Mn(II) centre is distorted octahedral in complexes 2 and 4, and distorted trigonal bipyramidal in 3. Structural differences have been rationalized by density functional theory (DFT) calculations. All the complexes exhibit recurrent π-stacking and C H⋯π motifs in solid state which have been characterized by molecular electrostatic potential (MEP) surface calculations and non-covalent interaction plot. [ABSTRACT FROM AUTHOR]

This manuscript reports the synthesis and X-ray characterization of two octahydro-1H-4,6-epoxycyclopenta[c]pyridin-1-one derivatives that contain the four most abundant halogen atoms (Ha) in the structure with the aim of studying the formation of Ha···Ha halogen bonding interactions. The anisotropy of electron density at the heavier halogen atoms provokes the formation of multiple Ha···Ha contacts in the solid state. That is, the heavier Ha-atoms exhibit a region of positive electrostatic potential (σ-hole) along the C–Ha bond and a belt of negative electrostatic potential (σ-lumps) around the atoms. The halogen bonding assemblies in both compounds were analyzed using density functional theory (DFT) calculations, molecular electrostatic potential (MEP) surfaces, the quantum theory of "atom-in-molecules" (QTAIM), the noncovalent interaction plot (NCIplot), and the electron localization function (ELF). [ABSTRACT FROM AUTHOR]

Indium(III) diaryldithiophosphate complexes have been synthesized and characterized. Complex 1 is further studied by SC-XRD which shows the presence H-bonds, C–H ⋯ π and π ⋯ π interactions which is further analyzed by HSA and DFT calculations using NCI Plot index methods. [Display omitted] Mononuclear aryldithiophosphates of indium(III), In[ S 2 P { OAr } 2 ] 3 ; Ar = (3,5-CH 3) 2 C 6 H 3 (1), (3,4-CH 3) 2 C 6 H 3 (2), (2,5-CH 3) 2 C 6 H 3 (3) and (2,4-CH 3) 2 C 6 H 3 (4), have been synthesized and characterized by elemental analysis, NMR and FT-IR spectroscopy. Single crystal X-ray crystallography reveals that complex 1 belongs to the monoclinic crystal system with the space group P2 1 / c , wherein the indium ion is six fold coordinated with sulfur atoms of the dithiophosphate moiety resulting in a distorted octahedral geometry. Complex 1 contains intermolecular C⋯H, C–H⋯S, C–H⋯ π and π ⋯ π non-covalent interactions that help in attaining the stability of the molecule. A thorough Hirshfeld surface analysis (HSA) has also been carried out to scrutinize the intermolecular non-covalent interactions present within the molecule and the energetic features are evaluated using density functional theory (DFT) calculations. The non-covalent interaction plot (NCI Plot) index and molecular electrostatic potential (MEP) surfaces have also been used to characterize and rationalize the non covalent C–H⋯S, C–H⋯ π and π ⋯ π interactions. [ABSTRACT FROM AUTHOR]

A novel computationally designed-spectrofluorimetric method for the determination of a unique antinarcoleptic drug; modafinil (MDF) in tablets and human plasma was theoretically and experimentally established. Firstly, a density functional theory (DFT) computations were performed to investigate MDF-Tb3+ complex formation and to study the affinity of Tb3+ to MDF in aqueous solution. The computed formation energy of [Tb (MDF) 4 ]3+ (ΔG= −246.0 kcal/mol) assured the ability of Tb3+ to recognize MDF in water and proved the strong nature of the Tb3+–O coordination bonds in addition to some contribution from inter-ligand hydrophobic interactions. Hence, a spectrofluorimetric method was optimized and validated depending on MDF quenching effect on Tb3+ fluorescence via fluorescence resonance energy transfer from Tb3+ to MDF. The formed [Tb (MDF) 4 ]3+ complex was measured at λ ex. 222 nm/ λ em. 497 nm against a reagent blank. The Tb3+ fluorescence was significantly reduced upon addition of MDF (linearity range= 0.5–20.0 μg/mL). Detection and quantification limits were 0.129 and 0.391 μg/mL, respectively. Good recoveries (97.47–101.92%) were obtained upon application of the proposed method for the assessment of the target drug in bulk powder, tablets and plasma. According ICH guidelines, the results of the established method were statistically analyzed and validated. [Display omitted] • The 1st study introduces a computationally designed-spectrofluorimetric method for modafinil analysis. • Modafinil-terbium interaction was explored via density functional theory computations. • Modafinil quenching effect on Tb3+ fluorescence was experimentally studied. • Assessment of modafinil in tablets and human plasma was successfully achieved. • Combined computational/experimental approach offers a future concept in drug analysis. [ABSTRACT FROM AUTHOR]

• Findings of both classical (O‒H•••O) and non-classical (C‒H•••O) hydrogen bonding interactions along with anti-parallel π•••π stacking. • Supramolecular networks inside the title complexes comprise the π-stacked self-assemblies analysed by QTAIM and NCI plot. • Presence of very strong ring motifs in agreement with the MEP analysis. • Fabrication of schottky barrier diode and conductivity studies. Two new complexes [Ni(C 7 H 3 NO 5) (C 15 H 11 N 3)]. 4(H 2 O) (1) and [Cu(C 7 H 3 NO 5) (C 15 H 11 N 3)]. 4(H 2 O) (2) have been synthesized using mixed chelating ligands [4-hydroxypyridine-2,6-dicarboxylic acid (chelidamic acid) (C 7 H 5 NO 5) and 2,2′:6′,2′′-terpyridine (C 15 H 11 N 3)] in aqueous medium. The two complexes were characterized by UV–visible, IR spectroscopy as well as by single-crystal X-ray diffraction analysis. The geometries of both the complexes are distorted octahedral with N 4 O 2 chromophore. The non-covalent interactions found in the solid state architectures of complexes 1 and 2 have been described focusing on π•••π stacking and hydrogen bonding interactions. These non-covalent interactions played an imperative role in building of multi-dimensional supramolecular architectures. These interactions have been explored theoretically by density functional theory (DFT) focusing on the antiparallel π-π stacking in self-assembled dimers and the hydrogen bonding networks mediated by the lattice water molecules. MEP surface calculations combined with QTAIM and NCI plot analysis were used to rationalize and characterize the non covalent interactions involved in the assemblies. The low optical band gaps of the two complexes exhibit semiconducting property leading to potentially fabricate Schottky Barrier Diode. [Display omitted] [ABSTRACT FROM AUTHOR]

Synthesis and structural characterization of decavanadates containing cationic organic moiety. DNA binding ability towards CT-DNA and micellization behaviour with CTAB of the complexes were explored. DFT studies performed to analyze the interactions, structural stability of the compounds in solid state. [Display omitted] • Synthesis, characterization, X-ray structure of three decavanadate containing cationic organic moiety. • DNA binding ability towards CT-DNA was explored. • Complexes exhibit increased solubility on interaction with cationic surfactant CTAB. • DFT, QTAIM studies analysed the effective ion pairs, hydrogen bond interaction responsible for formation of supra molecular assemblies, cohesion, and stability of solid state structures of the compounds. Reported here synthesis, structure, DNA binding ability of three decavanadates complexes containing cationic organic moieties, 2-methylimidazolium (1), 4-dimethylaminopyridinium (2) and protonated 3-pyridiniumcarboxamide (3). Compounds are stable solids, characterized by elemental analyses, spectroscopic, single-crystal X-ray diffraction and theoretical studies. X-ray diffraction analysis indicates, the molecular structures of the compounds are composed of ion pairs formed by decavanadate ion [H 2 V 10 O 28 ]4− and the corresponding cationic organic moieties. Complex 1 composed of decavanadate anion in combination with cationic 2-methylimidazolium and 2 contains decavanadate moiety with counter cation protonated 4-dimethylaminopyridine, two DMSO molecules. The structure of 3 consists of [H 2 V 10 O 28 ]4−, protonated 3-pyridinecarboxamide, two co-crystallized neutral organic moieties with two molecules of water. The effective interaction of the ion-pair and hydrogen bonding interaction resulted in the cohesion, stabilization of solid state structure of the complexes. In solid state, compounds present interesting assemblies through the formation of H-bonds analyzed using DFT calculations and quantum theory of "atoms in molecules" (QTAIM). Interaction of the compounds with CT-DNA studied by absorption and fluorescence spectroscopy, show moderately strong intercalative mode of binding. Additionally micellization behaviour of the complexes using surfactant CTAB was studied by conductance measurements and absorption spectroscopy. The complexes show an increased solubility on addition of the surfactant. [ABSTRACT FROM AUTHOR]