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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 coordination complexes viz. [Mn 2 (μ‑O,O′‑4‑Mebz) 2 (bpy) 2 (μ2‑H 2 O)(4‑Mebz) 2 ] (1) and [Zn(bpy)(pdc)(H 2 O)]·3.5H 2 O (2) (where bpy = 2,2′‑bipyridine, 4‑Mebz = 4‑methyl benzoate and pdc = 2,6‑pyridine dicarboxylate) were synthesized and structurally characterized by single crystal X-ray diffraction, FT-IR, electronic spectroscopy, Thermogravimetric Analysis (TGA) and Powder X-ray diffraction (PXRD) techniques. Complex 1 consists of a dinuclear Mn(II) unit bridged by a solvent water molecule while 2 is a mononuclear complex. The supramolecular assemblies found in the solid state of both complexes have been described. In 2 , several π-stacking interactions modes have been further studied using Density Functional Theory (DFT) calculations. Furthermore, the activity of the complexes against a few pathogenic bacteria has been studied and confirmed. Finally, the antiproliferative activities of both complexes have been studied in T - cell lymphoma cell line by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis assay and molecular docking simulation. Both the complexes exhibit gratifying cytotoxicity through apoptotic cell death with negligible cytotoxicity (~5–10%) in normal cells. It is worth mentioning that Mn(II) and Zn(II) complexes exhibit interaction modes with highly expressed cancer target proteins under study with higher binding affinity and the results are comparable with reference inhibitors. Two new Mn (II) and Zn(II) coordination complexes with =2,2′‑bipyridine, 4‑methyl benzoate and 2,6‑pyridine dicarboxylate as ligands were synthesized and structurally characterized by single crystal X-ray diffraction. Both complex exhibits gratifying cytotoxicity through apoptotic cell death with negligible cytotoxicity (~5–10%) in normal cells. Unlabelled Image • Bipyridine complexes of Mn(II) and Zn(II) are structurally characterized. • Supramolecular assemblies have been studied using theoretical calculations. • The antiproliferative activities have been investigated by apoptosis and molecular docking. • Complexes exhibit interaction modes with cancer target proteins. • Complexes are found active against a few pathogenic bacteria. [ABSTRACT FROM AUTHOR]

• Supramolecular assemblies in coordination compounds of Zn(II). • Parallel and antiparallel nitrile-nitrile contacts. • DFT calculations in combination with NCI plot/QTAIM analysis. • Energetically significant unconventional π(CN)-π and anion-π(nitrile) contacts. • In vitro antiproliferative potential and structure activity relationships. Two new coordination compounds of Zn(II) involving cyanopyridine ligands viz. [Zn(2,6-PDC)(3-CNpy)(H 2 O) 2 ] (1) and [Zn(4-CNpy) 2 Cl 2 ] (2) (2,6-PDC = 2,6-pyridinedicarboxylate, 3-CNpy = 3-cyanopyridine, 4-CNpy = 4-cyanopyridine) have been synthesized and characterized using elemental analysis, TGA, spectroscopic (FT-IR, electronic and 1H-NMR) techniques and single crystal XRD. Crystal structure analyses of 1 and 2 unfold the presence of unusual π(CN)-π interactions which provide stability to the layered assemblies of the compounds. Anion-π with parallel nitrile–nitrile interactions in 1 and unconventional anion-π(nitrile) with antiparallel nitrile-nitrile interactions in 2 also contribute to the stability of the crystal structures. Antiparallel CO⋯CO interactions give additional reinforcement to the crystal structure of 1. DFT calculations in combination with MEP surface and NCI plot/QTAIM analyses on different self-assembled supramolecular dimers of the compounds revealed that the unusual CN···π interactions in 1 and Chlorine-π(nitrile) in 2 are energetically significant. The studies also reveal that both H-bonding and π-stacking interactions are energetically important for the stability of the compounds. Compounds 1 and 2 mediated anticancer evaluation on Dalton's lymphoma (DL) cancer cells has been explored considering cytotoxicity and apoptosis assays. The compounds induce significant concentration dependent cytotoxicity in DL cells with negligible effects on normal PBMC cells. Molecular docking studies reveal that the compounds effectively interact with the active sites of antiapoptotic proteins which are actively involved in cancer progression. Pharmacophore features of the structures of the compounds have been finally identified to establish the structure activity relationships (SAR). [Display omitted] [ABSTRACT FROM AUTHOR]

Anticancer activities considering cytotoxicity, apoptosis and docking have been explored in Mn(II) and Cu(II) compounds of pyridinedicarboxylates involving enclathrated Mn(II)(H 2 O) 6 guests and unusual Cu⋯O bonding interactions. [Display omitted] Two new coordination compounds of Mn(II) and Cu(II) involving 2,6-pyridinedicarboxylate viz. [Mn 3 (2,6-PDC) 4 (H 2 O) 4 ][Mn(H 2 O) 6 ]·8H 2 O (1) and [Cu(2,6-PDC)(H 2 O)(4-CNpy)]·H 2 O (2) (2,6-PDC = 2,6-pyridinedicarboxylate, 4-CNpy = 4-cyanopyridine) have been synthesized at room temperature. Compound 1 crystallizes as a co-crystal hydrate of Mn(II); whereas compound 2 is a mononuclear compound of Cu(II). Crystal structure analysis of 1 unfolds the presence of Mn(II)(H 2 O) 6 guests within the supramolecular host cavities formed by anionic complex moieties and lattice water molecules. The lattice water molecules of the compounds 1 and 2 are involved in the formation of (H 2 O) 2 cores which are enclathrated in the supramolecular host cavities. Furthermore, the unconventional anion⋯π, antiparallel CN⋯CN, CO⋯CO, CR⋯CR (CR: chelate ring) and Cu⋯O bonding interactions observed in compound 2 play crucial role to the stability of the crystal structure. Theoretical calculations confirm that the H-bonding network in 1 and anion-π, unconventional Cu···O bonds, antiparallel CO···CO along with CR···CR interactions in 2 play crucial roles in the solid state stability of the compounds. In vitro anticancer activities of the compounds considering cell viability and apoptosis assays against Dalton's lymphoma (DL) cancer cell lines reveal that the compounds induce considerable cytotoxicity in DL cells with negligible cytotoxicity in normal PBMC cells. Lactate dehydrogenase (LDH) leakage assay also unfolds the release of LDH from DL cells to extracellular space suggesting the irreversible cell death with cell membrane damage. The molecular docking simulations of the compounds further demonstrate the structure activity relationships involving the active sites of some important antiapoptotic proteins. [ABSTRACT FROM AUTHOR]

In vitro antiproliferative activities have been explored in pyrazole-based Co(II) and Cu(II) compounds involving unusual double anion–π, C H⋯π(chelate) and C H⋯π(carbonyl) contacts. [Display omitted] Two coordination compounds of Co(II) and Cu(II) viz. [Co(2,6-PDC)(Hdmpz) 3 ]·H 2 O (1) and [Cu(2,6-PDC)(Hdmpz) 2 ] (2) (2,6-PDC = 2,6-pyridinedicarboxylate, Hdmpz = 3,5-dimethylpyrazole) have been synthesized and characterized using single crystal XRD, elemental analysis, TGA, electronic, FT-IR and 1H NMR spectroscopy. Crystal structure analysis of 1 and 2 reveals the presence of supramolecular assemblies involving various non-covalent interactions. The crystal structure of 1 is stabilized by a structure guiding hydrogen bonded synthon involving the lattice water molecules and unusual double anion–π interactions involving the carboxylate moieties of 2,6-PDC. Unconventional C H⋯π(carbonyl) and C H⋯π(chelate) contacts involving carbonyl moiety and the chelate ring of 2,6-PDC observed in the crystal structure of 2 also provide rigidity to the layered assemblies. Such unconventional C H⋯π contacts involving carbonyl moiety and chelate ring of 2,6-PDC are scarcely explored. DFT calculations in combination with QTAIM and NCI Plot analyses have been performed on supramolecular dimers of the compounds to explore the energetic features of the self-assembled dimers. The large dimerization energies of the dimers indicate the significance of these non-covalent interactions in governing solid state stabilities of the compounds. Antiproliferative evaluation of the compounds considering cell cytotoxicity and apoptosis assays revealed that the compounds induced significant concentration dependent cytotoxicity in Dalton's lymphoma (DL) cancer cells with nominal effects on normal PBMC cells. Molecular docking and pharmacophore modelling studies of the compounds have been further carried out to establish the structure activity relationship (SAR). [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]

• Pyrazole- based isostructural coordination compounds. • Unconventional charge assisted hydrogen bonded (CAHB) assemblies. • Unusual O···O dichalcogen bonding interactions. • DFT, MEP surface, QTAIM, NCI plot and Molecular docking. • Cell cytotoxicity and apoptosis assays in Dalton's Lymphoma cancer cell lines. Two new isostructural coordination compounds of Ni(II) and Mn(II) viz. [Ni(H 2 O) 4 (Hdmpz) 2 ]ADS (1) and [Mn(H 2 O) 4 (Hdmpz) 2 ]ADS (2) (where, Hdmpz = 3,5-dimethylpyrazole, ADS = anthraquinone-1,5-disulfonate) have been synthesized in aqueous medium at room temperature and characterized them using elemental analysis, TGA, FT-IR, electronic spectroscopy and single crystal X-ray diffraction techniques. Coordination compounds involving ADS anions in the crystal lattice are scarcely reported in the literature. Crystal structure analysis reveals the presence of unconventional O···O dichalcogen bonding interaction between the O-atoms of neighbouring ADS moieties of the compounds. Aromatic π-stacking and unusual charge assisted O‒H···O and C‒H···O hydrogen bonds (CAHBs) are also involved in the stabilization of the crystal structures. Theoretical calculations have been performed to analyze the CAHBs, π-stacking and O···O dichalcogen bonding interactions observed in the solid-state structures of 1 and 2 using DFT calculations, MEP surface analysis, QTAIM and NCI plot index computational tools. The relatively larger interaction energy observed for Ni(II) compound can be attributed to the higher contribution of the CAHBs than that for the Mn(II) complex. The energy associated to the O···O dichalcogen bonding interaction is small (0.6 kcal/mol) and comparable with the weak C‒H···O contact observed in compound 2. In vitro antiproliferative activities of the compounds considering cell cytotoxicity and apoptosis reveal the cytotoxic potential of the compounds in Dalton's Lymphoma (DL) cancer cells with negligible cytotoxicity in normal PBMC cells. Molecular docking simulation of the compounds with antiapoptotic proteins reveals significant affinity of the compounds with the active sites of the antiapoptotic proteins. [Display omitted] [ABSTRACT FROM AUTHOR]

Synthesis, supramolecular assemblies, in vitro antiproliferative activities and structure activity relationships of phenanthroline-based 2,6-pyridinedicarboxylato Cu(II) and Ni(II) compounds were investigated, including cell cytotoxicity, apoptosis assay, molecular docking and pharmacophore studies. [Display omitted] Two new coordination compounds of Cu(II) and Ni(II), viz. [Cu 2 (phen)(μ-2,6-PDC)(2,6-PDC)(H 2 O) 2 ]·4·.5H 2 O (1) and [Ni(phen)(2,6-PDC)(H 2 O)]·2H 2 O (2) (phen = 1,10-phenanthroline; 2,6-PDC = 2,6-pyridinedicarboxylate), have been synthesized under ambient conditions and further characterized using single crystal X-ray diffraction, FTIR, electronic spectroscopy, thermal and elemental analysis. The compound 1 is a 2,6-PDC bridged dinuclear Cu(II) compound, whereas compound 2 crystallizes as a mononuclear Ni(II) compound. Crystal structure analysis and DFT calculations reveal that the non-covalent cooperative π-stacking interactions involved in the supramolecular association of the compounds are energetically significant. In vitro antiproliferative activities of the compounds have been investigated with the Dalton's Lymphoma (DL) malignant cancer cell line using MTT cell viability and apoptosis assays. Both the compounds exhibit significant concentration dependent cell cytotoxicity and apoptotic cell death in DL cancer cells, with nominal effects for normal healthy PBMC cells. A decrease in the MMP (mitochondrial membrane potential) and a rapid increase of the ROS (reactive oxygen species) levels in DL cells corroborate the apoptotic cell death induced by the compounds. To support the observed wet lab cytotoxicity in DL cancer cells, we have also carried out in silico molecular docking studies of the compounds with the active sites of antiapoptotic BCL family proteins. Both the Cu(II) and Ni(II) compounds exhibit significant interaction modes with the BCL family cancer target proteins. Pharmacophore features of the structures of the compounds have been identified to establish a structure activity relationship (SAR). [ABSTRACT FROM AUTHOR]

• Phenanthroline-based coordination compounds of Ni(II). • Energetically significant cooperative π-stacked assemblies. • Unconventional fumarate-water-nitrate and infinite nitrate water clusters. • DFT calculations and Structure Activity Relationship. • Apoptosis assay in Dalton's Lymphoma cancer cell lines. Two new Ni(II) coordination complexes involving fumarate and 1,10-phenathroline viz.; [Ni 2 (phen) 2 (µ-fum)(H 2 O) 6 ](fum)·6H 2 O (1) and [Ni(phen) 2 (H 2 O) 2 ](0.5 fum)(NO 3)·4H 2 O (2) (fum = fumarate, phen = 1,10-phenanthroline) have been isolated in aqueous medium at room temperature. Crystal structure analyses of the compounds reveal the presence of cooperative (π–π) 2 /(π–π) 1 /(π–π) 2 stacked ternary assemblies which provide stabilities to the layered architectures. The lattice water and the large counter anions in the lattice of the compounds are involved in the formation of unconventional discrete cyclic fumarate-water, fumarate-water-nitrate clusters and infinite nitrate-water 1D chains that are very scarcely reported in the literature. The energetically significant π-stacked dimers observed in the biologically relevant ternary assemblies of the crystal structures are further studied theoretically using DFT calculations and NCI plot index computational tools. DFT calculations reveal that the cooperative (π–π) 2 binding mode of compound 1 is energetically more significant than (π–π) 1 Moreover, the study also reveals that for the equivalent cooperative (π–π) 1 stacking interactions in both the structures, the energy is unexpectedly higher for compound 2 than that observed for compound 1. Both the compounds induce significant cytotoxicity in Dalton's lymphoma (DL) cancer cells by inducing apoptotic cell death with negligible cytotoxicity in normal cells. Decrease in the mitochondrial membrane potential (MMP) of DL cells after treatment with the compounds also corroborates the apoptotic cell death. The molecular docking and pharmacophore features reveal that the compounds interact and accommodated well with the active sites of anti-apoptotic proteins. Phenanthroline-based Ni(II) compounds involving unconventional discrete fumarate-water clusters and infinite nitrate-water chains with energetically significant and biologically relevant cooperative (π-π) 2 /(π-π) 1 /(π-π) 2 ternary assemblies. [Display omitted] [ABSTRACT FROM AUTHOR]

• Phenanthroline-based coordination compounds of Ni(II) and Cu(II). • Unconventional enclathration of guest adipic acid and regium-π(chelate) contacts. • Energetically significant antiparallel π-stacked ternary assemblies. • DFT calculations and NCI plot computational analysis. • In vitro antiproliferative potential in dalton's lymphoma cancer cell lines. Two Ni(II) and Cu(II) coordination compounds viz. [Ni(phen) 3 ](0.5adp)(2NO 3)·4.5H 2 O (1) and [Cu 4 (phen) 4 (H 2 O) 2 (OH) 4 ]4NO 3 ·2H 2 O (2) (where, phen = 1,10-phenanthroline and adp = adipic acid) have been isolated in aqueous medium and characterized by single crystal XRD, TGA, elemental analysis and spectroscopic techniques (FT-IR and electronic). Crystal structure analysis of compound 1 reveals the unconventional enclathration of adp moieties in the tetrameric supramolecular host cavities via O(adp)···π and C–H···π interactions. The formation of discrete [(NO 3) 4 (H 2 O) 10 ]4− cores in 1 and unusual enclathration of the nitrate water clusters in the supramolecular host cavity of 2 provide additional reinforcement to the layered assemblies. DFT calculations and NCI plot computational tools have been employed to investigate the energetically significant enclathrated adp moieties in supramolecular host cavities of 1 and the antiparallel π-stacked ternary assemblies involving regium-π(chelate) interaction in 2. To the best of our knowledge, this is the first report of enclathration of adipic acid, a long chain aliphatic dicarboxylic acid; and non-covalent regium-π bonding interaction involving chelate ring in metal organic compounds. Finally, the compounds have been screened for in vitro antiproliferative activities in Dalton's Lymphoma (DL) cancer cell lines considering cell cytotoxicity, apoptosis and molecular docking. The compounds exhibit considerable cytotoxicity in DL cells with nominal effects in healthy normal PBMC cells. The docking study reveals the effective binding affinity of the compounds with the active sites of BCL family antiapoptotic proteins. Unconventional enclathration of guest adipic acid and Energetically significant π-stacked ternary assemblies involving unusual regium-π(chelate) contacts in phenanthroline-based Ni(II) and Cu(II) compounds considering cytotoxicity, apoptosis and molecular docking [Display omitted]. [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]

Werner type clathrate of Ni(II) involving guest benzoates and Cu(II) phenanthroline coordination compound involving biologically relevant π-stacking and unconventional anion-π interactions considering cytotoxicity in Dalton's Lymphoma (DL) malignant cancer cells. • Phenanthroline based coordination compounds of Ni(II) and Cu(II). • Unconventional enclathration of a single guest water molecule and Benzoates. • MEP surface analysis and DFT calculations. • Anti-parallel π-stacking and Unconventional anion–π interactions. • MTT cell viability and apoptosis assays in Dalton's Lymphoma cancer cell lines. Two new coordination compounds of Ni(II) and Cu(II), viz. [Ni(phen) 2 Cl(H 2 O)] 4-NO 2 bz·3H 2 O (1) and [Cu(phen) 2 Cl]Cl·5H 2 O (2) (phen = 1,10-phenanthroline, 4-NO 2 bz = 4-nitrobenzoate) have been synthesized and characterized by single crystal X-ray diffraction, elemental analysis, FT-IR, electronic spectroscopy, TGA and EPR. The detailed crystal structure analysis of the Werner Type Clathrate 1 reveals the self-assembled unconventional enclathration of 4-NO 2 bz moieties in supramolecular Ni(II) hosts. In addition to the conventional discrete (H 2 O) n clusters in the crystal structure of 2 , the layered architecture involves enclathration of single guest water molecules in the Cu(II) supramolecular hosts. We have theoretically analysed the biologically relevant anti-parallel π-stacking interactions in compound 1 and two types of anion–π interactions involving coordinated and uncoordinated chloride ions in compound 2. MEP surface analysis and DFT calculations reveal that the anti-parallel π-stacking interaction in 1 is energetically significant and enhanced upon complexation of the ligands to the Ni(II) centre. Remarkably, studies also reveal that in addition to the conventional anion⋯π interaction involving the chloride anion in the lattice, the unusual Cl(chlorido)⋯π interaction observed in the crystal assembly of 2 is also energetically significant. The antiproliferative potential of the compounds 1 and 2 have been studied in Dalton's Lymphoma (DL) malignant cancer cell lines considering MTT cell viability and apoptosis assays. The compounds 1 and 2 exhibited significant concentration dependent increase in cell cytotoxicity and apoptosis in DL cells with negligible cytotoxicity in normal (PBMC) cells. [ABSTRACT FROM AUTHOR]

• Pyridine based Coordination compounds ofNi(II) and Zn(II). • MEP surface and QTAIM analyses on supramolecular assemblies. • Unconventional anion⋯π and C–H⋯π(nitrile) contacts. • Energetically significant unconventional anti-parallel CN⋯CN interaction. • In vitro anticancer activities in Dalton's lymphoma (DL) cell line. • Pharmacophore features based on Structure Activity Relationship (SAR). Two new coordination compounds viz. [Ni(2,6-PDC)(Hdmpz)(H 2 O) 2 ∙H 2 O (1) and [Zn(3-CNpy) 2 Cl 2 (2) (2,6-PDC = 2,6-pyridinedicarboxylate, Hdmpz = 3,5-dimethylpyrazole, 3-CNpy = 3-cyanopyridine) have been synthesized and characterized using elemental analysis, thermogravimetric analysis, electronic, infrared spectroscopy and single crystal X-ray diffraction techniques. Crystal structure analyses reveal the presence of supramolecular assemblies involving interesting dimers with unconventional contacts in the compounds. DFT (Density Functional Theory) calculations on the supramolecular dimers in the crystal structure of 1 reveal that the sum of contributions of anion–π, π–π and other long range interactions due to the approximation of the bulk monomers is energetically significant. Molecular Electrostatic Potential (MEP) surface and Quantum Theory of Atoms in Molecules (QTAIM) analyses on the interesting supramolecular dimers of the crystal structures of 2 reveal the presence of unconventional anion⋯π contacts involving coordinated chlorido ligands and C–H⋯π(nitrile) interactions involving the π-system of the nitrile moiety of 3-cyanopyridine. Remarkably, Atoms in Molecules analysis also confirms the existence of energetically significant unconventional anti-parallel nitrile⋯nitrile interaction in the crystal structure of 2. Cell cytotoxicity of the compounds performed in Dalton's lymphoma (DL) malignant cancer cell line showed effective potency with negligible cytotoxicity in normal cells (~12%). It is interesting that compound 1 has excellent cytotoxic potency with IC 50 closer to cisplatin and can bind different biological targets with similar signalling pathways. Structure activity relationship (SAR) analyses of 1 and 2 based on pharmacophore modelling reveal that the molecular features associated with the structures of the compounds play important role in the biological activities. Energetically significant unconventional supramolecular interactions in pyridine based Ni(II) and Zn(II) complexes analyzed by MEP surface and QTAIM. Anticancer activities considering cell cytotoxicity and apoptosis in DL cancer cell lines; molecular docking and pharmacophore features have been investigated to establish structure activity relationship of the compounds. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Electrostatically enhanced π-π interactions have been analyzed by DFT calculations, molecular electrostatic potential (MEP) surface and non-covalent interaction (NCI plot) index computational tools. The cytostatic potential in Dalton's lymphoma (DL) cell line by MTT assay, apoptosis assay have been further corroborated with molecular docking simulation. Three new isostructural coordination solids viz. [Co(3-CNpy) 2 (2-ClBz) 2 (H 2 O) 2 (1), [Mn(3-CNpy) 2 (2-ClBz) 2 (H 2 O) 2 (2) and [Zn(3-CNpy) 2 (2-ClBz) 2 (H 2 O) 2 (3) (3-CNpy = 3-cyanopyridine, 2-ClBz = 2-chlorobenzoate) have been synthesized from purely aqueous media and characterized by X-ray crystal structure analysis, FT-IR, electronic spectra and TGA. Several non-covalent hydrogen bonding interactions of the types O H⋯O, C H⋯O, C H⋯N, C H⋯Cl and π-π stacking contacts build up the supramolecular networks in the crystal structures. Electrostatically enhanced π-π interactions are observed in 1 – 3 between the phenyl rings of 2-ClBz and pyridine ring of 3-CNpy of the monomeric units of the complexes. We have used the molecular DFT calculations to evaluate energetically the strength of these contacts and also to analyze the effect of the metal on the interaction energies. The energetic features of the H-bonding and π-stacking interactions for 1 – 3 reveal that the H-bonded assembly is more favorable than the π-stacked contacts. The electrostatically enhanced energy of the π-stacking interactions is stronger than that usually observed for π-stacking interactions involving arenes. The cytostatic potential of all complexes have been studied in Dalton's lymphoma (DL) cell line by MTT assay, apoptosis assay and further corroborated with molecular docking simulation. The complexes exhibit cytotoxicity (∼25–30%) through apoptotic cell death with negligible cytotoxicity (∼5–10%) in normal PBMC cells. In silico-docking techniques have been performed with apoptosis regulator protein BCL-2 for the identification of critical amino acids and their possible binding affinity with the synthesized complexes. The pharmacophore features based on structure activity relationship (SAR) of the complexes have been identified and the study reveal that the features viz., hydrophobic, aromatic, positive ionizable, negative ionizable, H-bond donor and acceptor and halogen bond donor properties play important role for the biological activities of the complexes. [ABSTRACT FROM AUTHOR]

Unconventional antiparallel CO⋯CO contacts in the solid state structures of two new complexes have been analyzed by DFT calculations, molecular electrostatic potential (MEP) surface and non-covalent interaction (NCI plot) index computational tools. Both the compounds interact with anti-apoptotic cancer target proteins and the results are comparable with respective reference inhibitors. • Supramolecular association in Co(II) and Mn(II) complexes involving 2,5-pyridinedicarboxylate. • Antiparallel unconventional CO⋯CO interactions have been analyzed by DFT calculations. • The anticancer activity has been studied in Dalton's lymphoma (DL) cell line. • MTT based cytotoxicity, fluorescence based apoptosis, molecular docking and pharmacophore modelling. • Significant pharmacophore features for anticancer activities. Two new coordination solids viz. [Co(2,5-PDC)(H 2 O) 4 2H 2 O (1) and [Mn(2,5-PDC)(H 2 O) 4 2H 2 O [2,5-PDC = 2,5-pyridinedicarboxylat] (2) have been synthesized and characterized by Single crystal X-ray analysis, FT-IR, electronic spectra and TGA. Single-crystal X-ray diffraction studies reveal that compounds 1 and 2 are isostructural and extensive O H⋯O hydrogen bonds along with C H⋯O and anion⋯π interactions stabilize the crystal structures. The lattice water molecules are responsible for the 3D framework of the complexes. The remarkable combination of O H⋯O, anion–π and antiparallel CO⋯CO interactions observed in the solid state structures have been analyzed by means of DFT calculations, molecular electrostatic potential (MEP) surface and non-covalent interaction (NCI plot) index computational tools. The anticancer activity of synthesized complexes has been studied in Dalton's lymphoma (DL) cell line using MTT based cytotoxicity study, fluorescence based apoptosis study, molecular docking and pharmacophore modeling. Both complexes significantly (P ≤ 0.05) induced cytotoxicity through apoptotic cell death in DL cells with negligible cytotoxicity (∼5–10%) in normal blood cells. It is worth mentioning that compounds 1 and 2 interact with highly expressed anti-apoptotic cancer target proteins under study with higher binding affinity and the results are comparable with respective reference inhibitors. Moreover, both complexes also bear significant pharmacophore features such as H-bond donor and acceptor, aromatic and hydrophobic sites which are responsible for anticancer activities. [ABSTRACT FROM AUTHOR]