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Novel bioactive 5-chloro isatin based Schiff base ligands, (N,N'E,N,N'Z)-N,N'-(5-chloroindoline-2,3-diylidene)bis(5-nitrobenzo [d]thiazol-2-amine), L(1) and (N,N'E,N,N'Z)-N,N'-(5-chloroindoline-2,3-diylidene)bis(5-nitrothiazol-2-amine), L(2) derived from 2-amino 5-nitrobenzothiazole and 2-amino 5-nitrothiazole and their metal complexes, [Cu(L(1))2]Cl2;1, [Zn(L(1))2(H2O)2]Cl2;2, [Cu(L(2))2]Cl2;3 and [Zn(L(2))2(H2O)2]Cl2;4 have been synthesized. The composition, stoichiometry and geometry of the proposed ligands and their complexes have been envisaged by the results of elemental analyses and spectroscopic data (FT-IR, (1)H NMR and (13)C NMR, Mass and EPR). The molar conductivity values of the metal complexes revealed their ionic nature. The thermal stability of metal complexes was demonstrated by TGA/DTA studies while the crystalline nature of the complexes has been ascertained by XRD. Furthermore, a comparative account of in vitro antibacterial study against different bacterial strains with respect to standard antibiotic and scavenging activity against standard control at different concenterations unfolded pronounced antibacterial and radical scavenging potencies of the metal complexes as compared to free ligands. In addition, in vitro cytotoxicity of ligands and its metal complexes was also screened on MCF7 (Human breast adenocarcinoma), HeLa (Human cervical carcinoma) and HepG2 (Human Hepatocellular carcinoma), cell lines and normal cells (PBMC). The antiproliferative outcomes revealed that metal complexes exhibit superior activity in general as compared to free ligands (L(1) and L(2)) where metal complexes (1 and 2) of 5-chloro isatin linked benzothiazole motif (L(1)) are found to have better prospect of acting as chemotherapeutic agents which can be explained in terms of greater biopotency, planarity and conjugation against all the tested cancer cell lines with IC50<2.80 μM., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The mononuclear Schiff base complexes of the type, [ML(CH(3)OH)(2)] [M = Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by template condensation of L-leucine and glyoxal. The complexes have been characterized on the basis of the results of the elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz, FT-IR, Mass, (1)H NMR and (13)C NMR spectra. The UV-vis and magnetic moment data revealed an octahedral geometry around Co(II), Ni(II) ion with distortion around Cu(II) ion complex confirmed by EPR data. The conductivity data show a non-electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that all the complexes exhibit a significant binding to calf thymus DNA., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The Schiff base ligand, N,N'-bis-(2-thiophenecarboxaldimine)-3,3'-diaminobenzidine (L) obtained from condensation of 2-thiophenecarboxaldehyde and 3,3'-diaminobenzidine, was used to synthesize the complexes of type, [M2L2]Cl4 [M=Co(II), Ni(II), Cu(II), Cd(II) and Hg(II)]. The newly synthesized ligand (L) was characterized on the basis of the results of elemental analysis, FT-IR, 1H NMR, 13C NMR, mass spectroscopic studies and single crystal X-ray crystallography. The characteristic resonance signals in 1H NMR and 13C NMR spectra indicated the presence of azomethine group as a result of condensation reaction. The stoichiometry, bonding and stereochemistries of complexes were ascertained on the basis of results of elemental analysis, magnetic susceptibility measurements, molar conductance and spectroscopic studies viz., FT-IR, 1H and 13C NMR, UV-vis and EPR. EPR, UV-vis and magnetic moment data revealed an octahedral geometry for complexes with distortion in Cu(II) complex and conductivity data show 1:2 electrolytic nature of complexes. Absoption and fluorescence spectroscopic studies supported that Schiff base ligand L and its Co(II), Ni(II) and Cu(II) complexes exhibited significant binding to calf thymus DNA. The complexes exhibited higher affinity to calf thymus DNA than the free Schiff base ligand L., (Copyright © 2011 Elsevier B.V. All rights reserved.)

A new Cu(II) complex, [CuL1L2(CH3COO)2(H2O)]·H2O, was synthesized by the reaction of Cu(CH3COO)2·H2O, 6-phenylpyridine-2-carboxylic acid (HL1), and 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine (L2) in ethanol-water (v:v = 1:1) solution. The Cu(II) complex was characterized using elemental analysis, IR, UV-vis, TG–DTA, and single-crystal X-ray analysis. The fluorescence properties of the copper complex were also evaluated. The structural analysis results show that the Cu(II) complex crystallizes in the triclinic system with space group P-1. The Cu(II) ion in the complex is five-coordinated with one O atom (O2) and one N atom (N1) from one 6-phenylpyridine-2-carboxylate ligand (L1), one N atom (N2) from 4-[5-(pyridin-4-yl)-1,3,4-oxadiazol-2-yl]pyridine ligand (L2), one O atom (O4) from acetate, and one O atom (O5) from a coordinated water molecule, and it adopts a distorted trigonal bipyramidal geometry. Cu(II) complex molecules form a two-dimensional layer structure through intramolecular and intermolecular O-H...O hydrogen bonding. The two-dimensional layer structures further form a three-dimensional network structure by π-π stacking interactions of aromatic rings. The analysis of the Hirschfeld surface of the Cu(II) complex shows that the H...H contacts made the most significant contribution (46.6%) to the Hirschfeld surface, followed by O...H/H...O, N...H/H...N and C...H/H...C contacts with contributions of 14.2%, 13.8%, and 10.2%, respectively. In addition, the photocatalytic CO2 reduction using Cu(II) complex as a catalyst is investigated under UV-vis light irradiation. The findings reveal that the main product is CO, with a yield of 10.34 μmol/g and a selectivity of 89.4% after three hours. [ABSTRACT FROM AUTHOR]

The azo ligand obtained from the diazotization reaction of 2-aminobenzothiazole and 4-nitroaniline yielded a novel series of complexes with Co(II), Ni(II), Cu(II), and Zn(II) ions. The complexes were investigated using spectral techniques such as UV-Vis, FT-IR, 1H and 13C NMR spectroscopic analyses, LC-MS and atomic absorption spectrometry, electrical conductivity, and magnetic susceptibility. The molar ratio of the synthesized compounds was determined using the ligand exchange ratio, which revealed the metal-ligand ratios in the isolated complexes were 1:2. The synthesized complexes were tested for antimicrobial activity against S. aureus, E. coli, C. albicans, and C. tropicalis bacterial species. Additionally, their binding affinities were predicted using molecular docking analysis, and their pharmacokinetic and drug-likeness properties were evaluated. [ABSTRACT FROM AUTHOR]

S-4-methylbenzyl-β-N-(2-methoxybenzylmethylene)dithiocarbazate ligand, 1, prepared from S-(4-methylbenzyl)dithiocarbazate, was used to produce a novel series of transition metal complexes of the type, [M (L)2] [M = Cu(II) (2), Ni(II) (3), and Zn(II) (4), L = 1]. The ligand and its complexes were investigated by elemental analysis, FTIR, 1H and 13C-NMR, MS spectrometry, and molar conductivity. In addition, single X-ray crystallography was also performed for ligand, 1, and complex 3. The Hirshfeld surface analyses were also performed to know about various bonding interactions in the ligand, 1, and complex 3. The investigated compounds were also tested to evaluate their cytotoxic behaviour. However, complex 2 showed promising results against MCF-7 and MDA-MB-213 cancer cell lines. Furthermore, the interaction of CT-DNA with ligand, 1, and complex 2 was also studied using the electronic absorption method, revealing that the compounds have potential DNA-binding ability via hydrogen bonding and hydrophobic and van der Waals interactions. A molecular docking study of complex 2 was also carried out, which revealed that free binding free energy value was −7.39 kcal mol−1. [ABSTRACT FROM AUTHOR]

A novel series of mononuclear complexes of the type, [M(L)(H2O)2] [M = Co(II) (1), Ni(II) (2), Zn(II) (3), Cd(II) (4), L = dipicolinate), has been investigated using various techniques, including elemental analyses, FT-IR, ¹H- and 13C NMR spectroscopy, powder XRD and thermogravimetric analysis. The results indicate that the coordination of the dipicolinic acid to the metal ions involves two carboxylate O atoms, the pyridine N atom, and two water molecules. The pyridine-2,6-dicarboxylic acid and its studied compounds have been screened against microbial species. The findings show that the complexes have higher activity in comparison to the free pyridine-dicarboxylic acid. [ABSTRACT FROM AUTHOR]

Novel ligand, (E)-4-((4-(dimethylamino)benzylidene)amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one, L and its nickel, copper, and zinc complexes were designed and physicochemically investigated using various spectroscopic studies. Ligand was additionally characterized by single-crystal X-ray crystallography. DFT and Hirschfeld surface analysis studies were also carried out. The well-characterized compounds were tested for their antimicrobial activities. [Display omitted] A novel series of metal complexes of 3d elements of the type, [MLCl 2 ] [M = Ni(II), Cu(II) & Zn(II), L = ligand] produced from an ampyrone-based ligand was discussed. A thorough investigation was carried out using elemental analyses, LC-MS, FT-IR, 1H- &13C NMR, and thermogravimetric analysis for the ligand and its complexes. The ligand was additionally characterized through single crystal X-ray crystallography, revealing a monoclinic system with the C 2/ c space group, featuring dimensions a = 17.8776(12) Å, b = 6.8982(6) Å, c = 29.862(2) Å, β = 101.170(5)°. Hirshfeld surface analysis was employed to unveil various intermolecular interactions in the ligand. Additionally, theoretical investigations were conducted to have a better understanding of the structures. Moreover, the antimicrobial efficacy of all investigated compounds was assessed. [ABSTRACT FROM AUTHOR]

In this work, six new mixed ligand Schiff base metal complexes of [M2(L1)(X)2Cl4] type, (where, M = CoII, NiII, CuII, L1 = Schiff base ligand derived from 1‐pyrenecarboxaldehyde and 1,4‐bis[3‐aminopropyl]piperazine and X = pyrazine‐2‐carboxylic acid or 2,2′‐biimidazole) were synthesized and studied their biological activity and cytotoxicity. The synthesized Schiff base ligands, their metal complexes were characterized by Infrared, UV‐Visible spectroscopy, and elemental analysis. Density functional theory calculations were performed to examine the molecular geometry and frontier molecular orbital properties of complexes (1–6). The DNA binding ability of these complexes (1–6) was evaluated by in vitro spectroscopic (absorption and fluorescence) titrations, viscosity measurements, and in silica by molecular docking measurements. The results showed a good binding propensity with the binding constant from 2.65 × 104 to 3.38 × 105 M−1 in the order 6 > 5 > 4 > 3 > 2 > 1, respectively. All complexes exhibited a good binding affinity to BSA proteins with relatively higher binding constant values similar to the trend of DNA binding studies and where Cu (II) complexes have greater efficiency than Co (II) and Ni (II) complexes. The in vitro cytotoxic study of all the complexes was investigated in the cervical cancer (HeLa) cell line, which displayed IC50 values of 1.36–24.2 μM, signifying the potential of complexes for an operative anticancer drug. Metal complexes were also screened for antimicrobial properties, which showed virtuous inhibition than the free ligands. [ABSTRACT FROM AUTHOR]

A new series of spirooxindole analogs tethered pyrazole scaffold constructed via [3+2] cycloaddition (32CA) reaction starting from the new chalcone named (E)‐3‐(5‐chloro‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)‐1‐(5‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)prop‐2‐en‐1‐one which confirmed by single crystal X‐ray diffraction analysis. Synthesized spirooxindole analogs were evaluated for their neuroprotection through the inhibition of acetylcholine esterase enzyme using Ellman's method. Compounds 9 w, 9 e and 9 x showed the strongest acetylcholine esterase inhibition (AChEI) with IC50 values of 5.7, 7.8 and 8.3 μM, respectively. Obviously, the incorporation of NO2 group into isatin 5th position and N‐methylglycine (sarcosine) play a crucial role for the activity which lead to compound 9 w had the most potent inhibitory activity with IC50 value of 5.7 μM. Molecular docking was used to study their interaction with the active site of hAChE. These 32CA reactions takes place via a one‐step mechanism with a high polar character as a consequence of the supernucleophilic character of azomethine yildes and the strong electrophilic character of ethylenes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Zinc complex with a N4-donor Schiff base. • Crystal structure. • DFT study. • Pharmacological properties. Abstract A tetradentate Schiff base ligand, L (L = N , N ′-bis(1-(2-pyridyl)ethylidene)-2,2-dimethylpropane-1,3-diamine) was used in the preparation of a new mononuclear Zn(II) complex, [Zn(L)Cl]. The complex was structurally investigated by elemental analyses, spectroscopic studies and single crystal X-ray crystallography. Furthermore, to obtain insights into the structure, the ground state geometry of zinc complex cation was examined by dispersion corrected DFT method i.e. B3LYP-D3 within unrestricted scheme. Intermolecular contacts in the crystal structure were calculated and quantified by examination of Hirshfeld surface and fingerprint plots. In addition, the pharmacological properties of the newly synthesized complex were examined to explore the in vitro antibiofilm activity against P. aeruginosa , and anticancer activity against Human breast adenocarcinoma (MCF-7) cell line. Furthermore, molecular docking study was also recorded to find out various modes of virtual interactions between the zinc complex cation and the active site of receptor (PDB: 1gzt). [ABSTRACT FROM AUTHOR]

Molecular mechanism suggests that the incorporation of an antioxidant organic moiety to chromium will be a sound strategy for the synthesis of safer and more effective hypoglycemic compounds. Two Schiff base ligands were derived by condensation of isonicotinyl hydrazide with salicylaldehyde/o-hydroxyacetophenone which further yield four novel chromium(III) complexes of types [Cr(L)Cl2(H2O)] and [Cr(L)2]Cl. The ligands and complexes were characterized by analytical and spectroscopic techniques. DFT study at the basic set B3LYP and TD-SCF/6-311-G level was employed to confirm the geometry of the investigated compounds. Ligands were tested for their antioxidant activity and exhibited good antioxidant activity. Assessment of insulin-like activity of the complexes was initially performed in vitro by measuring the inhibition of α-amylase. The complex with highest in vitro activity was investigated for in vivo antidiabetic activity on the model of STZ-induced diabetic rats, which demonstrated that complex 4 significantly lowers the blood glucose level in rats. Toxicity level and antioxidant activity of the complex were also tested, which exhibit good tolerance level and antioxidant activity. Histological analysis of the pancreas of animals under investigation reveals the good condition of the pancreas treated with the complex. Ligands and complexes were also tested for antibacterial activity against Escherichia coli. [ABSTRACT FROM AUTHOR]

A Novel Cu(II) complex, [(Cu) 3 (Saly) 3 ], was synthesized and analyzed using elemental analysis, UV–Vis, FT-IR spectroscopy, and single crystal X-ray crystallography. The crystal adopts an orthorhombic structure. Additional insights into the structure were obtained through DFT and Hirscfel surface analyses. The complex exhibits potent antimicrobial activity. Molecular docking simulations on protein structures were identified by PDB IDs: 1DTD, 3FVU, and 4UXU, with the aim of evaluating the binding affinity of the investigated compound. [Display omitted] A novel Cu(II) complex, designated as [(Cu) 3 (Saly) 3 ], has been synthesized and studied using a variety of physiochemical methods, including elemental analysis, UV–Vis, and FT-IR spectroscopy. In order to further investigate the structure of the complex, single crystal X-ray crystallography has also been used, which reveals that the crystal exits in an orthorhombic system with the structural parameters a = 5.2212(4) Å, b = 10.5554(10) Å, c = 21.859(2) Å and Z = 4. The antimicrobial activity of the studied complex is carried out, suggesting it to be strong antimicrobial agent. For in silico studies, molecular docking simulations were performed on the crystal structure of target protein (PDB ID) 1DTD, 3FVU, and 4UXU in order to assess the ability of the investigated complex to attach to these target macromolecules. [ABSTRACT FROM AUTHOR]

The use of the monoanionic Schiff base ligand (E)-4-(2-hydroxybenzylideneamino)-2,3-dimethyl-1-phenyl-1,2-dihydropyrazol-5-one in transition (Co, Ni and Cu) coordination chemistry yields mono-, tetra- and pentanuclear coordination clusters (CCs) with different structural motifs. An organic transformation occurs in the ligand in the Cu compound for which theoretical studies are presented. Solution studies, topological issues and magnetic studies are discussed. The present results demonstrate the richness of the coordination chemistry of this monoprotic organic ligand, which promotes the formation of high-nuclearity CCs. [ABSTRACT FROM AUTHOR]

• Characterization by single-crystal X-ray crystallography and spectroscopic studies. • Chemical activity and MEP were investigated by the DFT method. • Crystal packing was determined with Hirshfeld surface. • Molecular docking was performed to explore the binding modes of the compound. A novel nitrothiophene derivative, ((Z)- N -(4-nitrophenyl)-1-(5-nitrothiophen-2-yl)ethan-1-imine, NNPEI, was synthesized by a condensation reaction and characterized by FT-IR, UV–Vis., 1H-NMR and 13C-NMR spectroscopy, and single-crystal X-ray crystallography. The structure was further confirmed by theoretical studies using the DFT/B3LYP method with LanL2Z basis set. The experimental results agree well with the findings of theoretical studies. The chemical reactivity and kinetic stability of molecular compounds are determined using the molecular frontier orbitals, HOMO and LUMO. Hirshfeld surface analysis was used to measure different interactions, revealing that the main contributions to the crystal packing come from the interactions O···H/H···O (42%), C···H/H···C (9.5%), H···H (8.9%), S···H/H···S (7.9%) and N···H/H···N (6.3%). Furthermore, molecular docking was used to investigate the binding interactions between MCL1 and NNPEI to choose possible conformation. [ABSTRACT FROM AUTHOR]

Abstract: A novel Ru(II)-Schiff base complex has been synthesized by the interaction of ligand, 1,3-bis{[(E)-(2-chlorophenyl)methylidene]amino}-2-propanol, L with [RuCl2(PPh3)3]. The structure of ligand, L has been determined on the basis of X-ray diffraction while the geometry of the Ru(II) complex has been ascertained by FT-IR, 1H, 13 C{1H}, 31P{1H} NMR and UV–vis studies. The in vitro antitumor activity of these compounds was assessed by examining their ability to inhibit cell proliferation against human breast and pancreatic cancer cell lines. The results show a dose-dependent anti-proliferative effect and induction of apoptotic cell death in both the cancer cell lines, thus indicating pharmacological significance of Ru(II) complex against cancer. [Copyright &y& Elsevier]

A series of functional pendant armed 14-membered Schiff-base macrocyclic complexes [ML(NO3)2], where M = Co(II), Ni(II), Cu(II), and Zn(II), has been synthesized by template condensation of 3,3′-diaminobenzidene and acetylacetone. The complexes have been characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, and electrospray ionization (ESI) mass, 1H-nuclear magnetic resonance (NMR), infrared (IR), electronic, and electron paramagnetic resonance (EPR) spectral studies. The results of elemental analyses, ESI mass spectroscopy, and conductivity measurements confirmed the stoichiometry of the complexes, while the characteristic absorption bands and resonance peaks in IR and NMR spectra confirmed the formation of frameworks of complexes. The molar conductance measurements of the complexes in dimethyl sulfoxide (DMSO) correspond to being non-electrolyte in nature. However, the overall geometry of the complexes has been assigned on the positions of bands in electronic spectra and magnetic moment data. The distortion in Cu(II) complexes has been deduced on the basis of EPR data. Absorption and fluorescence studies on the Cu(II) complex show a significant binding to CT DNA. [ABSTRACT FROM AUTHOR]

Abstract: A novel tetradentate Cu(II) complex of the type, [CuL](NO3)2 was synthesized by the interaction of Schiff base ligand, N,N-bis[(E)-2-thienylmethylidene]-1,8-naphthalenediamine, L obtained by the condensation of thiophene-2-carboxaldehyde and 1,8-diaminonaphthalene. The formation of Schiff base ligand, L and its Cu(II) complex was confirmed on the basis of results of elemental analyses, mass, FT-IR, 1H and 13C{1H} NMR spectral studies. UV–Vis, EPR and magnetic susceptibility data support a square planar environment around Cu(II) ion. However, molar conductance values confirmed 1:2 electrolytic nature for the Cu(II) complex. The electrochemical studies of Cu(II) complex was carried out by using cyclic voltammetry which revealed the complex to exhibit quasi reversible process. The biological activity of Cu(II) complex such as ability to bind DNA and DNA cleavage were studied where the Cu(II) complex was shown to cause considerable DNA cleavage and also generated reactive oxygen species such as superoxide anion. Since it is known that various anticancer drugs act through induction of oxidative stress that is mediated by reactive oxygen species, our results suggest a putative role of Cu(II) complex similar to various anticancer drugs. [Copyright &y& Elsevier]

A 16-membered tetraazamacrocyclic ligand has been synthesized by condensation reaction of 2-methyl acetoacetanilide with 1,8-diaminonaphthalene, and the metal complexes of the type [MLCl2] [M = Co(II), Ni(II), Cu(II), Zn(II)] were prepared by interaction of the ligand with metal salts. The ligand and its complexes were characterized by various spectroscopic studies. The mode of bonding and the overall geometry of these complexes have been deduced by elemental analysis, molar conductance values, Fourier-transform infrared (FT-IR), 1H-nuclear magnetic resonance (NMR), fast-atom bombardment (FAB) mass, electron paramagnetic resonance (EPR), and ultraviolet–visible (UV-VIS) spectroscopy along with magnetic measurement studies. An octahedral geometry has been envisaged for all these complexes, while a distorted octahedral geometry has been noticed for the Cu(II) complex. The cyclic voltammograme of the Cu(II) complex exhibits a quasi-reversible one-electron transfer wave for the Cu(II)/Cu(I) couple. The low conductivity data of all the complexes suggest their nonionic nature. These complexes have also been screened against pathogenic bacteria and fungi in vitro as growth-inhibiting agents. [ABSTRACT FROM AUTHOR]

Two Schiff bases, L1 (5,6;11,12-dibenzophenone-2,3,8,9-tetramethyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene) and L2 (6,7;13,14-dibenzophenone-2,4,9,11-tetramethyl-1,5,8,12-tetraazacyclotetradeca-1,4,8,11-tetraene), bearing functionalized pendant arms have been synthesized by cyclocondensation of 3,4-diaminobenzophenone with 2,3-butanedione and 2,4-pentanedione, respectively. Mononuclear macrocyclic complexes [FeL1Cl2]Cl, [FeL2Cl2]Cl, [ML1Cl2], and [ML2Cl2] (where M = Co(II) and Cu(II)) have been prepared by reacting iron(III), cobalt(II), and copper(II) with the preformed Schiff base. The ligands and their corresponding metal complexes were characterized by elemental analyses, ESI-mass spectra, conductivity, magnetic moments, UV-Vis, EPR, IR, 1H-, and 13C-NMR spectral studies, and TGA-DTA/DSC data. The TGA profiles exhibit a two-step pyrolysis, although the iron complexes decompose in three steps, leaving behind metal oxides as the final product. The ligands and complexes were screened in vitro against Gram-positive bacteria, Gram-negative bacteria, and fungi. [ABSTRACT FROM AUTHOR]

Abstract: The Schiff base ligand, N,N’-bis-(2-pyridinecarboxaldimine)-1,8-diaminonaphthalene (L), obtained by the condensation of 2-pyridinecarboxaldehyde and 1,8-diaminonaphthalene, has been used to synthesize the mononuclear complexes of the type [MLCl2] [M=Co(II), Ni(II), Cu(II) and Zn(II)]. The newly synthesized ligand (L) and its complexes have been characterized on the basis of results of elemental analysis, molar conductance, magnetic susceptibility measurements, Job''s method and spectroscopic studies viz., FT-IR, Mass, 1H and 13C NMR. The UV–vis and magnetic moment data revealed an octahedral geometry around Co(II), Ni(II) and Cu(II) ions and conductivity data show a non-electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that Cu(II) complex exhibits significant binding to calf thymus DNA. [Copyright &y& Elsevier]

Abstract: The Schiff base ligand, 1,2-diaminophenyl-N,N′-bis-(2-pyridinecarboxaldimine), (L) has been synthesized by the reaction of o-phenylenediamine and 2-pyridinecarboxaldehyde, and a series of mononuclear complexes of the type [ML(NO3)2] [M=Co(II), Ni(II), Cu(II) and Zn(II)] has also been synthesized. The formation of the Schiff base ligand (L) and its complexes have been envisaged from IR, 1H and 13C NMR studies. The absorption band observed in the electronic spectra and magnetic moment values confirm an octahedral environment around the metal ion. The molar conductivity measurements confirm the non-ionic character of these complexes. Fluorescence and UV–Vis absorption studies performed on the Cu(II) complex revealed a significant binding ability to DNA. [Copyright &y& Elsevier]

A novel zinc complex was prepared by the reaction of one equivalent of a bidentate Schiff base, N,N′-bis(2-chlorobenzylidene)-2,2-dimethylpropane-1,3-diamine, L with one equivalent of zinc chloride in methanol, and characterized by elemental analyses, NMR, IR and single crystal X-ray crystallography. The crystallographic studies revealed that the zinc ion in the complex is coordinated to two imine nitrogen atoms of L and two chloride ions of zinc chloride. Furthermore, to obtain insights into the structure and bonding, density functional theory (DFT) calculations were performed. The obtained results were found to be similar with the results obtained from the experimental findings. In addition, the anti-inflammatory activity of the studied zinc complex was also evaluated. The results obtained showed the studied complex could be a good candidate in treatment of inflammatory disorders. • Synthesis of a zinc complex from N,N′-bis(2-chlorobenzylidene)-2,2-dimethylpropane-1,3-diamine ligand. • Characterization by spectroscopic studies and single crystal X-ray crystallography. • Zinc ion is coordinated to two imine nitrogen atoms of the ligand and two chloride ions to assume tetrahedral geometry. • DFT studies in order to confirm the experimental findings. • The complex exhibited good activity in the treatment of inflammatory disorders. [ABSTRACT FROM AUTHOR]

We are reporting a novel azo-azomethine ligand, HL and its complexes with Cu(II) and Fe(III) ions. The ligand and its complexes are characterized by various physico-chemical techniques using C,H,N analyses, FT-IR, 1H-NMR, ESI-MS and UV-Vis studies. TGA analyses reveal complexes are sufficiently stable and undergo two-step degradation processes. The redox behavior of the complexes was evaluated by cyclic voltammetry. Furthermore, the ligand and its complexes were tested for antimicrobial activity against bacterial and fungal strains by determining inhibition zone, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). The complexes showed moderate antimicrobial activity when tested against Gram +ve and Gram −ve bacterial strains. To obtain insights into the structure of ligand, DFT studies are recorded. The results obtained are quite close to the experimental results. In addition, the energy gap, chemical hardness, softness, electronegativity, electrophilic index and chemical potential were calculated using HOMO, LUMO energy value of ligand. [ABSTRACT FROM AUTHOR]

Abstract A novel series of complexes of the type, [ML 2 ].nH 2 O, [where L = 2-(α-methyl salicylidene–2′-imino) aminobenzo thiazole (HMAB), 2-(α-phenyl salicylidene–2′-imino) aminobenzo thiazole (HPAB), 2-(o-Vanillidene–2′-imino) amino benzothiazole (HVAB)] have been reported. These Schiff bases and their transition metal complexes were fully characterized by several physico-chemical and spectral techniques, which revealed the tridentate chelation of ligand. The DFT calculations of these reported compounds were made to obtain bonding inside the structure by GAUSSIAN 03 programme platforms. The QSAR study was performed by HyperChem Professional 8.0.3 software to explain the biological effeteness of the ligands. A docking analysis using the AutoDock Vina software was carried out to understand the binding pattern of the investigated compounds towards target proteins CYP121 and CYP51 from Mycobacterium tuberculosis. Furthermore, all the compounds have been reported to exhibit significant antifungal activity when tested against Aspergillus flavus and Aspergillus niger. Graphical abstract Image Highlights • Schiff base ligands are prepared from 2-hydrazinobenzothiazole. • The metal complexes are synthesized and characterised by spectroscopic, thermal and X.R.D. powder pattern. • Molecular modelling of the ligands and their Cu & Zn complexes are made to understand the mode of bonding. • Molecular docking, QSAR and antifungal study were ascertained to verify the bio-potency of the compounds. [ABSTRACT FROM AUTHOR]

Abstract: The template condensation reaction between glyoxal and 1,8-diaminonaphthalene resulted a few novel mononuclear 14-membered tetraimine macrocyclic complexes of the type, [MLX2] [M=Co(II), Ni(II), Cu(II) and Zn(II), for X=Cl or NO3]. The stoichiometry and the nature of the complexes have been deduced from the results of elemental analyses and conductance data. The formation of macrocyclic framework has been inferred from the appearance of imine υ(Cx3c5;(Mn IR spectra and the resonance signals observed in 1H and 13C-NMR spectra. However, the overall geometry of the complexes has been assigned on the positions of bands in electronic spectra and magnetic moment data. The distortion in Cu(II) complexes has been deduced on EPR data. The thermal behavior of these complexes has been studied by TGA analysis. Absorption and circular dichroism studies on the complex proved a significant binding to calf thymus DNA. [Copyright &y& Elsevier]

• A series of mixed-ligand complexes was synthesized by using a Schiff base as main ligand and nicotinamide as secondary ligand. • The Schiff base was prepared by the interaction of ampicillin drug and 4-chlorobenzophenone. • The DFT calculations and molecular docking analysis were carried out. • The synthesized complexes exhibited significant antimicrobial activity. • The drug-likeness and toxicity of the compounds were also performed. A novel series of mixed-ligand complexes of the type, [ML 1 (L 2) 3 Cl x [M= Cr(III), Fe(III), Co(II),Ni(II), Cu(II), Cd(II) and Hg(II), n = 2, 3], was synthesized using Schiff base (HL 1) as main ligand, nicotinamide (L 2) as secondary ligand, and the corresponding metal ions in 1:3:1 molar ratio. The main ligand, HL 1 was prepared by the interaction of ampicillin drug and 4-chlorobenzophenone. The synthesized mixed ligand complexes were characterized by elemental analysis, UV-Vis, FT-IR,1H-NMR,13C-NMR and TG/DTG studies. In the mixed-ligand complexes, the Schiff base ligand, HL 1 showed coordination to the central metal ion in tridentate manner via azomethine nitrogen, β-lactam ring oxygen and deprotonated carboxylic oxygen atoms, whereas the secondary ligand L 2 (nicotinamide, Nam) coordinated through pyridine nitrogen atoms. The synthesized complexes exhibited significant antimicrobial activity when evaluated against P. pseudomonas, E. coli, S. aureus and B. subtilis microbes. The DFT calculations were also carried out to ascertain the bonding insights into the structure. In addition, molecular docking analysis was performed carried out to know the interactions between complexes and their probable binding sites in penicillin binding protein (PBP2). Moreover, drug-likeness and toxicity of the compounds were also performed to predict the suitability of the complexes as drugs. Image, graphical abstract [ABSTRACT FROM AUTHOR]

[Display omitted] A novel series of 3d metal (Co(II), Ni(II), Cu(II) and Zn(II)) complexes derived from a N-(2-chlorophenyl)-2-(1,3-thiazol-2-ylamino)acetamide (CTA) ligand was reported and investigated by IR, 1H{13C NMR}, elemental analyses, mass, and UV–Vis spectroscopy which revealed an octahedral geometry around studied metal ions. The ligand and its metal complexes were screened for antimicrobial, antioxidant, antihemolytic, and cytotoxic activities. All metal complexes were found to have high bio-effectiveness when compared to ligand. Furthermore, molecular docking was used with the EGFR receptor (PDB ID: 2A91) to determine the strength of interactions between metal complexes and their ligand. In addition, MTT assays and molecular docking studies were used to examine the anticancer potential on Hep G2, P53, and Hela cell lines. The docking scores of all complexes were essentially the same with slight variations, but they were higher than their ligand, suggesting that all complexes exhibited comparable pharmacological patterns against the EGFR receptor. [ABSTRACT FROM AUTHOR]

• A novel series of Schiff base (HDMPM) metal complexes were prepared and characterized. • The anticancer activity was evaluated against HepG2, A549, HCT116, and MCF-7 cancer cell lines. • The compounds were optimized by employing Gaussian16 program package with B3LYP functional incorporating dispersion with two different basis sets (LanL2DZ and 6–31G(d,p)). • The biological effectiveness of the studied compounds were assessed against SARS-CoV-2 Omicron variant (PDB ID: 7T9K) by using Autodock Vina software. A novel Schiff base (SB) ligand, abbreviated as HDMPM, resulted from the condensation of 2-amino-4-phenyl-5-methyl thiazole and 4-(diethylamino)salicyaldehyde, and its metal complexes with [Co(II), Cu(II), Ni(II), and Zn(II)] ions in high yield were formed. The physico-chemical techniques such as elemental analysis, molar conductance, IR, 1H and 13C NMR, mass spectroscopy, and electronic absorption studies were utilized to characterize the synthesized compounds. The studied compounds were examined for their possible anticancer activity against a number of human cancerous cell lines, including A549 lung carcinoma, HepG2 liver cancer, HCT116 colorectal cancer, and MCF-7 breast cancer cell lines, with doxorubicin serving as the standard. The study revealed that Zn(II) complex showed significant activity to inhibit growth of HepG2, MCF7, A549, and HCT116 cell lines by a factor of 88, 70, 75, and 70, respectively, when compared to untreated. In addition, the reported compounds were optimized by employing Gaussian16 program package with B3LYP functional incorporating dispersion with two different basis sets (LanL2DZ and 6–31G(d,p)). Moreover, Autodock Vina software was used to assess the biological effectiveness of the studied compounds against SARS-CoV-2 Omicron variant (PDB ID: 7T9K). [ABSTRACT FROM AUTHOR]

Three novel Pd(II) Schiff base complexes have been synthesized and characterized well and their catalytic activity for the Suzuki-Miyaura coupling reactions in various organic solvents and in aqueous media have been thoroughly investigated. X-ray diffraction data of complexes confirmed a distorted square-planar geometry around Pd(II) ion in all the three complexes. [Display omitted] A novel series of stable phosphine/arsine-free Schiff base Pd(II) complexes (1 – 3) was synthesized and investigated using a variety of spectroscopic techniques and single crystal X-ray crystallography. A square-planar distortion was observed in all complexes centering on the Pd(II) ion. The isolated complexes (1 – 3) were used as catalysts for the Suzuki cross-coupling reactions in water/ethanol and water medium, resulting in good to excellent yields of the products even with a little loading of the catalyst. This methodology has the potential to be extended further to develop novel antimicrobial drugs, which can be further used in the treatment of infectious diseases. [ABSTRACT FROM AUTHOR]