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In the search of novel and effective anti‐infectious agents, new hydrazone ligands (1–4) and their diorganotin (IV) complexes (5–20) were synthesized by condensing piperonylic hydrazide with salicylaldehyde derivatives, which have been further characterized by numerous physical and spectral techniques [1H, 13C, 119Sn] NMR, mass spectroscopy, UV–Vis, IR). These techniques ascertained dibasic tridentate coupling of hydrazone ligands with diorganotin (IV) through phenolic, enolic oxygens, and imine nitrogen, demonstrating pentacoordinated stereochemistry of the complexes. The thermal stability of up to 160°C of the complexes was ascertained by TGA studies whereas low conductance signified compounds have non‐electrolytic nature. Further, the antimicrobial activity was evaluated against four bacterial and two fungal strains by serial dilution assay, which demonstrated that the metal complexes (10, 11, 12) have comparable MIC values (0.0085–0.0098 μmol/ml) with ciprofloxacin and excellent biological responses in comparison of fluconazole. The phenyl complex [Ph2SnL2] (12) was found to be the most active antimicrobial agent with the lowest MIC value (0.0085 μmol/ml). The compounds were also screened for in vitro anti‐inflammatory activity by BSA denaturation assay and the phenyl complex [Ph2SnL2] (12) has been reported as most potent with 7.62 IC50 value, which is comparable with diclofenac sodium. Further, the biologically active complexes (9–12) and their hydrazone ligand [H2L2] were theoretically analyzed by computational investigations to support the in vitro results. The molecular docking analysis of compounds was performed on the active site of C. albicans (PDB ID: 5V5Z) and E. coli (PDB ID: 1HNJ) to assess the binding interactions and binding energy. The DFT and MESP (2, 9–12) revealed the most reactive areas, molecular geometry, Mulliken atomic charges, electronegativity, etc. of the compounds (2, 9–12). The ADMET profile showed the toxicity level and drug‐likeness properties, showing their potential to operate as viable antagonists. [ABSTRACT FROM AUTHOR]

New nickel (II), cobalt (II), and several copper (II) complexes have been synthesized from the hydrazone ligand (AHTDSH; H2L); which obtained from 5‐acetyl‐4‐hydroxy‐2H‐1,3‐thiazine‐2,6(3H)‐dione with salicylaldehyde hydrazone. The structures of H2L ligand and the prepared complexes were confirmed by spectroscopic and analytical techniques. The ligand behaves as bis (monobasic bidentate) and dibasic tetradentate chelating agent via azomethine nitrogen and phenolic oxygen atoms. Octahedral geometries have been assigned for the prepared complexes. The Coats–Redfern equations were used to estimate the kinetic parameters (Ea, A, H, S, and G) of the thermal decomposition stages. The molecular structural characteristics of the ligand and its metal complexes were estimated based on density functional theory (DFT) level implemented in the Gaussian 09 software at B3LYP/6‐311G(d,p) level and the theoretical data were connected with the results of the experimental work. The anticancer activity of AHTDSH ligand and its complexes was demonstrated toward HepG2 cell lines. The interaction between the chemical and the active site of the CDK2 kinase was examined using a docking study of the hydrazone ligand and its complexes. [ABSTRACT FROM AUTHOR]

Two new oxidovanadium(V) complexes, [VOL1(aha)]DMF (1) and [VOL2(mat)] (2), where L1 and L2 are the dianionic form of N'-(4-bromo-2-hydroxybenzylidene)-3-methyl-4-nitrobenzohydrazide and N'-(3,5-dibromo-2-hydroxybenzylidene)pivalohydrazide, respectively, and aha and mat are the monoanionic form of acetohydroxamic acid and maltol, respectively, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V atoms in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated.

Four new vanadium complexes containing hydrazone and benzohydroxamate ligands with the general formula [VO(L n)(bzh)]·MeOH have been prepared and characterised. The complexes are active catalysts for epoxidation of cis -cyclooctene by tert -BuOOH, and for sulfoxidation of methyl- p -tolylsulfide by tert -BuOOH or H 2 O 2. [Display omitted] Four isostructural oxovanadium(V) complexes with hydrazone ligands have been synthesised, characterised, and evaluated as epoxidation and sulfoxidation catalysts. The reactions between [VO(acac) 2 ] (acac– = acetylacetonate) and H 2 L n (n = 1–4), precursors for monoanionic tridentate hydrazone ligands, afford complexes formulated as [VO(L n)(bzh)·MeOH] (1 – 4) when bidentate benzohydroxamic acid (Hbzh) is included as a co-ligand. Single crystal X-ray structure analyses showed that complexes 1 – 3 have a distorted octahedral coordination geometry with an O 5 N coordination environment. Cyclic voltammetry showed that all complexes undergo two quasi-irreversible reduction peaks and a single irreversible oxidation peak. The bonding in 1 has been investigated by electronic structure calculations, and these data are discussed with respect to the electrochemical results. Complexes 1 – 4 were tested as catalysts for the epoxidation of cis -cyclooctene at 50 °C and sulfoxidation of methyl- p -tolylsulfide at room temperature using tert -butyl hydroperoxide (t BuOOH) and aqueous H 2 O 2 as the terminal oxidants. [ABSTRACT FROM AUTHOR]

A new oxidovanadium(V) complex, [VOL(OEt)(EtOH)] (1), and a new dioxidomolybdenum(VI) complex, [MoO2L(OH2)] (2), where L is the dianionic form of 2-bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V and Mo ions in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated. Both complexes have effective catalytic properties for the epoxidation of styrene, with conversions over 76% and selectivities over 92%. [ABSTRACT FROM AUTHOR]

A new bromido-coordinated mononuclear copper(II) complex [Cu(HL1)Br2] (1), and a new mononuclear copper(II) complex [CuL2(HL2)]ClO4·0.5H2O (2), with the hydrazone ligands 4-tert-butyl-N’-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL1) and 4-bromo-N’-(pyridin-2-ylmethylene)benzohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the Cu atom in complex 1 is in distorted square pyramidal coordination, and that in complex 2 is in octahedral coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

A visible‐light‐induced oxidative coupling of arylboronic acids has been developed for the synthesis of biaryls. The reaction that employs polydentate hydrazones as the bifunctional catalyst works smoothly under room temperature. It is compatible with a wide range of functional group. The study of UV‐Vis spectrum indicated that hydrazone and its complex with CuI show major absorptions upon visible‐light, which secures the dual role of hydrazone as both ligand and photocatalyst in this reaction. Hence, the reaction is proposed to involve stepwise transmetallations, photo‐induced oxidations, and reductive elimination. [ABSTRACT FROM AUTHOR]

A new bromido-coordinated mononuclear manganese(II) complex [MnL1Br2(OH2)] (1), and a new nitrato-coordinated mononuclear manganese(II) complex [Mn(L2)2(ONO2)(OH2)]NO3 (2), with the hydrazone ligands 4-hydroxy-N’-(pyridin-2-ylmethylene)benzohydrazide (HL1) and N’-(pyridin-2-ylmethylene)isonicotinohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. Single crystal structural analysis shows that the Mn atom in complex 1 is in octahedral coordination, and that in complex 2 is in pentagonal bipyramidal coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

New dioxidomolybdenum(VI) complexes with the formula [MoO2L(MeOH)], derived from N'-(5-chloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L1) and N'-(3,5-dichloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L2) were prepared. Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method. Both complexes were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazones L1 and L2 coordinate to the MoO2 cores through the enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

A pair of structurally similar oxidovanadium(V) complexes with the general formula [VOLL’], with the hydrazone compounds N'-(4-oxopentan-2-ylidene)nicotinohydrazide (H2L1) and 4-bromo-N'-(4-oxopentan-2-ylidene)benzohydrazide (H2L2), and the acetohydroxamic acid (HL’) as ligands, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. Single crystal X-ray analysis indicates that the V atoms in the complexes are in octahedral coordination, with the ONO donor atoms of the hydrazone ligands, and the OO donor atoms of the acetohydroxamate ligands, as well as an oxido O atom. The complexes showed good property for the catalytic epoxidation of styrene.

A new mononuclear cobalt(III) complex, [Co(HL1)2]Cl (1), derived from the reduced Schiff base 2,2'-((ethane-1,2-diylbis(azanediyl))bis(methylene))diphenol (H2L1), and a new dinuclear cobalt(III) complex, [Co2(L2)2]∙2H2O (2), derived from the reduced Schiff base 6,6’-(2-hydroxypropane-1,3-diyl)bis(azanediyl)bis(methylene)bis(2-bromo-4-chlorophenol) (H2L2), were synthesized and characterized by infrared and electronic spectroscopy, and single crystal X-ray diffraction techniques. The ligands were synthesized first, and then bound to the Co(III) centre. Compound 1 contains a mononuclear [Co(HL1)2]+ cation and a chloride anion. The cationic moiety possesses crystallographic inversion center symmetry. Compound 2 contains a dinuclear [Co2(L2)2] molecule and two water hydrate molecules. The Co atoms in the complexes are in octahedral coordination. Both complexes showed potential antimicrobial activity.

New Schiff base hydrazone ligand 2-hydroxybenzylidene-4-oxopiperidine-1-carbohydrazone (H2L) was designed and synthesized by the condensation of 4-oxo-1-carbopiperidone hydrazide with 2-hydroxy benzaldehyde. This ligand reacts with chloride salts of Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) to give complexes [Cr(L)(H2O)2Cl] (1), [Mn(HL)(H2O)2Cl] (2), [Fe(L)(H2O)2Cl] (3), [Co(HL)(H2O)2Cl] (4), [Ni(HL)(H2O)2Cl], (5), and [Cu(HL)(H2O)2Cl] (6), respectively. The ligand was characterized by elemental and spectral (viz. IR, UV–vis, 1H NMR and 13C NMR, mass) analyses and complexes were additionally characterized by molar conductance, magnetic susceptibility measurements, ESR, powder XRD, SEM and TG analyses. The analytical data suggest 1:1 (M: L) stoichiometric for all the complexes. The ligand behaves as a dibasic tridentate, coordinating through the Ophenolate, Nazomethine, Oenolate donor functionality towards the Cr(III) and Fe(III) ion while it behaves as monobasic tridentate and coordinates through Ophenolate, Nazomethine, Oketonic in other complexes. Physicochemical data suggests an octahedral geometry for all complexes. SEM analysis revealed regular, uniform morphological size of ligand but varies in its complexes. ESR studies confirmed that stronger covalency character in π- bonding than σ bonding. X-ray diffraction study confirms semi crystalline nature of ligand and its metal complexes. Thermal behavior (TG/DTA) and kinetic parameters calculated by Coats- Redfern method suggest more ordered activated state in complex formation. The ligand and its complexes were screened for antibacterial activity against gram-negative bacteria (Escherichia coli and S. typhi), gram-positive bacteria (Staphylococcus aureus and Bacillus substillus) and the fungal activity against pathogens (Candida albicans and Aspergillus niger) and obtained data show that metal complexes are more potent than the parent ligand against bacterial species.

A new vanadium(V) complex, [VOL(OMe)(MeOH)]·MeOH (1·MeOH), was prepared by the reaction of VO(acac)2 with 2-chloro-N'-(5-fluoro-2-hydroxybenzylidene)benzohydrazide (H2L) in methanol. By addition of salicylhydroxamic acid (HSHA) to the methanolic solution of 1, a new salicylhydroxamate-coordinated vanadium(V) complex, [VOL(SHA)]·H2O (2·H2O), was obtained. Both complexes were characterized by elemental analysis, infrared spectroscopy, thermal analysis and single crystal X-ray diffraction. Complex 1 crystallizes with methanol molecule as a solvate, and complex 2 as a monohydrate. The V atoms in the complexes are in octahedral coordination. In the crystal structure of 1·MeOH, the vanadium complexes are linked by methanol solvate molecules through intermolecular O–H∙∙∙N and O–H∙∙∙O hydrogen bonds to form chains along the c axis. In the crystal structure of 2·H2O, the vanadium complexes are linked by water molecules through intermolecular O–H∙∙∙O hydrogen bonds, to form 1D chains along the a axis. The chains are further linked through intermolecular O–H∙∙∙N and O–H∙∙∙O hydrogen bonds in the c direction to form 2D layers. The antimicrobial activities of the complexes against K. pneumoniae, S. aureus, P. aeroginosa, E. coli, and B. subtilis were investigated.

Metal-organic complex hybrid materials constructed from carboxylate ligands and hydrazone ligands have exhibited potential application in many fields. In order to enrich the applications of the metai-organic complex materials, a new hydrazone ligand contains carboxylate group, 2-carboxybenzaldehyde-p-toluenesulfonyl hydrazone (L1), and its Cu(II) complex (C2), have been prepared. The structure of L1 was determined by elemental analysis, IR spectra and single crystal X-ray diffraction, and the composition of Cu(II) complex (C2) has also been determined by elemental analysis, IR and UV spectra. The catalytic activity for A3 coupling reaction of benzaldehyde, piperidine, and phenylacetylene has been investigated. The results show that Cu(II) complex displays a 100 % selectivity to the product of propargylamine during A3 coupling reaction and benzaldehyde conversions were 95.3, 94.2, and 93.4 % at 120 °C for 12 h in the first, second, and third reaction cycles, respectively.

We report the synthesis of Cu(II) complexes with hydrazone ligands, 2-[(6-Nitro-benzothiazole-2-yl)hydrazonomethyl]-4,6-dichloro-phenol (BHD5) and 2-[(6-Nitro-benzothiazole-2-yl)-hydrazonomethyl]- 4-chlorophenol (BH5C). The synthesized compounds were characterized using elemental analyses, FT-IR, UV-Vis, 1HNMR, mass spectra, molar conductance and TGA. The stoichiometry of the copper complexes as 1:1[M:L] ratio and ligand behave as tridentate moiety with NNO donor atoms toward to the metal ion. The complexes have been assigned a tetrahedral geometry. The synthesized ligands and their copper complexes were screened for antibacterial activities against Gram-positive bacteria (Bacillus subtilis), Gram-negative bacteria (Salmonella typhi) and two funguses (Candida tropicalis and Kluyveromyces marxianus). The DPPH antioxidant activity shows that the copper complexes have a promising biological activity than their parent ligand. [ABSTRACT FROM AUTHOR]

Two dinuclear complexes [M2(H2L)2](ClO4)4·2MeCN (M = Co for Co2 and Fe for Fe2) were synthesized using a symmetric hydrazone ligand with the metal ions in an N6 coordination environment. The crystal structures and magnetic properties were determined by single-crystal X-ray diffraction and magnetic susceptibility measurements. The crystal structure study revealed that the spin centers were all in the high-spin state with a distorted octahedron (Oh) geometry. Dynamic magnetic properties measurements revealed that complex Co2 exhibited field-induced single-molecule magnet properties with two-step relaxation in which the fast relaxation path was from QTM and the slow relaxation path from the thermal relaxation under an applied field.

The reaction of tetradentate hydrazone ligand H2babh with Cu(CH3COO)2 in methanol solvent leads to the formation of the mono-nuclear complex [Cu(babh)]. However, on being dissolved in dichloromethane solvent and on addition of ethanol solvent, a dinuclear complex of [Cu2(m1,3-babh)2(C2H5OH)2] is obtained. The X-ray crystallography indicates that the dinuclear helical complex formation is caused due to the unsymmetrical twisting of the H2babh ligand. One oxygen and two nitrogen atoms from the ligand and one oxygen atom from the other ligand coordinate to each copper(II) center. Both the copper(II) centers in a dinuclear unit are penta-coordinate with a slightly distorted square pyramidal geometry. The IR spectra of mono- and dinuclear copper(II) complexes have different bands. The absorption spectra of mono- and di-nuclear complexes are quite similar in methanol solvent. However, the electronic absorption spectra of the two complexes are basically different in the solid state.

Two new structurally similar oxidovanadium(V) complexes [VOL1L] (1) and [VOL2L] (2) (L = acetohydroxamate) derived from N′-(5-bromo-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L1) and N′-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) hydrazones are prepared and characterized by elemental analyses, FT-IR, 1H NMR, and single crystal X-ray diffraction (CIF files CCDC Nos. 1859442 (1) and 1859446 (2)). The V atoms in the complexes are in the octahedral coordination, with hydrazones behaving as binegative donors and acetohydroxamate acting as a mononegative ligand. The complexes function as effective olefin epoxidation catalysts. [ABSTRACT FROM AUTHOR]

Reaction of VO(acac)2 with N’-(3-bromo-5-chloro-2-hydroxybenzylidene)-3-methylbenzohydrazide (H2L) in methanol afforded a new mononuclear vanadium(V) complex, [VOL(OMe)(MeOH)]. Structure of the complex has been characterized by physico-chemical methods and single-crystal X-ray diffraction. The complex crystallizes as the monoclinic space group P21/c, with unit cell dimensions a = 13.1345(10) Å, b = 18.6279(14) Å, c = 7.8983(8) Å, β = 90.248(2)º, V = 1932.4(3) Å3, Z = 4, R1 = 0.0963, wR2 = 0.2213, S = 1.113. X-ray analysis indicated that the V atom in the complex is in octahedral coordination. The insulin-like activity of the complex was studied.

Two new Zn(II) complexes with tridentate hydrazone-based ligands (condensation products of 2-acetylthiazole) were synthesized and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy and single crystal X-ray diffraction methods. The complexes 1, 2 and recently synthesized [ZnL3(NCS)2] (L3 = (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium) complex 3 were tested as potential catalysts for the ketone-amine-alkyne (KA2) coupling reaction. The gas-phase geometry optimization of newly synthesized and characterized Zn(II) complexes has been computed at the density functional theory (DFT)/B3LYP/6–31G level of theory, while the highest occupied molecular orbital and lowest unoccupied molecular orbital (HOMO and LUMO) energies were calculated within the time-dependent density functional theory (TD-DFT) at B3LYP/6-31G and B3LYP/6-311G(d,p) levels of theory. From the energies of frontier molecular orbitals (HOMO–LUMO), the reactivity descriptors, such as chemical potential (μ), hardness (η), softness (S), electronegativity (χ) and electrophilicity index (ω) have been calculated. The energetic behavior of the investigated compounds (1 and 2) has been examined in gas phase and solvent media using the polarizable continuum model. For comparison reasons, the same calculations have been performed for recently synthesized [ZnL3(NCS)2] complex 3. DFT results show that compound 1 has the smaller frontier orbital gap so, it is more polarizable and is associated with a higher chemical reactivity, low kinetic stability and is termed as soft molecule.

The isothiocyanato Zn(II) complex (1) and mixed isothiocyanato/thiocyanato Cd(II) complex (2) with the condensation product of 2-acetylpyridine and trimethylammoniumacetohydrazide chloride (Girard’s T reagent) (HLCl) were investigated both experimentally and theoretically. The crystal structures of both complexes showed tridentate N2O coordination of hydrazine ligand. In complex 1 square-pyramidal coordination surrounding of Zn(II) consists of deprotonated hydrazone ligand and two isothiocyanato ligands, while in octahedral Cd(II) complex ligand is coordinated without deprotonation as a positively charged species and coordination geometry is completed with two N-coordinated and one S-coordinated NCS− anions. NMR spectroscopy and molar conductivity results for Cd(II) and Zn(II) complexes indicated their instability in solution. DFT calculations were performed to explain coordination preference and stability of complexes 1 and 2 in solid state and in solution. The obtained Cd(II) complex is the first reported mononuclear pseudohalide/halide Cd(II) complex with quinoline-/pyridine-based hydrazone ligands possessing octahedral geometry in solid state. In this complex, H-bonding has significant impact on coordination number and supramolecular assembly in solid state. [ABSTRACT FROM AUTHOR]

A new dioxomolybdenum (VI) complex with tridentate hydrazone Schiff base ligand (H2L) derived from 2‐hydroxy‐5‐nitrobenzaldehyde and benzhydrazide was synthesized and designated as [MoO2L (DMF)]·2H2O. The Fe3O4@SiO2‐CPS‐L‐MoO2 (EtOH) nanocatalyst was successfully prepared by grafting H2L ligand on modified Fe3O4 nanoparticles followed by reacting with MoO2 (acac)2. The complex and nanocatalyst were characterized by various techniques such as elemental analysis, mass, FT‐IR, UV–Vis, 1H NMR, 13C{1H}‐NMR, TGA, XRD, XPS, TEM, SEM and VSM. The catalytic activity of [MoO2L (DMF)]2H2O and Fe3O4@SiO2‐CPS‐L‐MoO2 (EtOH) were evaluated for the oxidation of various alkenes (cyclooctene, norbornene, cyclohexene, styrene and α‐methyl styrene) in the presence of tert‐butylhydroperoxide as oxidant. The results revealed that the catalysts were especially efficient for oxidation of cyclooctene and norbornene with 100% selectivity towards corresponding epoxide product. Fe3O4@SiO2‐CPS‐L‐MoO2 (EtOH) showed higher catalytic activity, shorter reaction time and higher turnover number (TON) compared with homogeneous complex [MoO2L (DMF)]·2H2O. Moreover, simple magnetic recovery from the reaction mixture and reuse for several times with no significant loss in activity were other advantages of the nanocatalyst. [ABSTRACT FROM AUTHOR]

The reaction of [VO(acac)2] (where acac = acetylacetonate), benzohydroxamic acid (HL) with N′-(3,5-dichloro-2-hydroxybenzylidene)nicotinohydrazide (H2L1) and N′-(2-hydroxy-4-methoxybenzylidene)-3-nitrobenzohydrazide (H2L2) in methanol affords methanol-coordinated mononuclear oxovanadium(V) complexes [VOL1L] (1) and [VOL2L]·MeOH (2), respectively. Crystal and molecular structures of the complexes are determined by the single crystal X-ray diffraction method. The complexes were further characterized by the elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligands coordinate to the VO core through enolate oxygen, phenolate oxygen, and azomethine nitrogen atoms, and the benzohydroxamate ligands coordinate to the VO core through the carbonyl oxygen and hydroxy oxygen atoms. The V atoms in the complexes are in the octahedral coordination. The thermal stability of the complexes are also studied. [ABSTRACT FROM AUTHOR]

For the first time, a new Cu(II) complex including pyrazine (pyz) and a tridentate O,N,O-donor hydrazone ligand formulated as Cu(L)(pyz)(CH3OH)]+ (1) (LH=[CF3C(OH)=CH-C(CH3)=N-NH-CO-C6H4(OH)]) (CuClC17H18F3N4O4) has been investigated using density functional theory (DFT) methods. The DFT approaches have been performed by applying B3LYP/LANL2DZ/6-311 + G(d, p) and full potential linearized augmented plane wave (FP-LAPW) methods. The complex belongs to triclinic crystallographic system with space group of P1, Z = 2. Selected 1 as monomeric unit (1-mon) through a variety of non-covalent interactions containing hydrogen bonds (HBs) and π-stacking, constructs a 2-D coordination polymeric plane. The dispersion corrected density functional theory (DFT-D) calculations indicate that the conventional O-H···N and the non-conventional C-H···F HBs, govern the related network (1-net) formation. The calculated-B3LYP/LANL2DZ/6-311 + G(d, p) electronic spectrum in gas phase in good agreement with the experimental one shows five major bands in the range of 268-582 nm that could be assigned to MLCT and LLCT transitions with n → π* character. Calculated optoelectronic spectra by FP-LAPW show that Cu-3d state play key role in optical transitions and plasma wavelength of 243 nm found for this studied compound. [ABSTRACT FROM AUTHOR]

Reaction of [MoO2(acac)2] (where acac = acetylacetonate) with N’-(2-hydroxy-4-diethaylaminobenzylidene)-4-hydroxybenzohydrazide (H2L) in methanol afforded a methanol-coordinated mononuclear molybdenum(VI) oxo complex, [MoO2L(MeOH)]. Crystal and molecular structure of the complex were determined by single crystal X-ray diffraction method. The complex was further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligand coordinates to the MoO2 core through enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atom in the complex is in octahedral coordination. Thermal stability of the complex has also been studied. DOI: http://dx.doi.org/10.4314/bcse.v28i3.10

Two new oxovanadium(V) complexes, [VOL(OCH)(CHOH)] ( I) and [VOL(OCH)] ( II), where L and L are the di-anionic form of N'-[1-(5-fluoro-2-hydroxyphenyl)methylidene]nicotinohydrazide and N'-(5-fluoro-2-hydroxybenzylidene)-2-hydroxynaphthylhydrazide, respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination (CIF files CCDC nos. 891852 ( I), 891853 ( II)). The crystal of I is monoclinic: space group P2/ c, a = 8.061(1), b = 15.293(2), c = 13.471(2) Å, ß = 92.595(2)°, V = 1658.8(4) Å, Z = 4. The crystal of II is monoclinic: space group P2/ n, a = 7.4454(9), b = 8.0833(9), c = 28.906(2) Å, ß = 92.644(2)°, V = 1737.8(3) Å, Z = 4. The V atom in I is in an octahedral coordination, and that in II is in a square-pyramidal coordination. The antibacterial activity of the compounds against various bacteria was assayed. [ABSTRACT FROM AUTHOR]

Two new oxidovanadium(V) complexes with the general formula [VOL(bha)], where L represents the deprotonated hydrazone ligands 2-hydroxy-N'-(4-methoxybenzylidene)naphthohydrazide (H2L1) for1andN'-(2-chlorobenzylidene)-2-hydroxynaphthohydrazide (H2L2) for2, and bha represents the monoanionic form of benzohydroxamic acid (Hbha), have been prepared and characterized by elemental analysis, infrared and UV-Vis spectra, and thermal behavior. Structures of the complexes have been further determined by single-crystal X-ray diffraction. The V atoms in the complexes are coordinated by the three donor atoms of the hydrazone ligands, the oxygen atoms of the benzohydroxamate ligands, and oxido oxygen atoms, constituting octahedral coordination spheres. [ABSTRACT FROM AUTHOR]

New octahedral Ruthenium(II) complexes of the general composition [Ru(bpy) 2 (L)]Cl containing aroyl hydrazone Schiff base ligands ( L ) (where bpy = bipyridine, L = 4-(( E )-(furan-2-carboylimino)methyl)benzoic acid ( L1 ), 4-(( E )-(4-methoxybenzoylimino)methyl)benzoic acid ( L2 ) and 4-(( E )-(4-nitrobenzoylimino)methyl)benzoic acid ( L3 )) have been synthesized. All the three complexes have been characterized by various physico-chemical and spectroscopic methods. The molecular structure of L1 and L2 were determined by single crystal X-ray diffraction method. IR study shows that the substituted aroylhydrazone ligands behave as a monoanionic bidentate O and N donors ( L ) coordinates to ruthenium via the azomethine nitrogen and the deprotonated amide oxygen. Photophysical and electrochemical studies were carried out and the structures of the synthesized complex were optimized using density functional theory (DFT). The molecular geometry, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) energies and Mulliken atomic charges and molecular electrostatic potential (MEP) of the molecules are determined at the B3LYP method and standard 6-311++G (d,p) basis set starting from optimized geometry. [ABSTRACT FROM AUTHOR]

A new oxidovanadium(V) complex, [VO(L)Cl 2 ] ( 1 ), is synthesized by the reaction of VOCl 3 with ( E )- N ′-(phenyl(pyridin-2-yl)methylene)isonicotinhydrazide (HL) in chloroform as a solvent. The complex is characterized by elemental analysis, spectroscopic methods (FT-IR, UV–vis), and its structure is determined by single crystal X-ray diffraction analysis. X-ray studies reveal a mononuclear complex of V(V) with the hydrazone ligand coordinated to the V(V) center as a tridentate mononegative ligand. This complex is used as a catalyst precursor for oxidation of olefins and sulfides in the presence of hydrogenperoxide (H 2 O 2 ) as a green oxidant. The effect of various parameters is studied including the amount of the catalyst, temperature and solvent. The results show the system corresponds to an active and selective catalyst for oxidation of cyclooctene and thioanisole. [ABSTRACT FROM AUTHOR]

Three mononuclear Cu(II) complexes Cu(HL 1 )Cl 2 ( 1 ), Cu(HL 2 )Cl 2 ( 2 ), and Cu(L 3 )SCN ( 3 ) have been synthesized based on chelating hydrazone ligands HL 1 , HL 2 , and HL 3 , respectively. These new compounds gave satisfactory IR-spectroscopic data and were further characterized by elemental and X-ray diffraction analyses. Their urease inhibitory evaluation was tested in vitro against jack bean urease. The results showed that the inhibitory activities of the copper complexes are all superior to the positive reference. Enzyme kinetics studies were undertaken to estimate the inhibition mechanism of the copper complexes. Molecular docking simulations have been performed to rationalize their binding models. In addition, their interactions with serum albumin were also studied. [ABSTRACT FROM AUTHOR]

A new hydrazone ligand, 4-methoxyacetophenone benzoyl hydrazone and its cobalt complex were synthesized and characterized using elemental analysis, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, H NMR spectral data, and powder X-ray diffraction techniques. Moreover, the thermal gravimetric analysis and electrochemical (cyclic voltammetry) properties of the ligand and its complex were investigated. The catalytic ability of the Co-MABH complex as a new metal-organic catalyst in the Fischer-Tropsch reaction was investigated. The CO conversion under the operational conditions T = 100 °C, P = 8 atm and ratio of H/CO = 2 was found to be 50.21 %. The physicochemical characteristics of the catalyst were examined using scanning electron microscopy, and Brunauer-Emmett-Teller analysis at different operational stages. [ABSTRACT FROM AUTHOR]

A new oxovanadium(V) complex, [N'-(3-ethoxy-2-hydroxybenzylidene)-4-fluorobenzohydrazido](quinolin-8-olato)oxovanadium(V), [VO(EFH)(QN)], where EFH is the anion ofN'-(3-ethoxy-2-hydroxybenzylidene)-4-fluorobenzohydrazide, and QN is the anion of 8-hydroxyquinoline, was prepared and characterized by elemental analysis, infrared spectra, thermal analysis and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic space groupP21/n, with unit cell dimensionsa= 8.3921(4) Å,b= 28.200(1) Å,c= 10.0237(5) Å, β = 102.394(1)°,V= 2316.9(2) Å3,Z= 4, GOOF = 1.101,R1= 0.0464, andwR2= 0.1081. The V atom is coordinated by the three donor atoms of EFH and two donor atoms of QN, as well as one oxo oxygen group, forming an octahedral coordination. [ABSTRACT FROM AUTHOR]

Mononuclear transition metal complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a new hydrazone ligand derived from pyrazine-2-carbohydrazide and 2-hydroxyacetophenone have been synthesized. The isolated complexes were characterized by elemental analysis, spectral and analytical methods including elemental analyses, IR, diffuse reflectance, 1 H-NMR, mass spectra, molar conductance, magnetic moment, ESR, XRD, TG and SEM analysis. From the elemental analyses data, the stoichiometry of the complexes was found to be 1:1 (metal:ligand) having the general formulae [M(HL)(Cl)(H 2 O) 2 ], [M = Mn(II), Co(II), Ni(II) and Cu(II)] and [M(L)(H 2 O)], [M = Zn(II) and Cd(II)]. The molar conductance values indicate the nonelectrolytic nature of metal complexes. The IR spectral data suggest that the ligand behaves as tridentate moiety with ONO donor atoms sequence towards central metal ion. The Mn(II), Co(II), Ni(II) and Cu(II) complexes have been assigned a monomeric octahedral geometry whereas tetrahedral to Zn(II) and Cd(II) complexes. The antibacterial and antifungal activities of the ligand and its metal complexes were studied against bacterial species Escherichia coli , Pseudomonas aeruginosa , Staphylococcus aureus , Bacillus subtilis , Enterococcus faecalis and Streptococcus pyogenes and fungi Candida albicans , Aspergillus niger and Aspergillus clavatus . The activity data show that the metal complexes have a promising biological activity comparable with the parent ligand against all bacterial and fungal species. [ABSTRACT FROM AUTHOR]

Vanadium complexes have been proved to possess an interesting insulin-like activity. The reaction of VO(acac) with N′-(3,5-dichloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (HL) in methanol affords a new mononuclear vanadium (V) complex [VOL(OMe)(MeOH)]. The structure of the complex is characterized by physicochemical methods and single crystal X-ray diffraction. The complex crystallizes as the monoclinic space group P2/ n, with unit cell parameters a = 7.830(2) Å, b = 23.225(3) Å, c = 10.635(2) Å, β = 101.947(2)°, V = 1892.1(6) Å, Z = 4, R = 0.0404, wR = 0.0953, S = 1.037. The X-ray analysis indicates that the V atom in the complex is in the octahedral coordination. The insulin-like activity of the complex is studied. [ABSTRACT FROM AUTHOR]

Two new oxovanadium(V) complexes [VOL(HQ)] ( 1) and [VOL(HQ)] ( 2) are prepared by the reaction of [VO(acac)] (where acac = acetylacetonate), 8-hydroxyquinoline (HHQ) with 4-bromo- N′- (3-ethoxy-2-hydroxybenzylidene)benzohydrazide (HL) and 2-bromo- N′-(3-ethoxy-2- hydroxybenzylidene)benzohydrazide (HL), respectively, in methanol. Crystal and molecular structures of the complexes are determined by elemental analysis, infrared spectroscopy, and single crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic space group P2/ c, with unit cell dimensions a = 12.5236(13) Å, b = 22.5260(15) Å, c = 16.7029(13) Å, β = 90.054(2)°, V = 4712.0(7) Å, Z = 8, GOOF = 1.024, R = 0.0586 and wR = 0.0835. Complex 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 7.4344(12) Å, b = 10.8677(16) Å, c = 14.687(2) Å, α = 85.327(5)°, β = 77.357(5)°, γ = 84.896(5)°, V = 1150.9(3) Å3, Z = 2, GOOF = 1.153, R = 0.0917 and wR = 0.3014. The V atoms are in the octahedral coordination. Thermal stability of the complexes is also studied. [ABSTRACT FROM AUTHOR]