Preparation,characterization, DFT calculations and ethylene oligomerization studies of iron(II) complexes bearing 2-(1H-benzimidazol-2-yl)-phenol derivatives

Five 2-(1H-benzimidazol-2-yl)-phenol derivatives including 1H (HL₁), 5-chloro-(HL₂), 5-methyl-(HL₃), 5,6-dichloro-(HL₄), and 5,6-dimethyl-(HL₅) were synthesized by the reaction of their corresponding benzene-1,2-diamine precursors and 2-hydroxybenzaldehyde which subsequently was employed in complexation with Fe(II) to prepare complexes C1–C5, respectively. Indeed, in all complexes, the ligands were coordinated as bidentate, via the C=N nitrogen and hydroxy oxygen atom of benzimidazole moiety and phenol ring, respectively. The compounds were characterized by FTIR, UV–vis, ¹H- and ¹³C-NMR spectropscopy, ICP, and elemental analysis (C, H, and N). The purity of these compounds was determined by melting point (m.p )and TLC. The synthesized ligands and complexes were geometrically optimized by Gaussian09 software at B3LYP/TZVP level of theory and satisfactory theoretical–experimental agreement was achieved for analysis of IR data of the compounds. Catalytic behavior of the iron(II) complexes was investigated for ethylene reactivity. On activation with diethylaluminum chloride (Et₂AlCl), iron(II) complex (C4) showed the highest activity (1686 kg oligomers.mol^?1(Fe).h^?1) for ethylene oligomerization when it contains chlorine substituents and exhibits good selectivity for linear 1-butene. The steric and electronic effects of ligands were investigated in detail on the influence of their catalytic activities.     

Synthesis,structures, and urease inhibition of nickel(II), zinc(II), and cobalt(II) complexes with similar hydroxy-rich Schiff bases

Four new nickel(II), zinc(II), and cobalt(II) complexes, [Zn(L¹)₂]?·?H₂O (1), [Ni(L¹)₂]?·?H₂O (2), [Ni(L²)₂] (3), and [Co(L³)₂]?·?H₂O (4), derived from hydroxy-rich Schiff bases 2-{[1-(5-chloro-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL¹), 2-{[1-(2-hydroxy-3-methoxyphenyl)methylidene]amino}-2-ethylpropane-1,3-diol (HL²), and 2-{[1-(5-bromo-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL³) have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray determination. Each metal in the complexes is six-coordinate in a distorted octahedral coordination. The Schiff bases coordinate to the metal atoms through the imino N, phenolate O, and one hydroxyl O. In the crystal structures of HL¹ and the complexes, molecules are linked through intermolecular O–H···O hydrogen bonds, forming 1-D chains. The urease inhibitory activities of the compounds were evaluated and molecular docking study of the compounds with the Helicobacter pylori urease was performed.     

Sulfanilamide-containing coordination compounds of Cu(II) with isatin and N-methylisatin thiosemicarbazones

Isatin (L¹) and N-methylisatin (L²) β-thiosemicarbazones react in ethanol with Cu(II) chloride and bromide in the presence of sulfanilamide (Streptocid, Sf¹), N-acetylsulfanilamide (Sulfacyl, Sf²), Norsulfazole (Sf³), Aethazolum (Sf⁴), and Sulfadimesine (Sf⁵) to form coordination compounds Cu(Sf^1–5)L^1–2X₂ · nH₂O (X = Cl, Br; n = 2–5). All the complexes have a monomeric structure. Thiosemicarbazones L¹ and L² in these complexes are tridentate O,N,S ligands, and sulfanilamides Sf^1–5 are monodentate ligands. Thermolysis of the substances involves the steps of dehydration (70–95°C) and complete decomposition (410–530°C).     

Sulfanylamide-containing coordination compounds of 3d-elements with 2,4-pentanedione bis-thiosemicarbazone and bis-4-phenylthiosemicarbazone

Thiosemicarbazide and 4-phenylthiosemicarbazide react in ethanol with 2,4-pentanedione in the presence of manganese, cobalt, nickel, copper, and zinc acetates hydrates and streptamin (Sf¹), sulfaethidole (Sf²), and sulfadimidine (Sf³) to form coordination compounds of the composition M(Sf^1–3)(L^1–2) · nH₂O (M = Mn, Co, Ni, Cu, Zn; H₂L¹ is 2,4-pentanedione bis-thiosemicarbazone, H₂L² is 2,4-pentanedione bis-4-phenylthiosemicarbazone; n = 0–6). All the complexes synthesized are monomeric. Thiosemicarbazones (H₂L¹ and H₂L²) behave as twice deprotonated S,N,N,S-tetradentate ligands, while sulfanylamides (Sf^1–3) act as monodentate ones. Thermolysis of these substances proceeds through the stages of dehydration (65–95°C) and complete thermal decomposition (430–560°C). It is found that the complex [Cu(Sf²)(L¹)] · 4H₂O in the concentration 10^?5 M inhibits the growth and fission of 100% cancer cells of the human myeloid leukemia (HL-60).     

Synthesis and structure of new copper(II) coordination compounds with 8-quinoline aldehyde semicarbazones and thiosemicarbazones

Copper(II) salts were reacted with various quinoline aldehyde chalcogensemicarbazones to yield compounds formulated as Cu(HL)X₂ · nH₂O (I: HL = quinoline aldehyde thiosemicarbazone (HL¹), X = ClO₄, n = 2; II: HL = quinoline aldehyde 4-C₂H₅-thiosemicarbazone (HL^1a), X = NO₃, n = 0; III: HL = quinoline aldehyde semicarbazone (HL²), X = ClO₄, n = 3 and IV: HL = quinoline aldehyde 4-Ph-semicarbazone (HL^2a), X = NO₃, n = 1). Regardless of the reagent ratio, the products were compounds having the metal: ligand ratio of 1: 1, where the organic ligand was coordinated tridentate in a molecular form. Single-crystal X-ray diffraction showed that, depending on the chalcogen atom in the organic ligand (S or O), the substituent in the 4th position (at the terminal nitrogen atom), and the specifics of the acido ligand, complexes I–IV had appreciably differing molecular structure organizations. The structures of I and III are formed by a 1D charged coordination polymer, ClO ₄ ^? anions, and water molecules and may be described by the formula [Cu(HL)(H₂O)(ClO₄)] _n (ClO₄) _n · nH₂O. Copper(II) coordination polyhedra in I and II are (4 + 2) and (4 + 1 + 1) tetragonal bipyramids, respectively. In II and IV, the structures are monomeric and can be described as [Cu(HL^1a)(NO₃)₂] with the metal coordination polyhedron shaped as a (4 + 1) tetragonal pyramid in II and as [Cu(HL^2a)(H₂O)(NO₃)](NO₃) with the metal coordination polyhedron shaped as a (3 + 2) trigonal bipyramid in IV. The structure of II is built of molecular complexes, each comprising, apart from ligand HL^1a, two monodentate coordinated NO ₃ ^? groups. The oxygen atom of one anion together with the NNS donor atom set of ligand HL^1a form the base, and the oxygen atom of the other anion is in the apex of the coordination polyhedron. In IV, the structure is ionic and built of NO ₃ ^? anions and [Cu(HL^2a)(H₂O)(NO₃)]⁺ complex cations, where a cationic coordination polyhedron has a trigonal-bipyramidal configuration with organic ligand HL^2a positioned along the long edge. The bipyramidal base is made up by the oxygen atoms of the coordinated water molecule and monodentate nitrato group and the nitrogen atom N2 of the azomethyne group.     

Synthesis and characterization of N -(alky(aryl)carbamothioyl)cyclohexanecarboxamide derivatives and their Ni(II) and Cu(II) complexes

N-(R-carbamothioyl)cyclohexanecarboxamides (R: diethyl, di-n-propyl, di-n-butyl, diphenyl and morpholine-4) and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and NMR methods. N-(diethylcarbamothioyl)cyclohexanecarboxamide, HL¹, C₁₂H₂₂N₂OS, crystallizes in the orthorhombic space group P2₁2₁2₁, with Z = 4, and unit cell parameters, a = 6.6925(13) Å, b = 9.0457(18) Å, c = 22.728(5) Å. The conformation of the HL¹ molecule with respect to the thiocarbonyl and carbonyl moieties is twisted, as reflected by the torsion angles O1–C6–N2–C5, C6–N2–C5–N1 and S1–C5–N2–C6 of 1.68°, ?67.47° and 115.50°, respectively. The structure of HL¹ also shows a delocalization of the π electrons of the thiocarbonyl group over the C–N bonds. The ring puckering analysis shows that the cyclohexane ring has a chair conformation. The bis(N-(morpholine-4-carbonothioyl)cyclohexane carboxamido)nickel(II) complex, Ni(L⁵)₂, C₂₄H₃₈N₄NiO₄S₂, crystallizes in the monoclinic space group P2₁/c, with Z = 4, and unit cell parameters, a = 16.919(3) Å, b = 8.3659(17) Å, c = 19.654(4) Å, β = 107.43(3)°. Ni(L⁵)₂ is a cis-complex with a slightly distorted square-planar coordination of the central nickel by two oxygen and two sulfur atoms.     

X-ray crystal structure of a distorted tetrahedral cluster in the salt [(Ph3P)4Au4N]+ BF4−. Geometrical indication of stable electronic configurations in post-transition metal complexes and the magic number 18-e in centred gold clusters

According to an X-ray investigation (?120°C, λ(Mo-K_α), 6815 reflections, space group P2₁/c, Z = 4, R = 0.068), the cation of the tetraaurated ammonium salt [(Ph₃PAu)₄N]⁺ BF₄^? can be considered as a distorted tetrahedral Au₄(N) cluster built up of four linearly coordinated Au atoms with an interstitial N atom (AuAu 3.012–3.504 Å, AuN 1.93–2.10 Å). On the basis of the structural data on 14-, 16- and 18-electron mononuclear post-transition metal complexes, the magic number of 18 skeletal electrons can be suggested for [Au_nL_{n ? 1}]^m+ clusters with an interstitial Au atom and a quasi-spherical peripheral Au_{n ? 1} polyhedron.     

Cobalt complexes based on 2-(1H-benzimidazol-2-yl)-phenol derivatives: preparation,spectral studies,DFT calculations and catalytic behavior toward ethylene oligomerization

In this study, five novel Co(II) complexes of 2-(1H-benzimidazol-2-yl)-phenol derivatives (HL_x: x = 1–5) have been synthesized and characterized. The general formula for complexes C1 and C2 is K₂[Co(HL_1,2)₂Cl₂]·H₂O, for complex C3 K₂[Co(HL₃)₂Cl₂], and for complexes C4 and C5 [Co(HL_4,5)₂]. In all complexes, the ligands are coordinated as bidentate, via one imine nitrogen and the phenolate oxygen atoms. The structures of the compounds were characterized by FT-IR, UV–vis, ¹H, ¹³C NMR spectroscopies, ICP and elemental analysis (C, H, and N). The purity of these compounds was ascertained by melting point (m.p.) and TLC. Geometry optimization of the studied complexes was done by Gaussian09 software at B3LYP/TZVP level of theory and satisfactory theoretical–experimental agreement was achieved for NMR and IR spectra of the compounds. Based on the combined experimental and theoretical studies, six-coordinate octahedral structures have been proposed for complexes C1–C3, while complexes C4 and C5 had distorted tetrahedral geometry. All complexes were activated with diethylaluminum chloride (Et₂AlCl), cobalt(II) complexes containing bulky methyl groups in the aryl moiety show high catalytic activities (1774 kg?mol^?1(Co)?h^?1) for ethylene oligomerization. The oligomers obtained from the cobalt complexes exhibit good selectivity for linear 1-butene and 1-hexene. Results revealed that both the steric and electronic effects of ligands strongly affect the catalytic activities and the properties of the catalytic products.     

Synthesis and spectral studies of some new dimeric [(μ-Cl)2M2(L)2 · xTHF] [M = Zn(II) and Hg(II)] complexes containing Schiff-base ligands

A series of binuclear Schiff-base complexes of zinc(II) and mercury(II) containing bidentate ligands (HL) [HL?=?salicylidene-2-methyl-1-aminobenzene (HL¹), salicylidene-2-aminopyridine (HL²), and salicylidene-3-nitro-1-aminobenzene (HL³)] with “N” and “O” donors have been synthesized by simple metathetic reactions of anhydrous metal chlorides with sodium salts of Schiff bases (in tetrahydrofuran (THF)/MeOH) in equimolar ratio to produce [(µ-Cl)₂M₂(L)₂?·?xTHF] [where M?=?Zn(II) and Hg(II); L?=?HL¹, HL², and HL³; x?=?0 for (1), (4), (6) and x?=?2 for (2), (3), (5)]. The main emphasis on the complexes [(µ-Cl)₂M₂(L)₂?·?2THF] (2), (3), and (5) is given due to their five-coordinate environment around metal ions. The complexes have been characterized by elemental analyses (M, Cl, C, H, N), melting point, and spectral (FT-IR, ¹H-NMR, and ¹³C-NMR) studies. The structural composition of the complexes has been determined by FAB-MS spectral studies. FAB-MS showed the isotopic molecular ion peak [M⁺] and fragments supporting the formulation. Powder X-ray diffraction study of 6 is also reported showing the crystallite size (404.5?Å) of the complex.     

Co(III) complexes with optically active bis(menthane), pinano-para-menthane, carano-para-menthane, and bis(carane) propylenediaminodioximes

Novel optical ligands bis(menthane) (H₂L¹), pinano-para-menthane (H₂L²), and carano-para-menthane (H₂L³) propylenediaminodioximes are obtained. Diamagentic Co(III) complexes of the composition Co(HL¹)Cl₂ (I), Co(HL²)Cl₂ (II), Co(HL³)Cl₂ (III), and Co(HL⁴)Cl₂ · H₂O(IV) are synthesized by reactions of CoCl₂ with H₂L¹, H₂L², H₂L³ and bis(carane) propylenediaminodioxime (H₂L⁴) in ethanol in air. The crystal and molecular structures of compound I is determined by X-ray diffraction analysis. The crystals are monoclinic with the unit cell parameters a = 7.8385(3) Å, b = 11.4074(6) Å, c = 14.9509(6) Å, β = 104.278(2)°, V = 1295.57(10) ų, Z = 2, ρ(calcd) = 1.367 g/cm³, F(000) = 564, M = 533.41, space group P2₁. The crystal structure of complex I consists of individual mononuclear molecules. The Co³⁺ ion coordinates four N atoms of tetradentate cycle-forming anionic ligand and two Cl atoms. The coordination polyhedron of Cl₂N₄ is a distorted octahedron. The ¹³C and ¹H NMR spectra of the complexes synthesized confirm coordination of four N atoms of a ligand.     

Synthesis,structure, and properties of coordination compounds of copper(II) acetate with substituted 2-{[2-(2-hydroxyethylamino)ethylimino]methyl}phenol

Salicylic, 5-chloro-5-bromo-5-nitro-, 3-methoxysalicylic, 2-hydroxy-1-naphthoic aldehydes and 2,3-, 2,4-, and 2,5-dihydroxybenzaldehyde were shown to react in ethanol with 2-(2-aminoethylamino)ethanol in the presence of copper acetate hydrate forming coordination compounds Cu(L^1-9)CH₃COO {HL^1-8, 2-([2-(2-hydroxyethylamino)ethylimino]methyl}phenol (HL¹) and respective chloro(HL²), bromo- (HL³), nitro- (HL⁴), methoxy- (HL⁸), or hydroxy-substituted (HL^5-7); HL⁹, 2-{[2-(2-hydroxyethylamine)ethylimino] methylnaphthol)}. Structure of the complex Cu(L³)CH₃COO was determined by X-ray diffraction analysis. Coordination polyhedron of its central atom is a distorted tetragonal bipyramid with (4+1+1) modes of coordinating the copper atom. The bipyramid base is formed by the atoms of phenol oxygen and of azomethine and imine nitrogen atoms of the ligand (HL³) and the oxygen atom of the acetate ion. Axial apices of the bipyramid are occupied by the alcohol oxygen atoms of the azomethine (HL³) and the second oxygen atom of the acetate ion. Other complexes are also of monomer structure. Azomethines (HL^1-9) behave as monodeprotonated tetradentate O,N,N,O ligands. The thermolysis of substances includes a stage of complete thermal decomposition (360–530°C). Synthesized complexes show selective antimicrobial activity against a series of standard strains of Staphylococcus aureus and E. coli at the concentration in the range of 75–300 μg ml⁻¹.     

Cu(II) and Co(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole: Synthesis and study

The Cu(II) and Co(II) complexes with 3,5-diphenyl-4-amino-1,2,4-triazole (L) of the composition CuLA₂ · H₂O (A = Cl^?, Br^?), CuL₂A₂ (A = Cl^?, Br^?, NO ₃ ^? ), CoL₂A₂ · nH₂O (A = Cl^?, n = 1; A = NCS^?, n = 0) are synthesized. In these complexes, the ligand L is coordinated to a metal in monodentate mode through the heterocyclic N(1) atom. The Cu: L = 1: 1 complexes have binuclear structures with the anions acting as bridges, whereas the M: L = 1: 2 complexes are mononuclear. Both ferro-and antiferromagnetic exchange interactions are detected for the synthesized complexes.     

Cobalt, nickel, and copper coordination compounds with 3-phenylpropenal benzoylhydrazone

3-Phenylpropenal benzoylhydrazone (HL) reacts with cobalt, nickel, and copper chlorides, nitrates, and acetates to give coordination compounds MX₂ · nH₂O [M = Co, Ni, Cu; X = Cl, NO₃, HL = C₆H₅CH=CHCH=NNHC(O)C₆H₅; n = 0, 2] and ML₂ · nH₂O (M = Co, Ni, Cu; n = 1–3). Complexes MALCI (M = Co, Ni, Cu) were obtained by these reactions in the presence of amines (A = C₅H₅N, 2-CH₃C₅H₄N, 3-CH₃C₅H₄N, 4-CH₃C₅H₄N). All the compounds have a monomeric structure. Azomethine (HL) in them behaves as a bidentate N,O-ligand. Thermolysis of the complexes involves the stages of dehydration (70–90°C), deaquation (145–155°C) or deamination (145–185°C), and complete thermal decomposition (330–490°C).     

Synthesis,structure, geometrical,and spectral characteristics of the (HL<Superscript><Emphasis Type="Italic">n</Emphasis></Superscript>)<Subscript>2</Subscript>[CuCl<Subscript>4</Subscript>] complexes. Crystal and molecular structure of bis(2-methylimidazolium) tetrachlorocuprate(II)

The (HL ⁿ )₂[CuCl₄] complexes (where L ⁿ are organic nitrogen-containing bases with n = 1–6) were synthesized. The crystal and molecular structures of bis(2-methylimidazolium) tetrachlorocuprate(II), (HL¹)₂[CuCl₄], were determined. The spectral characteristics of the complexes were measured. The correlations between the degree of distortion of the crystal structure of the tetrachlorocuprate anion and the hydrogen bond parameters and the spectral characteristics of compounds were obtained.     

Coordination compounds of cobalt,nickel, copper,and zinc with N 1,N 2-bis(pyridin-2-ylmethylidene)benzene-1,2-diamine and its derivatives

o-Phenylenediamine reacts with 2-formyl-, 2-acetyl-, or 2-benzoylpyridine in ethanol in the presence of cobalt, nickel, copper, or zinc chlorides to form monomeric complexes ML^1–3Cl₂·nH₂O {M = Co, Ni, Cu, Zn; L¹ = N ¹,N ²-bis(pyridin-2-ymethylidene)benzene-1,2-diamine, L² = N ¹,N ²-bis(pyridin-2-ylethylidene) benzene-1,2-diamine, L³ = N ¹,N ²-bis[phenyl(pyridin-2-yl)methylidene]benzene-1,2-diamine; n = 0–3}. The condensation products (L¹–L³) act in the complexes as tetradentate N,N,N,N-ligands. Thermolysis of the complexes occurs in two stages: dehydration (70–95°C) and complete degradation (320–450°C). At concentrations of 10^?5–10^?7 M, the complexes inhibit in vitro growth and proliferation of HL-60 human promyelocytic leukemia cells.     

Synthesis,characterization, DNA-binding,and antioxidant activities of four copper(II) complexes containing N-(3-hydroxybenzyl)-amino amide ligands

Four new substituted amino acid ligands, N-(3-hydroxybenzyl)-glycine acid (HL₁), N-(3-hydroxybenzyl)-alanine acid (HL₂), N-(3-hydroxybenzyl)-phenylalanine acid (HL₃), and N-(3-hydroxybenzyl)-leucine acid (HL₄), were synthesized and characterized on the basis of ¹H NMR, IR, ESI-MS, and elemental analyses. The crystal structures of their copper(II) complexes [Cu(L₁)₂]·2H₂O (1), [Cu(L₂)₂(H₂O)] (2), [Cu(L₃)₂(CH₃OH)] (3), and [Cu(L₄)₂(H₂O)]·H₂O (4) were determined by X-ray diffraction analysis. The ligands coordinate with copper(II) through secondary amine and carboxylate in all complexes. In 2, 3, and 4, additional water or methanol coordinates, completing a distorted tetragonal pyramidal coordination geometry around copper. Fluorescence titration spectra, electronic absorption titration spectra, and EB displacement indicate that all the complexes bind to CT-DNA. Intrinsic binding constants of the copper(II) complexes with CT-DNA are 1.32?×?10^6?M^?1, 4.32?×?10^5?M^?1, 5.00?×?10^5?M^?1, and 5.70?×?10^4?M^?1 for 1, 2, 3, and 4, respectively. Antioxidant activities of the compounds have been investigated by spectrophotometric measurements. The results show that the Cu(II) complexes have similar superoxide dismutase activity to that of native Cu, Zn-SOD.     

Synthesis,crystal structures,and antibacterial activities of Schiff base nickel(II) and cadmium(II) complexes with tridentate Schiff bases

Reaction of tridentate Schiff bases with nickel and cadmium salts in methanol afforded two new mononuclear complexes, [Ni(L¹)₂] (I) and [Cd(L²)₂] (II), where L¹ and L² are the anions of 2-bromo-4-chloro-6-[(3-dimethylaminopropylimino)methyl]phenol (HL¹) and 2-bromo-4-chloro-6-[(3-morpholin-4-ylpropylimino)methyl]phenol (HL²), respectively. The complexes were characterized by singlecrystal X-ray diffraction (CIF files CCDC nos. 1428653 (I) and 1428654 for (II)), FT-IR, and elemental analysis. Complex I crystallizes in the monoclinic space group P2 ₁/c, with a = 8.8216(8), b = 14.0424(8), c = 11.8687(12) Å, β = 111.238(2)°, V = 1370.4(2) ų, Z = 2. Complex II crystallizes in the monoclinic space group P2 ₁/n, with a = 9.6774(4), b = 15.8970(6), c = 20.3144(7) Å, β = 90.408(2)°, V = 3125.1(2) ų, Z = 4. The metal atoms in the complexes are coordinated by two tridentate Schiff base ligands, forming octahedral coordination. The free Schiff bases and the complexes were assayed for antibacterial activities. Both complexes are more active against the bacteria than the free Schiff bases. Complex II has the MIC value of 0.39 μg mL^–1 against Bacillus subtilis.     

Vanadyl(IV) complexes of 4-alkoxy substituted [N,O] donor salicylaldimine Schiff bases derived from chloro-/nitro-aniline: synthesis,mesomorphism, and DFT study

Oxovanadium(IV)-Schiff-base complexes, [VOL₂] {L?=?N,N′-bis-(4-X-amino phenyl (4′-n-alkoxy)-salicylaldiminato), n?=?10, 18; X?=?Cl, NO₂}, have been synthesized from the interaction of vanadyl (VO²⁺) and the bidentate [N,O] donor in methanol/ethanol. The compounds were characterized by FT–IR, ¹H- and ¹³C-NMR, FAB-mass spectra, elemental analyses, and solution electrical conductivity. Mesomorphic behavior of the ligands and their vanadyl complexes were probed by polarizing optical microscopy and differential scanning calorimetry. The compounds are thermally stable and exhibit enantiotropic smectic A mesomorphism over the temperature range of 57–231°C. The mesophase–isotropic transition temperatures for the complexes are much higher than the ligands. Melting and clearing points of the compounds did not show any definitive trend with regards to alkoxy chain length or electronegative substituent. Variable temperature magnetic susceptibility measurements of the vanadyl complexes clearly show the absence of exchange interactions among the vanadyl spin centers. Non-electrolytic natures of the complexes were shown by conductometric measurements. A ν(V=O) of ～970?cm^?1 corroborated the absence of any V=O?···?V=O interactions. Density functional theory study carried out using DMol3 at BLYP/DNP level to determine the energy-optimized structure revealed a distorted square pyramidal geometry for the vanadyl complexes.     

New hydrogen-bonded dimeric and polymeric gold(I) complexes of the heterodifunctional ligand Ph2PNHP(O)Ph2

The preparation of several new gold(I) complexes by chloride metathesis of [AuCl(HL)] [HL=Ph₂PNHP(O)Ph₂] with either HL or K[Ph₂P(E)NP(E)Ph₂] (E=S or Se) is described. All compounds were characterised by a combination of ³¹P{¹H}, ¹H and IR spectroscopy, microanalysis and X-ray crystallography. X-ray structural studies reveal that [Au(HL)₂]Cl [monoclinic, space group P2₁/c, a=9.0726(3) Å, b=21.0847(6) Å, c=12.0131(3) Å, β=105.1090(10)°, V=2219 ų, Z=2, final R=3.97] forms a one dimensional polymeric structure in which alternating [Au(HL)₂]⁺ and Cl⁻ ions are linked through intermolecular N–H⋯Cl hydrogen-bonding. In contrast the three-co-ordinate compound [Au{Ph₂P(Se)NP(Se)Ph₂-Se,Se′}(HL)] [monoclinic, space group P2₁/a, a=21.6752(5) Å, b=9.1200(10) Å, c=24.0742(7) Å, β=106.080(2)°, V=4573 ų, Z=4, final R=8.94] forms hydrogen-bonded dimer pairs analogous to that previously observed in non-complexed HL. The X-ray crystal structure of the gold(I) precursor [AuCl(HL)] has also been determined: monoclinic, space group P2₁/c, a=10.217(8) Å, b=23.256(5) Å, c=20.086(5) Å, β=101.15(4)°, V=4683 ų, Z=8, final R=5.2. The X-ray crystal structure reveals intermolecular N–H⋯OP hydrogen-bonding between adjacent [AuCl(HL)] molecules forming infinite chains.     

Synthesis,crystal structures,and biological property of dinuclear oxovanadium(V) complexes derived from tridentate Schiff bases

A pair of structurally similar dinuclear oxovanadium(V) complexes, [VO₂L¹]₂ (I) and [VO₂L²]₂ (II), where L¹ and L² are the mono-anionic form of 2-[(2-isopropylaminoethylimino)methyl]-4-methylphenol (HL¹) and 4-fluoro-2-[(2-isopropylaminoethylimino)methyl]phenol (HL²), respectively, have been synthesized and characterized by elemental analysis, FT-IR spectra, and single crystal X-ray determination. The crystal of I is monoclinic: space group P2₁/c, a = 12.528(1), b = 12.266(1), c = 9.432(1) Å, β = 104.814(3)°, V = 1401.2(3) ų, Z = 2. The crystal of I is monoclinic: space group P2₁/n, a = 12.3128(5), b = 6.5124(3), c = 17.1272(7) Å, β = 105.863(1)°, V = 1321.1(1) ų, Z = 2. The V…V distances are 3.210(1) Å in I and 3.219(1) Å in II. The V atoms in the complexes are in octahedral coordination. Biological assay indicates that complex II, bearing fluoro-substitute groups, has stronger antimicrobial activity against most bacteria than complex I which bearing methyl-substitute groups.