A New Method of Synthesis of Azo Schiff Base Ligands with Azo and Azomethine Donors: Synthesis of N-4-Methoxy- benzylidene-2-(3-hydroxyphenylazo)-5-hydroxy- aniline and Its Nickel(II) Complex

A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxy- phenylamine (SB) derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel(II) complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio (M∶L＝1∶2) and suggested a square planar geometry for the complex.     

A new oxidovanadium(Ⅳ) Schiff base complex containing asymmetric tetradentate ONN0O0Schiff base ligand:Synthesis,characterization,crystal structure determination,thermal study and catalytic activity

After synthesis of an asymmetric tetradentate ONN0O0 Schiff base ligand(H2L) followed by reaction of the synthesized H2 L with an equimolar mixture of methanolic solutions of the VO(acac)2, a new oxidovanadium(IV) Schiff base complex(VOL) was synthesized. The Schiff base ligand and its complex were characterized by FT-IR and UV–vis spectra and C, H, N analysis. The crystal structure of VOL was also determined by single crystal X-ray analysis. The VOL complex crystallizes in monoclinic space group Cc. The Schiff base ligand acts as a tetradentate ligand through its two iminic nitrogens and two phenolic and acetylacetonate oxygens. Thermogravimetric analysis of the VOL showed that it decomposes in two steps and converts to mixed vanadium oxides at 477 8C. In addition, thermal decomposition of the VOL complex in air at 660 8C leads to formation of V2O5 nanoparticles with the average size estimated from XRD 49 nm. The catalytic activity of the VOL complex was investigated in the epoxidation reaction and different reaction parameters were optimized. The results showed that the cyclic alkenes were efficiently converted to the corresponding epoxides, whereas the VOL did not appreciably convert the linear alkenes.     

Syntheses,Crystal Structures and Antibacterial Activities of Schiff Base Ligand and Its Nickel(Ⅱ) Complex

A complex [NiL2] was synthesized, in which L, or to be exact, a Schiff base ligand(HL), was derived from the condensation of 1-phenyl-3-methyl-4-phenylacetyl-5-pyrazolone(PMPAP) with L-phenylalanine methyl ester. They were characterized by IR and single-crystal X-ray diffraction. Green block crystals of both ligand and its complex were grown at room temperature. The ligand, which consists of two individual fragments, crystalizes in the P1 space group(a = 5.6268(5), b = 10.6892(11) and c = 19.4869(18) ). The complex crystalizes in the P21 space group(a = 21.4076(18), b = 9.4792(8) and c = 25.287(2) ), which consists of a nickel six-coordinated compound. Every fragment is a distorted octahedron with four oxygen and two nitrogen atoms. The Schiff base ligand(HL) and its complex have been tested in vitro to evaluate their antibacterial activity against bacteria Escherichia Coli and Bacillus subtilis. It is found that the complex has higher activity than the corresponding free Schiff base ligand(HL) against the same bacterial.     

Accelerated Hydrolysis of p-Nitrophenyl Picolinate Catalyzed by Metallomicelle Made from a Novel Macrocyclic Polyamine Copper（Ⅱ） Complex

A copper（Ⅱ） complex 1 of a novel macrocyclic polyamine ligand with hydroxylethyl pendant groups, 4,11-bis（hydroxylethyl）-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane （L） has been synthesized and characterized. Rate enhancement for hydrolysis of p-nitrophenyl picolinate （PNPP） catalyzed by 1 was studied kinetically under Brij35 micellar condition. For comparision, the catalytic activity of corresponding copper（Ⅱ） complex 2 of non-substituted macrocyclic polyamine ligand, 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraaza-cyclotetradecane （L＇） toward the hydrolysis of PNPP was also investigated. The results indicate that the macrocyclic polyamine copper（Ⅱ） complex 1 effectively catalyzed the hydrolysis of PNPP, and the pendant ligand hydroxyl group or deprotonated pendant ligand hydroxyl group can act as catalytically active species in the reaction. A ternary Complex kinetic model involving metal ion, ligand and substrate has been proposed, and the results confirmed the reasonability of such kinetic model.     

Crystal Structure and Inhibitory Activity against Xanthine Oxidase of Bis（μ2- chloro）-chloro-（μ-N,N＇-（2-pyridylmethylene） Furanmethanoamine Copper（II） Complex

A chloro-bridged dinuclear copper（H） complex with ligand 2-pyridylme-thylene- furfurylamine has been synthesized and characterized by single-crystal X-ray diffraction, and its inhibitory activity on xanthine oxidase （XO） was also evaluated. It crystallizes in the triclinic system, space group P 1 with a = 8.0441（16）, b = 8.5663（17）, c = 10.060（2）A, α = 77.52（3）, β = 72.04（3）, γ = 70.12（3）°, V = 615.3（2）A^3, Z = 1, Dc = 1.731 g/cm^3, F（000） = 322, the final R = 0.0401 and wR = 0.0934 for 1971 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the Cu（II） cation is five-coordinated by two N atoms of Schiff base and three Cl anions. The C-H…Cl intermolecular and intramolecular hydrogen bonds connect the molecules to form a three-dimensional network. This copper（II） complex shows more potent inhibitory activity against XO with IC50 = 3.48μM than the standard inhibitor allopurinol.     

Synthesis, Crystal Structure, and Cytotoxic Property of Di（μ1”,1”-azide）bis（4-nitro-2-（3＇-dimethylaminon-propylimino）methylenephenolate）dizinc（Ⅱ）

The title azide-bridged dinuclear Schiff base zinc(Ⅱ) complex [Zn2(C12H16N3O3)2-(μ1,1-N3)2] was prepared and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group F21/n with a = 8.736(2), b = 14.850(3), c = 11.775(2) (A), β = 102.42(3)°, V= 1491.8(5) (A)3, Z= 2, Dc = 1.593 g/cm3, Mr = 715.36, λ(MoKα) = 0.71073 (A), μ = 1.669 mm-1, F(000) = 736, the final R = 0.0338 and wR = 0.0789. A total of 3411 unique reflections were collected, of which 2777 with Ⅰ＞2σ(Ⅰ) were observed. The molecule of the complex is located on a crystallographic inversion centre. Each Zn atom in the complex is five-coordinated by one Schiff base ligand and two bridging azide groups, forming a trigonal bipyramidal configuration. The Zn…Zn distance is 3.328(2) (A). In the crystal structure, molecules are linked through intermolecular C-H…N hydrogen bonds, forming layers parallel to the bc plane. The complex shows low cytotoxic property to both normal and carcinoma cells.     

Solid-phase Synthesis of a Novel Kind of Hydroxylated Heterocyclic Ketene Aminals

An efficient solid-phase synthesis method for novel heterocyclic ketene aminals containing a hydroxyl group has been developed. The loading of the substrate on the resin through the hydroxyl group and the protection of the amine by the Schiff base were the key steps in the synthesis.     

Synthesis and Crystal Structure of the Azo Copper（Ⅱ）-complex

The single crystals of the azo copper(Ⅱ)-complex have been obtained from the solution of the compound dissolved in the ethanol by slow evaporation at room temperature. The structure was successfully determined by single-crystal X-ray diffraction. The crystal is of triclinic system, space group P1 with a = 7.8843(12), b = 11.5998(17), c = 13.955(2) , α = 112.214(2), β = 95.105(2), γ = 97.616(2)o, V = 1157.6(3) 3, Mr = 586.97, Z = 2, F(000) = 600, Dc = 1.684 g/cm3, μ(MoKα) = 1.120 mm-1, the final R = 0.0419 and wR = 0.1259 for 3475 observed reflections with I > 2σ(I). The coordination around copper(II) atom is a slightly distorted square-pyramidal geometry involving [Cu(C16H11N4O8S)(OH)H2O]-cation, one Na+ anion and one C2H5OH solvate molecule. The hydrogen bonds and π···π stacking interactions extend the complex into a three-dimensional framework.     

立方烷型2-羟甲基-N-邻羟基苯亚甲基苯胺四核镍配合物的合成与晶体结构

The tetranuclear cubane-like complex, [NiL（EtOH）]4·0.5EtOH （1） with tridentate Schiff base ligand （H2L= 2-Hydroxymethyl-N-salicylideneaniline） has been synthesized and its crystal structure and spectroscopic properties have been studied. The complex consists of a tetranuclear （NiO）4 cubane core, of which four nickel（Ⅱ） ions are bridged by μ3-alkoxide group and each nickel（Ⅱ） ion is coordinated to three μ3-alkoxide oxygen atoms, one imino nitrogen atom and one phenoxide oxygen atom from Schiff base ligand, and further ligated by one EtOH molecule, completing a distorted octahedral geometry.     

SYNTHESIS OF POLY（3,4-AZOPYRIDYLENE） AND OXYGEN-BINDING AFFINITY OF ITS COMPLEX WITH COBALTPORPHYRIN

Synthesis and characteristics of poly(3,4-azopyridylene) (PAP), conductivity and oxygen-binding affinity of its complex with meso-α,α,α,α-tetrakis(o-pivalamidophenyl) porphyrinatocobalt(Ⅱ) (CoP) were studied. PAP was prepared by oxidative polymerization of 3,4-diaminopyridine (DAP) in DMF solution using CuCl/pyridine as the catalyst. IR and NMR results showed that the peak of amido group in DAP was converted to the azo group in PAP and a π conjugated polymer was synthesized. The average molecular weight of PAP was determined to be 5.0 × 103. The PAP-CoP complex was prepared by complexing the pyridyl group of PAP with the fifth coordination site of CoP in DMF solution. In comparison with the CoP complex with a non-π conjugated polymer, the PAP-CoP complex shows good electroconductivity of 5.8 × 10-6 Scm-1. The PAP-CoP complex displays a reversible change in the UV-Visible absorption spectrum from the deoxy form to the oxy or oxygen-binding one with an isosbestic point, in response to the partial oxygen pressure of the atmosphere. The oxygen-response behavior was monitored at the absorbance ascribed to the oxy form at 548 nm to give the oxygen-binding affinity.The oxygen-binding equilibrium curves of PAP-CoP complex obey a Langmuir isotherm. DMF has great effects on the oxygen-binding properties of the PAP-CoP complex. The oxygen-binding affinity of PAP-CoP complex in the solid state is higher than that in DMF solution. With decreasing temperature, the oxygen-binding affinity of the PAP-CoP complex increases.     

Synthesis and Crystal Structure ofa Bipy Bridged Binuclear Cu^Ⅱ Complex Containing Aminomethanesulfonic Acid [Cu2（Sams）2（Bipy）（H2O）2]·（H2O）

The title complex [Cu2（Sams）2（H2O）2（bipy）]·（H2O） 1 （H2Sams = N-（2-hydroxybenzy） aminomethanesulfonic acid, bipy = 4,4′-bipyridine） has been synthesized by the reaction of Cu- （CH3COO）2·H2O, nESams and 4,4′-bipyridine in aqueous methanol. It was characterized by IR, elemental analysis, thermogravimetric analysis （TGA） and X-ray diffraction analysis. Complex 1 crystallizes in monoclinic, space group P21/n with a= 10.9533（17）, b = 8.3408（13）, c = 16.714（3） A^°, β = 101.295（4）°, V = 1494.3（4） A^°3 and Z = 2. The asymmetric unit is comprised of a tridentate Schiff base Sams^2- anionic ligand, a 4,4′-bipyddine and two coordinated water molecules, thus forming a binuclear copper（Ⅱ） complex. The coordination environment at Cu^Ⅱ center is described as a slightly distorted square pyramidal geometry. Via intermolecular hydrogen bonds C（10）-H（10）…O（3） and C（13）- H（13）…O（3）, an infinite supramolecular chain is yielded. A number of intermolecular hydrogen bonds greatly contribute to the stabilization of the solid-state structure for 1.     

（Salen）Ti（Ⅳ）-Catalyzed Asymmetric Ring-opening of meso Epoxides Using Dithiophosphorus Acid as the Nucleophile

The asymmetric ring-opening of epoxides with dithiophosphorus acids catalyzed by a （salen）Ti（Ⅳ） complex formed in situ from the reaction of Ti（OPr-i）4 and the chiral Schiff base derived from （1R,2R）-（＋）-diaminocyclohexane was realized. The resulting products were obtained with low to good enantioselectivity （up to 73% ee）.     

Synthesis, Characterization and Properties of Tri-substitute Potassium Salt of Trinitrophloroglucinol

The title complex [K3（TNPG）·（H2O）2]n was synthesized by the reaction of the aqueous solutions of trinitrophlomglucinol （TNPG） with KHCO3. The complex was characterized by elemental analysis and FTIR spectroscopy, and its single crystal structure was determined by X-ray diffraction analysis. The structural analysis demonstrates that two different coordination modes of K cations [K（1） and K（2）] are around TNPG^3- anions in complex [Ka（TNPG）·（H2O）2]n, where the coordination numbers are eight. All K atoms coordinate with O atoms of phenolic hydroxyl group and nitro-group simultaneously. The thermolysis of the [Ka（TNPG） · （H2O）2]n has been investigated by using differential scanning calorimetry （DSC） and thermogravimetry-derivative thermogravimetry （TG-DTG） at a heating rate of 10 ℃/min. The thermal decomposition processes of the title complex were comprised of one endothermic dehydration stage and one exothermic decomposition stage in 270-320℃, and the final decomposition residue contained KNC. Impact and friction sensitivity results of the complex revealed its sensitive nature towards mechanical stimuli. The experiments verified that the complex has some characteristics of explosive.     

Synthesis,Crystal Structure and Cytotoxic Activity of a Novel Nickel（Ⅱ） Complex with Schiff Base Derived from Salicylhydrazide

A novel Schiff base complex with π-conjugated system, [Ni（L1）2（py）2] 1 （L1 =（E）-N′-（2,4-dichlorobenzylidene）-2-oxidobenzohydraizide）, was synthesized and characterized by elemental analysis and single-crystal X-ray determination. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 12.8286（10）, b = 16.3573（13）, c = 19.0206（14） A, β = 108.2920（10）°, V = 3789.6（5）A^3, Z = 4, Mr = 833.17, Dc = 1.460 g/cm^3,/t = 0.843 mm^-1, F（000） = 1704, the final R = 0.0537 and wR = 0.0640 for 3836 observed reflections with I 〉 2σ（I）. In the molecular structure of 1, the Ni^Ⅱ atoms are six-coordinated by two N and two O atoms from two Schiff base ligands （LI） and two N atoms from two pyridine solvent molecules to form a distorted octahedral geometry. The cytotoxic activities of complex 1 have been experimentally studied against a human HeLa cell in vitro.     

Novel Isatin-Schiff Base Cu （Ⅱ） and Ni（Ⅱ） Complexes. X-ray Crystal Structure of Bis[3-（4-hexylphenylimino）-1H-indol-2（3H）-one]- dichlorocopper（Ⅱ） Complex

Schiff base ligand （HL） derived from 4-hexylaniline with isatin （1H-indole-2,3-dione） and its complexes with Cu（Ⅱ）, Ni（Ⅱ） were prepared and characterized by analytical, spectroscopic （IR, UV-Vis, Mass） techniques, electrical conductivity, magnetic and thermal measurements. The crystal and molecular structure of [Cu（HL）2Cl2] was determined by a single-crystal X-ray diffraction study. The molecular structure of the title compound has an inversion center on the Cu atom.     

Synthesis,Crystal Structure and Antimicrobial Activity of a Novel Ni（Ⅱ） Complex

A new nickel（Ⅱ） complex, C34H38N8NiO4, has been prepared and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group P21/c with a = 11.715（5）, b = 12.328（5）, c =11.113（5）A, β= 92.589（5）°, Z = 2, Dc = 1.411 g/cm^3,μ = 0.658 mml, the final R = 0.0427 and wR = 0.1099 for 2229 observed reflections with I 〉 2σ（I）. The complex is a centrosymmetric plane in which nickel（Ⅱ） is coordinated in a regular octahedron to the ligand phenytoin through the nitrogen atoms of ethylenediamine, imine and amine. The complex was valued for its antimicrobial activity against bacterial strands using the agar diffusion method, and found to be active against the four test bacterial organisms. Preliminary screening for antimicrobial activities showed that the title complex is quite active against standard strains of Salmonella species, Staphylococcus aureus, Bacillus pumilus and Eschierichia coli.     

Structural Studies and Photoluminescence of a Novel Mercury（Ⅱ） Complex Based on a Tris[4-（1-pyrazolyl）-phenyl]amine

A novel iodine-bridged mercury（Ⅱ） complex [Hg（L）（μ-I）（I）]2 was isolated by a reaction between HgI2 and the organic ligand tris[4-（1-pyrazolyl）phenyl]amine L, and the complex and ligand were both characterized by FT-IR spectroscopy, ^1H NMR and elemental analysis. The complex crystallizes in monoclinic space group P21/c with a = 9.579（5）, b = 27.331 （5）, c = 11.268（5） А, β= 105.624（5）°, Z = 2, Dc = 2.099 g·cm^-3 and μ= 7.620 mm^-1. The title complex C54H42Hg2I4N14 is a diplex bridged dinuclear complex consisting of two Hg（Ⅱ） ions, two ligands, two bridging I-anions, and two terminal I-anions. Universal hydrogen bonds in the complex with the partners of neighboring molecule have generated a supramolecular arrangement. Solid-state emission of the ligand and its complex have been investigated at room temperature.     

Design and Synthesis of a Selective Chemosensor for Zn^2＋

A hydroxyl substituted phenolic Schiff base 1, used as sensor for detection of Zn^2＋, was synthesized and investigated. It was found that a strong fluorescence emission was observed when 1 bound to Zn^2＋ in acetonitrile, whereas no fluorescence emission was detected when 1 bound to other metal ions （Fe^2＋, Co^2＋, Ni^2＋, Cu^2＋, Cd^2＋, Hg^2＋, Mg^2＋, Pb^2＋, Ca^2＋, Ba^2＋, Sr^2＋） except for Mg^2＋, for which a weak fluorescence emission was detected in the same condition. Competition experiment showed that no obvious interference was observed in its fluorescence while 1 performed the titration with Zn^2＋ in the different mixtures of metal ions. To understand the site where Zn^2＋ coordinated to the ligand and the mechanism of binding, three other hydroxyl substituted phenolic Schiff bases 2-4 were synthesized and their binding reactions with Zn^2＋were also investigated.     

Synthesis and catalytic activity of Ln (III) complexes with an unsymmetrical Schiff base including multi“非汉字符号” C=N—groups

Complexes with the unsymmetrical Schiff base can be used effectively as the stimulated metal protein and catalyst with higher activity. In order to obtain an unsymmetrical bis-Schiff base, Elder[1] suggested that the nickel bis-Schiff base complex was prepared firstly, then the corre-sponding unsymmetrical bis-Schiff base was synthesized by stripping the ligand from this com-plex with dimethylglyoxime. The resulting product with an additional —NH2 group may be con-densed with another aldehy…     

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED GLUTAMIC ACID SCHIFF BASE COMPLEX OF Mn（ Ⅱ ） IN AEROBIC OXIDATION OF CYCLOHEXENE

The polystyrene supported glutamic acid Schiff base complex of Mn （ Ⅱ ） （PS-Sal-Glue-Mn） was prepared with chloromethylated styrene polymer beads, 2,4-dihydroxybenzaldehyde, L-glutamic acid and manganese （ Ⅱ ） acetate tetrahyrate. The polymeric ligand and the complex were characterized by FT-IR, small area X-ray photoelectron spectroscopy （XPS） and 1CP-AES. In the presence of the manganese complex, cyclohexene （1） was effectively oxidized by molecular oxygen without reductant. The major products of the reaction were 2-cyclohexen-l-ol （2）, 2-cyclohexen-l-one （3） and 2-cyclohexen-1- hydroperoxide （4）, which was different with typical oxidation of cyclohexene. The influence of reaction temperature and additive for oxidation had been studied. The selectivity of 2-cyclohexen-1-hydroperoxide varied with reaction time and different additives. The mechanism of cyclohexene oxidation had also been discussed.