Synthesis, Characterization and Crystal Structures of Fluoro-Substituted Aroylhydrazones with Antimicrobial Activity.

A series of five new fluoro-substituted aroylhydrazones were prepared and structurally characterized by elemental analysis, IR, UV-Vis and 1H NMR spectroscopy, as well as single crystal X-ray diffraction. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. The biological assay indicated that the presence of the electron-withdrawing groups in the aroylhydrazones improved their antimicrobial activities.

Synthesis, Characterization, Crystal Structures, and Urease Inhibition of Copper(II) and Zinc(II) Complexes Derived from Benzohydrazones.

A new copper(II) complex [Cu(L1)(NCS)(CH3OH)] (1) and a new zinc(II) complex [ZnCl2(HL2)]·CH3OH (2), derived from 4-bromo-N'-(pyridin-2-ylmethylene)benzohydrazide (HL1) and 4-methoxy-N'-(pyridin-2-ylmethylene)benzohydrazide (HL2), were prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction. The hydrazone HL1 coordinates to the Cu atom in enolate form, while the hydrazone HL2 coordinates to the Zn atom in carbonyl form. Single crystal structural analyses indicate that the hydrazones coordinate to the metal atoms through the pyridine N, imino N, and enolate/carbonyl O atoms. The Cu atom in complex 1 is in square pyramidal coordination, and the Zn atom in complex 2 is in trigonal-bipyramidal coordination. The inhibitory effects of the complexes on Jack bean urease were studied, which show that the copper complex has strong activity on urease.

Cotemplating Assembly and Structural Variation of Three-Dimensional Open-Framework Sulfides.

Open-framework sulfides (H3O)KCu6Ge2S8 (1) and (H3O)RbCu6Ge2S8 (2) were prepared by a cotemplating strategy. This shows that alkali-metal and protonated water cations act as cotemplates to direct the three-dimensional open-framework sulfides. These templates direct two types of one-dimensional channels that arrange parallelly, and different types of templates reside in different types of channels. By introduction of the Cs cation into the synthetic systems of 1 and 2, (H3O)K0.6Cs0.4Cu6Ge2S8 (3) and (H3O)Rb0.75Cs0.25Cu6Ge2S8 (4) were obtained. Compound 3 has a different anionic framework from those of 1 and 2, while 4 is isostructural with 1 and 2.

Synthesis, crystal structures and insulin-like activity of three new oxidovanadium(V) complexes with aroylhydrazone ligand.

Three new oxidovanadium(V) complexes were designed, synthesized and characterized by C, H, N elemental analysis, single crystal X-ray diffraction，UV/Vis and IR spectra. Complex 1: [VOL1X] (H2L1 = (E)-N'-(2-hydroxybenzylidene)-3-methbenzohydrazide, HX = ethylmaltol = 2-ethyl-3-hydroxy-4-pyrone), Complex 2: [VOL2(CH3O)(CH3OH)], (H2L2 = C16H16N2O4 = (E)-N'-(2-hydroxybenzylidene)-3,5-dimethoxybenzohydrazide, CH3OH = methanol), Complex 3: [VOL3X] (H2L3 = (E)-N'-(3-ethoxy-2-hydroxybenzylidene)-3,5-dimethoxybenzohydrazide). The insulin-like activity of the three complexes was tested. Both normal and streptozotocin (STZ)-diabetic mice were administered intragastrically for two weeks. It was found that the complexes at doses of 10.0 and 5.0 mg V·kg-1 can significantly decrease the blood glucose level in STZ-diabetic mice, and the blood glucose level in the treated normal mice was not altered. The lesions of kidney and liver caused by diabetes have varying degrees of improvement.

Free radical scavenging activity and neuroprotective potentials of D138, one Cu(II)/Zn(II) Schiff-base complex derived from N,N'-bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine.

There is increasing evidence that free radicals play an important role in neuronal damages induced by diabetes mellitus or cerebral ischemia insults. Antioxidants with free radical scavenging activities have been shown to be beneficial and neuroprotective for these pathological conditions. Here, we report free radical scavenging activity and neuroprotective potential of D138, one copper(II)/zinc(II) Schiff-base complex derived from N,N'-2(2-hydroxynaphthylmethylidene)-1,3-propanediamine. The data from three in vitro assays, 2,2-diphenyl-1-picrylhydrazyl assay, nitro blue tetrazolium assay and hydroxyl radical scavenging assay, indicated that D138 presented a potent free radical scavenging activity. The neuroprotective and antioxidative effects of D138 were further evaluated in vivo using bilateral common carotid artery occlusion (BCCAO) mouse model and streptozotocin (STZ) diabetic mouse model. Our results indicated that treatment of D138 significantly ameliorated the hippocampal neuronal damage and the oxidative stress levels in these animal models. Moreover, D138 also reversed the behavioral deficiencies induced by BCCAO or STZ, as assessed by Y-maze test and fear conditioning test. In conclusion, all these findings support that D138 exerts free radical scavenging and neuroprotective activities and has the potentials to be a potent therapeutic candidate for brain oxidative damage induced by cerebral ischemia or diabetes mellitus.

Synthesis and crystal structures of ethanol-coordinated molybdenum(VI) oxo complexes with tridentate hydrazone ligands.

Reaction of [MoO2(acac)2] (where acac = acetylacetonate) with two similar hydrazone ligands in ethanol yielded two ethanol-coordinated mononuclear molybdenum(VI) oxo complexes with general formula [MoO2L(EtOH)], where L = L1 = (N'-(3,5-dibromo-2-hydroxybenzylidene)-4-nitrobenzohydrazide (H2L1), and L = L2 = (N'-(3,5-dibromo-2-hydroxybenzylidene)-2-fluorobenzohydrazide (H2L2). Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method. All of the investigated compounds were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligands coordinate to the MoO2 cores through enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination. Thermal stability of the complexes has also been studied.

Synthesis, biological evaluation, and molecular docking studies of 2,5-substituted-1,4-benzoquinone as novel urease inhibitors.

A series of 2,5-substituted-1,4-benzoquinone (1-6) were prepared and structurally characterized by elemental analysis, IR spectra, (1)H and (13)C NMR spectra, and single crystal X-ray determination. The urease inhibitory activities of the compounds against H. pylori urease were studied. Among the compounds, 2,5-bis(2-morpholin-4-ylethylamino)-[1,4]benzoquinone (2) shows the most effective activity with IC(50) value of 27.30 ± 2.17 µM. Docking simulation was performed to insert compound 2 into the crystal structure of H. pylori urease at the active site to determine the probable binding mode. As a result, compound 2 may be used as a potential urease inhibitor.

The unprecedented preparation of dinuclear zinc(II) complexes from 4-halido-2-[(3-cyclohexylaminopropylimino)methyl]phenol.

Three new centrosymmetric trinuclear nickel(II) and manganese(II) complexes, Ni[Ni(CH(3)COO)(CPA)](2) (1), Ni[Ni(CH(3)COO)(BPA)](2) (2), Mn[Mn(CH(3)COO)(BPA)](2) (3), where H(2)CPA = N,N'-bis(5-chlorosalicylidene)-1,3-propanediamine, H(2)BPA = N,N'-bis(5-bromosalicylidene)-1,3-propanediamine, and two new centrosymmetric dinuclear zinc(II) complexes, [Zn(2)(CMP)(2)] (4) and [Zn(2)(BMP)(2)] (5), where H(2)CMP = 4-chloro-2-{[3-(5-chloro-2-hydroxybenzyl)aminopropylimino]methyl}phenol, and H(2)BMP = 4-bromo-2-{[3-(5-bromo-2-hydroxybenzyl)aminopropylimino]methyl}phenol, have been prepared from the Schiff bases derived from 5-halido-substituted salicylaldehydes with N-hexylpropane-1,3-diamine under solvothermal conditions. The complexes have been characterised by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction studies. The complexes 1, 2, and 3 crystallise in the monoclinic space group P2(1)/c with cell dimensions a = 9.347(1), b = 11.507(2), c = 18.539(2) Å, ß = 93.774(2)°, Z = 2 (for 1), a = 9.111(4), b = 12.089(6), c = 18.724(8) Å, ß = 92.117(7)°, Z = 2 (for 2), and a = 11.328(2), b = 22.468(5), c = 8.270(2) Å, ß = 93.74(3)°, Z = 2 (for 3), while complexes 4 and 5 crystallise in the triclinic space group P1, with cell dimensions a = 7.483(1), b = 9.990(2), c = 12.155(2) Å, α = 75.27(3), ß = 85.00(3), γ = 73.82(3)°, Z = 1 (for 4), and a = 7.008(1), b = 10.081(2), c = 13.095(3) Å, α = 100.62(3), ß = 95.51(3), γ = 104.03(3)°, Z = 1 (for 5). It is interesting that the mono-Schiff bases 4-chloro-2-[(3-cyclohexylaminopropylimino)methyl]phenol (HCCP) and 4-bromo-2-[(3-cyclohexylaminopropylimino)methyl]phenol (HBCP) used to prepare the nickel(II) and manganese(II) complexes were transferred to bis-Schiff bases H(2)CPA and H(2)BPA in the complexes 1, 2, and 3, while the mono-Schiff bases HCCP and HBCP used to prepare the zinc(II) complexes were transferred to novel ligands H(2)CMP and H(2)BMP, bearing the unexpected, newly formed carbon-nitrogen single bond.

Antihyperglycemic and neuroprotective effects of one novel Cu-Zn SOD mimetic.

Increasing evidence supports that OS plays important roles in diabetes mellitus and cerebral ischemia. This suggests that recovering an impaired endogenous superoxide dismutase (SOD) enzyme system induced by OS with a mimetic would be beneficial and protective for these diseases. In present study, one nonpeptidyl small molecular weight compound (D34) was synthesized. Its SOD mimetic activity and the potential therapeutic actions were also evaluated both in vivo and in vitro. The in vitro nitro blue tetrazolium (NBT) assay indicated that D34 presents an SOD mimetic activity. D34 (20µmol/kg) exhibited significant antihyperglycemic activity in alloxan-diabetic mice. D34 could also ameliorate the cerebral neuronal death in hippocampus of global cerebral ischemia mice. Furthermore, the D34 treatment significantly decreased malondialdehyde (MDA) contents and increased SOD activities in brains or livers of diabetes mice or cerebral ischemic mice. In conclusion, these preliminary findings support that D34 exhibits SOD mimetic activity and possesses significant antihyperglycemic and neuroprotective effects.

Synthesis, structures, and urease inhibitory activities of three copper(II) and zinc(II) complexes with 2-{[2-(2-hydroxyethylamino)ethylimino]methyl}-4-nitrophenol.

In order to explore novel urease inhibitors, three new mononuclear complexes of Cu(II) and Zn(II) with Schiff base 2-{[2-(2-hydroxyethylamino)ethylimino]methyl}-4-nitrophenol have been prepared and structurally characterized by X-ray crystallography. Among the three complexes, two Cu(II) complexes show strong urease inhibitory activities with the IC(50) values being much lower than that of the acetohydroxamic acid, while the Zn(II) complex shows no activity at the concentration of 100 microM.

2,2'-(Quinoxaline-2,3-di-yl)diphenol dimethyl-formamide solvate.

In the title compound, C(20)H(14)N(2)O(2)·C(3)H(7)NO, the quinoxaline ring forms dihedral angles of 64.9 (2) and 30.9 (2)° with the two substituted benzene rings, which are themselves inclined at 58.4 (2)°. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, mol-ecules are linked through inter-molecular O-H⋯O hydrogen bonds.

Schiff base transition metal complexes as novel inhibitors of xanthine oxidase.

Twenty transition metal complexes with Schiff bases were evaluated for their inhibitory activities on xanthine oxidase (XO), of which 11 were newly synthesized and characterized by X-ray single crystal diffraction. It was found that 9 of the 20 complexes showed potent inhibitory activities against XO near to the standard inhibitor allopurinol. The cadmium(II) complex (8) had the most potent inhibitory activity with the IC(50) value of 2.16 microM. Relationships between the structures and the activities showed that the ligands and the metal ions influenced the inhibitory activities. The XO inhibition of the Schiff base metal complexes most probably resulted from their direct interactions with the enzymes "in the whole complex form". These results demonstrated that the Schiff base transition metal complexes could be potential selective XO inhibitors.

catena-Poly[[bis[mu-2,4-dichloro-6-(2-pyridylmethyliminomethyl)phenolato]dicadmium(II)]-di-mu-thiocyanato].

The title complex, [Cd2(C13H9Cl2N2O)2(NCS)2]n, is a novel thiocyanate-bridged polynuclear cadmium(II) compound. The Cd(II) atom is six-coordinated in a distorted octahedral configuration, with one O and two N atoms of one Schiff base molecule and one terminal S atom of a bridging thiocyanate ligand defining the equatorial plane, and one terminal N atom of another bridging thiocyanate ligand and one O atom of another Schiff base molecule occupying axial positions. Adjacent inversion-related [2,4-dichloro-6-(2-pyridylmethyliminomethyl)phenolato]cadmium(II) moieties utilize bridging phenolate and thiocyanate groups to form polymeric chains running along the b axis.

Di-mu-acetato-bis{[2,4-dichloro-6-(2-pyridylmethyliminomethyl)phenolato]zinc(II)} and di-mu-thiocyanato-bis{[2,4-dichloro-6-(2-pyridylmethyliminomethyl)phenolato]copper(II)}.

The two title complexes, [Zn(2)(C(13)H(9)Cl(2)N(2)O)(2)(C(2)H(3)O(2))(2)], (I), and [Cu(2)(C(13)H(9)Cl(2)N(2)O)(2)(NCS)(2)], (II), are dinuclear Schiff base compounds. Both molecules are located on crystallographic centres of inversion. In (I), the Zn(II) atom is five-coordinated in a trigonal-bipyramidal coordination, with one imine N atom of one Schiff base and two acetate O atoms defining the basal plane, and one O atom and one pyridine N atom of the Schiff base occupying the axial positions, while in (II), the Cu(II) atom is five-coordinated in a square-pyramidal coordination, with one O and two N atoms of one Schiff base and one terminal N atom of a bridging thiocyanate ligand defining the basal plane, and one terminal S atom of another bridging thiocyanate ligand occupying the apical position. The different bridging ligands lead to the different coordinations of the complexes.

catena-Poly[[[4-bromo-2-(2-pyridylmethyliminomethyl)phenolato]zinc(II)]-mu-chloro].

The title complex, [Zn(C13H10BrN2O)Cl]n, is a chloride-bridged polynuclear zinc(II) compound. Each ZnII ion is five-coordinated in a square-pyramidal configuration, with one O and two N atoms of one Schiff base and one bridging Cl atom defining the basal plane, and another bridging Cl atom occupying the apical position. The novelty of the compound lies in the bridging by chlorine of two square-pyramidal Zn atoms, so that the bridging atom is apical for one Zn ion and basal for the other. This structural arrangement has not been observed before. The linked moieties form polymeric zigzag chains running along the a axis.

catena-Poly[[{4-bromo-2-[2-(dimethylamino)ethyliminomethyl]phenolato}copper(II)]-mu-thiocyanato].

The title complex, [Cu(C11H14BrN2O)(NCS)]n, is an interesting thiocyanate-bridged polynuclear copper(II) compound, which crystallizes with two independent molecules in the asymmetric unit. Each CuII atom is five-coordinate in a square-pyramidal configuration, with one O and two N atoms of one Schiff base ligand and one terminal N atom of a bridging thiocyanate ligand defining the basal plane, and one terminal S atom of another bridging thiocyanate ligand occupying the apical position. The {4-bromo-2-[2-(dimethylamino)ethyliminomethyl]phenolato}copper(II) units are linked by the bridging thiocyanate ligands, forming polymeric chains running along the a axis. There are weak intermolecular C-H...O and C-H...S hydrogen bonds between the chains in the crystal structure.

catena-Poly[[[2,4-dichloro-6-(pyridin-2-ylmethyliminomethyl)phenolato]copper(II)]-mu-thiocyanato].

The title complex, [Cu(C13H9Cl2N2O)(NCS)]n, is a novel thiocyanate-bridged polynuclear copper(II) compound. The CuII atom is five-coordinated in a square-pyramidal configuration, with one O and two N atoms of one Schiff base ligand and one terminal N atom of a bridging thiocyanate ligand defining the basal plane, and one terminal S atom of another bridging thiocyanate ligand occupying the axial position. The [2,4-dichloro-6-(pyridin-2-ylmethyliminomethyl)phenolato]copper(II) moieties are linked by the bridging thiocyanate ligands, forming polymeric chains running along the a axis.

Di-mu-azido-bis{[1-(2-pyridylmethyliminomethyl)-2-naphtholato]zinc(II)}.

The title compound, [Zn2(C17H13N2O)2(N3)2], is an azide-bridged dinuclear zinc(II) complex which has inversion symmetry. The ZnII atom is five-coordinated in a square-pyramidal configuration by one O and two N atoms of one Schiff base ligand [Zn-O=1.902 (2) A and Zn-N=1.938 (2) and 2.002 (2) A] and by one terminal N atom [Zn-N=1.985 (2) A] of a bridging azide ligand defining the basal plane, and by another terminal N atom of another bridging azide ligand [Zn-N=2.554 (2) A] occupying the apical position.

Dichloro{2-[2-(dimethylammonio)ethyliminomethyl]-4-nitrophenolato}zinc(II) in unsolvated and hemihydrate forms.

The two title complexes, [ZnCl2(C11H15N3O3)], (I), and [ZnCl2(C11H15N3O3)].0.5H2O, (II), are mononuclear zinc(II) compounds. In both structures, the Zn(II) atom is four-coordinated in a tetrahedral configuration by one imine N atom and one phenolate O atom of a Schiff base, and by two Cl atoms. The structure of each of the two zinc(II) complex molecules of (II) is similar to that of (I). In (I), the molecules are linked through intermolecular hydrogen bonds, forming a three-dimensional framework. In (II), the solvent water molecules are linked to the zinc(II) moieties through intermolecular O-H...O and O-H...Cl hydrogen bonds. The molecules in (II) are further linked via other intermolecular hydrogen bonds, forming a three-dimensional framework.

A novel thiocyanate-bridged dinuclear cadmium(II) complex: di-mu-thiocyanato-bis((methanol){4-nitro-2-[2-(dimethylamino)ethyliminomethyl]phenolato}cadmium(II)).

The title complex, [Cd2(C11H14N3O3)2(NCS)2(CH4O)2], is an interesting thiocyanate-bridged dinuclear cadmium(II) compound. It is located on a crystallographic inversion center. The CdII atom is six-coordinated in an octahedral configuration by one O and two N atoms of one Schiff base ligand and by the terminal N atom of a bridging thiocyanate ligand, defining the basal plane, and by the terminal S atom of another bridging thiocyanate ligand and by the O atom of a coordinated methanol molecule, occupying the axial positions. The molecules are linked through intermolecular O-HO hydrogen bonds, forming chains running along the b axis.