Zhong-Lu You

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.

Two lantern-like 1D polymeric Schiff base copper(I/II) complexes derived from copper(II) salts containing rarely seen [CuI(NCS)4] bridges

Two lantern-like 1D polymeric Schiff base copper(I/II) complexes containing rarely seen [CuI(NCS)4] bridges have been obtained by reaction of tridentate Schiff bases, copper(II) salts, and ammonium thiocyanate in methanol under mild condition.

Preparation and structural characterization of oxovanadium(V) complexes with Schiff bases and their inhibition studies on Helicobacter pylori urease

A series of structurally similar dinuclear oxovanadium(V) complexes, [VO2L]2 (L = L1 = 2-[(2-methylaminoethylimino)methyl]phenolate (1); L = L2 = 2-[(2-ethylaminoethylimino)methyl]phenolate (2); L = L3 = 2-[(2-isopropylaminoethylimino)methyl]phenolate (3)), has been synthesized and characterized by physico-chemical methods and single-crystal X-ray diffraction. The V in each complex is octahedral, with three donors of L and one oxo defining the equatorial plane, and with two oxos occupying the axial positions. The complexes were tested for their urease inhibitory activities. The inhibition rate (%) of 1, 2, and 3 at 100 µmol L−1 on urease are 67 ± 1, 53.5 ± 0.9, and 44 ± 1. The relationship between structures of the complexes and the urease inhibitory activities indicates that shorter terminal groups of the complexes have stronger activities against urease. Molecular docking study of the complexes with the Helicobacter pylori urease was performed.

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.

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.

Synthesis, characterization, and crystal structures of two Schiff base zinc(II) complexes with urease inhibitory activities

Two Schiff base zinc(II) complexes, [ZnBr2L1] · 2CH3OH (I) (I) and [ZnBr2L2] (II), where L1 is 4-chloro-2-[(2-piperazin-1-ylethylimino)methyl]phenol and L2 is 4-chloro-2-[(3-diethylaminopropylimino)methyl]phenol were synthesized and structurally characterized. The crystal of I is monoclinic: space group P21/c, a = 9.831(3), b = 18.680(6), c = 11.879(4) Å, β = 94.660(6)°, V = 2174.3(11) Å3, Z = 4. The crystal of II is monoclinic: space group P21/n, a = 7.2310(14), b = 16.037(3), c = 15.856(3), β = 90.01(3)°, V = 1838.7(6) Å3, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two bromide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.

Dinuclear Schiff-base copper(II) complexes with various bridging groups

Three new centrosymmetric dinuclear copper(II) complexes, [Cu2Cl2(L1)2] (1), [Cu2(μ 1,3-NCS)2(L2)2] (2), and [Cu2(μ 1,1-N3)2(L3)2] (3), where L1, L2, and L3 are the deprotonated forms of the Schiff bases 1-[(2-propylaminoethylimino)methyl]naphthalen-2-ol (HL1), 1-[(3-methylaminopropylimino)methyl]naphthalen-2-ol (HL2), and 2-[(2-isopropylaminoethylimino)methyl]phenol (HL3), respectively, have been prepared and characterized by elemental analysis, IR spectra, and single-crystal X-ray crystallography. Each Cu is coordinated by the three donors of the Schiff bases and by two bridging groups, forming a square-pyramidal geometry.

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, crystal structures, and superoxide dismutase activity of two isostructural copper(II)–zinc(II) complexes derived from N,N′-bis(4-methoxysalicylidene)cyclohexane-1,2-diamine

Two new isostructural copper(II)–zinc(II) complexes, [CuZnLBr2] (1) and [CuZnLCl2] (2) (H2L = N,N′-bis(4-methoxysalicylidene)cyclohexane-1,2-diamine), have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Both complexes crystallize in the P-1 space group. The Cu in each complex is four-coordinate square planar with two imines and two phenolates of L. The Zn in each complex is four-coordinate tetrahedral with two phenolates of L and two halides (Br for 1 and Cl for 2). The superoxide dismutase (SOD) activity of the complexes indicates that both complexes are rudimentary models for SOD.

Synthesis, Crystal Structures, and Preliminary Antibacterial Activities of Zinc(II) Complexes With a Tetradentate Schiff Base N,N′-Bis(1-pyridin-2-ylethylidene)propane-1,2- diamine

Two new mononuclear Schiff base zinc(II) complexes with the formula [ZnXL]·BF4 [X = Cl for (1) and X = Br for (2); L = N,N′-bis(1-pyridin-2-ylethylidene)propane-1,2-diamine] have been prepared. The complexes have been characterized by physicochemical methods and single-crystal X-ray determination. Each compound contains a mononuclear zinc(II) complex cation and a disordered fluoroborate anion. The zinc(II) atoms in both complexes are five-coordinated by the four N atoms of L, and by one halide atom, forming a square-pyramidal coordination. The Schiff base ligand and the zinc(II) complexes showed potent antibacterial activities.