Da-Hua Shi

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.

Synthesis, Crystal Structures, and Urease Inhibitory Activities of Two Isostructural Schiff Base Cadmium(II) Complexes

Two isostructural cadmium(II) complexes, [Cd(L1)(NO 3 ) 2 (H 2 O)] · CH 3 OH (1) and [Cd(L2)(NO 3 ) 2 (H 2 O)] · CH 3 OH (2), derived from the Schiff bases 4-bromo-2-[(2-piperazinylethylimino)methyl]phenol (L1) and 4-chloro-2-[(2-piperazinylethylimino)methyl]phenol (L2), respectively, were prepared and structurally characterized by X-ray diffraction. Each complex consists of a mononuclear cadmium(II) complex molecule and a methanol molecule of crystallization. The Cd atom in each complex is six-coordinated by one phenolate O, one imine N and one amine N atoms of the Schiff base ligand, two O atoms from two nitrate anions, and one water O atom, forming distorted octahedral coordination. The urease inhibitory activities of the complexes were evaluated.

Synthesis, Crystal Structures, and Biological Activity of Schiff Base Zinc(II) Complexes Derived From (2-piperidin-1-ylethyl)-(1-pyridin-2-ylethylidene)amine

Two new similar zinc(II) complexes, [ZnI2L] (1) and [Zn(NCS)2L] (2), derived from the Schiff base (2-piperidin-1-ylethyl)-(1-pyridin-2-ylethylidene)amine(L), were prepared and structurally characterized by X-ray diffraction. The Zn atom in each complex is five-coordinated by the three N atoms of the Schiff base ligand, and by two I or N atoms of the terminal iodide or thiocyanate groups, forming distorted square-pyramidal coordination. The urease inhibitory activities of the complexes and the ligand were evaluated.

Synthesis and Crystal Structures of Schiff Base Nickel(II) Complexes With Biological Activity

Two mononuclear nickel(II) complexes, [Ni(MMP)(NCS)] (1) and [Ni(PMP)(NCS)] (2), where MMP = 5-methoxy-2-[(2-morpholin-4-ylethylimino)methyl]phenolate, PMP = 5-methoxy-2-[(pyridin-2-ylmethylimino)methyl]phenolate, were prepared and structurally characterized by X-ray diffraction. The Ni atom in each complex is four-coordinated by three donor atoms of the Schiff base ligand, and by one thiocyanate N atom, forming a square planar coordination. The urease inhibitory activity of the complexes was evaluated.

Synthesis, crystal structures, and biological activity of zinc(II) complexes derived from 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol

Two new Schiff base zinc(II) complexes, [ZnBr2L] (I) and [ZnCl2L] (II), where L is 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol, were synthesized and characterized by physico-chemical methods and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P21/n a = 7.250 (2), b = 16.136 (3), c = 15.802 (3) Å, β = 90.027 (3)°, V = 1848.6 (7) Å3, Z = 4. The crystal of II is monoclinic: space group P21/n, a = 7.177 (3), b = 15.970 (4), c = 15.689 (3), β = 91.674 (3)°, V = 1797.5 (9) 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 halide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.

Synthesis, Crystal Structures, and Biological Activity of Cu(II), Mn(III), and Fe(III) Complexes Derived from N,N’-Bis(4-methoxysalicylidene)ethylenediamine

Three mononuclear copper(II), manganese(III), and iron(III) complexes, [CuL(OH2)] (1), [MnClL] (2), and [FeClL] (3), where L is the deprotonated form of N,N’-bis(4-methoxysalicylidene) ethylenediamine, were synthesized and structurally characterized by physicochemical methods and single-crystal X-ray diffraction. Each metal atom in the complexes adopts a square pyramidal coordination, with the four donor atoms of the Schiff base defining the basal plane, and with the water molecule for 1, and chloride atom for 2 and 3 occupying the apical position. The complexes were evaluated in vitro for their inhibitory activities against Jack bean urease. The copper complex showed effective inhibitory activity against the urease. A docking simulation was performed for the copper complex into the active site of the urease to investigate the probable binding conformation.

Synthesis, crystal structures, and biological activity of zinc(II) complexes derived from 2-amino-1,3,4-thiadiazole derivatives

ABSTRACT Two new similar zinc(II) complexes, [ZnCl2L12] and [ZnCl2L22], derived from the 2-amino-1,3,4-thiadiazole derivatives, were prepared and structurally characterized by X-ray diffraction. The Zn atom in each complex has a tetrahedral coordination and is coordinated by two N atoms of the ligands and two Cl atoms. The urease inhibitory activities of the complexes and the ligands were evaluated.

Synthesis, Characterization, and Crystal Structures of Copper(II) and Zinc(II) Complexes Derived From the Tridentate Schiff Bases 2-[1-(pyridin-2-ylmethylimino) ethyl]phenol and (1-pyridin-2-ylethylidene)pyridin-2- ylmethylamine

A centrosymmetric phenolate oxygen bridged dinuclear copper(II) complex [Cu2(L1)2(N3)2] (1) and a mononuclear zinc(II) complex [Zn(L2)(NCS)2] (2), where HL1 = 2-[1-(pyridin-2-ylmethylimino)ethyl]phenol and L2 = (1-pyridin-2-ylethylidene)pyridin-2-ylmethylamine, were synthesized and structurally characterized by physicochemical methods and single-crystal X-ray diffraction. The Cu atom in (1) is five-coordinated in a slightly distorted square pyramidal geometry, and the Zn atom in (2) is five-coordinated in a severely distorted square pyramidal geometry.