Yong-Jun Han

Synthesis, Structures, and Antimicrobial Activity of Schiff Base Zinc Complexes with Thiocyanate and Iodide

The Schiff base N, N-dimethyl-N′-(1-pyridin-2-ylethylidene)-ethane-1,2-diamine (L) derived from 2-acetylpyridine and N, N-dimethylethane-1,2-diamine, and its zinc(II) complexes: [ZnL(NCS)2] and [ZnLI2], have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The Schiff base coordinates to the Zn atom through the three N atoms. Each Zn atom adopts a trigonal-bipyramidal coordination. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

Synthesis, structure, and antimicrobial activity of a cadmium(II) complex derived from N,N′-bis(5-chlorosalicylidene)propane-1,3-diamine

The Schiff base, N,N′-bis(5-chlorosalicylidene)propane-1,3-diamine (H2L) derived from 5-chlorosalicylaldehyde and propane-1,3-diamine, and its cadmium(II) complex, bis(μ2-acetato)bis(μ2-N,N′-bis(5-chlorosalicylidene)-1,3-propanediamine)tricadmium(II) Cd[Cd(CH3COO)L]2 (I), have been prepared and characterized by elemental analyses, IR, and single-crystal X-ray diffraction analysis. The crystal of H2L is monoclinic: space group P21/n, a = 11.252(4), b = 8.972(3), c = 16.981(6) Å, β = 96.005(4)°, V = 1705.0(10) Å3, Z = 4. The crystal of complex I is monoclinic: space group P21/c, a = 11.056(1), b = 22.284(2), c = 8.398(1) Å, β = 91.779(1)°, V = 2068.0(3) Å3, Z = 2. Complex I is a centrosymmetric trinuclear cadmium(II) complex. The deprotonated Schiff base ligand coordinates to the Cd atoms through the phenolate O and imine N atoms. The effect of the Schiff base ligand and the complex on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.

Synthesis, structures, and antimicrobial activity of nickel(II) and Zinc(II) complexes with 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol

The Schiff base 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol (MMP) derived from 4-methoxysalicylaldehyde and N-methylpropane-1,3-diamine and its nickel(II) and zinc(II) complexes [Ni(MMP)2(NCS)2] (I) and [ZnCl2(MMP)] (II), have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P21/c, a = 9.0488(8), b = 12.7768(12), c = 12.9232(11) Å, β = 101.927(5)°, V = 1461.9(2) Å3, Z = 2. The crystal of II is orthorhombic: space group Pbca, a = 11.6991(7), b = 13.2839(8), c = 20.4451(12) Å, V = 3177.4(3) Å3, Z = 8. The Schiff base coordinates to the metal atoms through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

Synthesis, Structures, and Antimicrobial Activity of Zinc and Copper Complexes Derived From N-isopropyl-N′-(1-pyridin-2-ylethylidene)ethane-1,2-diamine

The Schiff base N-isopropyl-N′-(1-pyridin-2-ylethylidene) ethane-1,2-diamine (L) derived from 2-acetylpyridine and N-isopropylethane-1,2-diamine, and its mononuclear zinc(II) and polymeric copper(II) complexes, [ZnL(NCS)2] and [CuL(μ 2-NCS)] n ·nBF4, have been prepared and characterized by elemental analyses, IR, and single-crystal X-ray crystallographic determination. The Schiff base coordinates to the metal atoms through the three N atoms. The Zn atom in [ZnL(NCS)2] adopts a trigonal-bipyramidal coordination, and the Cu atom in [CuL(μ 2-NCS)] n ·nBF4 adopts a square-pyramidal coordination. The effect of the complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

N'-(3-Bromo-5-chloro-2-hydroxy-benzyl-idene)-4-hydr-oxybenzohydrazide.

The molecule of the title compound, C14H10BrClN2O3, is planar [dihedral angle between the aromatic rings = 3.0 (2)°] and shows a trans configuration with respect to the C=N double bond. The crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds and an intramolecular O—H⋯N interaction also occurs.

Bis{2-[3-(dimethyl­ammonio)­propyl­imino­methyl-κN]-6-meth­oxy­phenolato-κO1}bis­(thio­cyanato-κN)nickel(II)

The asymmetric unit of the title complex, [Ni(NCS)2(C13H20N2O2)2], consists of two half-molecules, both of which are completed by crystallographic inversion symmetry (Ni2+ site symmetry = in both cases). Both metal ions are six-coordinated in distorted trans-NiO2N4 geometries arising from two N,O-bidentate Schiff base ligands and two N-bonded thiocyanate ions. The molecular conformations are reinforced by two intramolecular N—H⋯O hydrogen bonds.

{N,N-Dimethyl-N′-[1-(2-pyrid­yl)ethyl­idene]propane-1,3-diamine}bis(thio­cyanato-κN)­copper(II)

In the title complex, [Cu(NCS)2(C12H19N3)], the CuII atom is five-coordinated in a square-pyramidal geometry defined by one pyridine N, one imine N, and one amine N atom of the tridentate Schiff base ligand and two N-bonded thiocyanate ions (one of the latter occupying the apical site). The three bridging C atoms and the two terminal C atoms of the Schiff base are disordered over two sets of sites, with occupancies of 0.465 (2) and 0.535 (2).

Synthesis, Structures, and Antimicrobial Activity of Schiff Base Cobalt Complexes [Co(HL1)2(N3)2]·H2O and [CoL2 2]·ClO4

The new Schiff bases 4-bromo-2-[(3-diethylaminopropylimino) methyl]phenol (HL1) and 2-methoxy-6-[(2-phenylaminoethy limino) methyl]phenol (HL2) derived from 5-bromosalicylaldehyde with N,N- diethylpropane -1,3- diamine and 3- methoxysalicylaldehyde with N-phenylethane-1,2-diamine, respectively, and their cobalt complexes, [Co(HL1)2(N3)2]·H2O and [CoL2 2]·ClO4, have been prepared and characterized by elemental analyses, infrared, and single crystal X-ray crystallographic determination. The HL1 coordinates to the Co atom through the phenolic O and imino N atoms with a zwitterionic form, while the HL2 coordinates to the Co atom through the phenolic O, imino N, and amino N atoms with a deprotonated form. Each Co atom in the complexes adopts an octahedral coordination. The effect of the Schiff bases and the complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

(2,2′-Bipyridine-κ2N,N′){N-[2-oxido-5-(phenyl­diazen­yl)benzyl­idene-κO]glycinato-κ2N,O}copper(II)

In the title compound, [Cu(C15H11N3O3)(C10H8N2)], the CuII atom is five-coordinated in a distorted square-pyramidal CuN3O2 geometry. The basal positions are occupied by three donor atoms from the tridentate Schiff base ligand and by one N atom from the 2,2′-bipyridine ligand. The axial position is occupied by the other N atom of the 2,2′-bipyridine ligand. The crystal structure is consolidated by weak C—H⋯O hydrogen bonds. In addition, π–π interactions between adjacent pyridine rings (centroid–centroid distances = 3.238 and 3.313 Å) may also stabilize the crystal packing.

Microstructure and Properties of ZL101 Alloy Affected by Substrate Movement Speed of a Novel Semisolid Continuous Micro Fused-Casting for Metal Process

A novel semisolid continuous Micro Fused-Casting additive manufacturing technology for producing a ZL101 alloy strip was developed, Micro Fused-Casting means that the semisolid metal slurry was pressed out from the outlet of bottom of crucible to the movable plate. The degree of sub-cooling was easily provided by movement of substrate in the micro fused-casting area. Under the aid of 3D manufacturing software, the ZL101 alloy strip was solidified and formed layer by layer. The microstructure and properties of ZL101 semisolid slurry were improved by the cooling conditions. The results showed that the ZL101 alloy strip samples fabricated by Micro Fused-Casting had uniform structures and good performances with the substrate movement speed at 20 mm/s and the temperature at 590 °C, the ultimate tensile strength and elongation of the ZL101 alloy strip reached 242.59 MPa and 7.71%, while the average Vickers hardness was 82.55 HV.