M. A. Jalil Miah

Metal complexes of some schiff bases derived from s-benzyldithiocarbazate

Abstract New metal complexes of Schiff base ligands derived from S-benzyldithiocarbazate have been prepared and characterized by elemental analysis and magnetic and spectroscopic measurements. In neutral or slightly acidic media, the Schiff bases formed from acetone, benzophenone, acetaldehyde and benzaldehyde behave as neutral [NS] bidentate chelating agents forming both bis- and tris-chelated nickel (II) complexes of general formula, Ni[NS] 2 X 2 (X = Cl − , NCS − ) and Ni [NS] 3 X 2 (X = Cl − , Br − and NO 3 − ), respectively, which are high-spin and octahedral. The complexes, Co[NS] 3 X 2 (X = Cl − or NO 3 − ) and Cu[NS] 2 (NO 3 ) 2 were also isolated. Magnetic and spectral evidence support an octahedral structure for the cobalt(II) complexes and a square-planar structure for the copper(II) complexes. In the presence of alkali the NS Schiff bases deprotonate yielding neutral complexes, Ni[NS − ] 2 which are diamagnetic and square-planar. The diacetyl Schiff base of S-benzyldithiocarbazate behaves as a dinegatively charged quadridentate ligand forming neutral 1:1 complexes with nickel and copper(II). Magnetic and spectral data are in accord with a square-planar structure for these complexes.

Magnetic and Temperature-Sensitive Composite Polymer Particles and Adsorption Behavior of Emulsifiers and Trypsin

A combination of magnetic and temperature-responsive properties in the same polymer composites is expected to increase their potential applications in the biomedical field. Accordingly, micron-sized magnetite/polystyrene/ poly(2-dimethylaminoethyl methacrylate-ethyleneglycol dimethacrylate), which are abbreviated as Fe3O4/PS/P (DM-EGDM) composite polymer particles, were prepared by the seeded copolymerization of DM and EGDM in the presence of magnetite/polystyrene (Fe3O4/PS) particles. Fe3O4/PS/P(DM-EGDM) composite particles with magnetic properties showed a temperature-sensitive phase transition at approximately 31 °C. The adsorption behavior of the low molecular weight emulsifiers and trypsin (TR) as biomolecules were examined on Fe3O4/PS/P(DM-EGDM) composite polymer particles at different temperatures. The native conformation of TR was followed by measuring the specific activity under various adsorption conditions. The activity of the adsorbed TR on composite polymer particles was higher than those of the free TR and TR adsorbed on Fe3O4/PS particles.