Synthesis,structural characterization and catalytic activity study of Mn(II), Fe(III), Ni(II), Cu(II) and Zn(II) complexes of quinoxaline-2-carboxalidine-2-amino-5-methylphenol: Crystal structure of the nickel(II) complex |
| |
Authors: | Manju Sebastian V Arun PP Robinson Annu Anna Varghese Rani Abraham E Suresh KK Mohammed Yusuff |
| |
Institution: | 1. Department of Applied Chemistry, Cochin University of Science and Technology, Cochin 682 022, Kerala, India;2. Analytical Sciences Division, Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat 364 002, India |
| |
Abstract: | Five new transition metal complexes MnL(OAc)]·H2O (1), FeLCl2] (2), NiL2]·H2O (3), CuLCl] (4) and ZnL2]·2H2O (5) have been synthesized using a tridentate Schiff base ligand, HL (quinoxaline-2-carboxalidine-2-amino-5-methylphenol) and the complexes have been characterized by physicochemical and spectroscopic techniques. The spectral analyses reveal an octahedral geometry for 3, square pyramidal structure for 2 and square planar structure for 4. Analytical and physicochemical data indicate tetrahedral structure for 1 and octahedral structure for 5. The crystallographic study reveals that NiL2]·H2O shows distorted octahedral geometry with a cis arrangement of N4O2 donor set of the bis Schiff base and exhibits a two-dimensional polymeric structure parallel to 0 1 0] plane. The complexes were screened for catalytic phenol hydroxylation reaction. Coordinatively unsaturated manganese(II), iron(III) and copper(II) complexes were found to be active catalysts. The poor catalytic activity of the nickel(II) complex is due to coordinatively saturated octahedral nature of the complex. Maximum conversion of phenol was observed for the copper(II) complex and the major product was catechol. |
| |
Keywords: | Schiff base Quinoxaline-2-carboxaldehyde 2-Amino-5-methylphenol Crystal structure Phenol hydroxylation |
本文献已被 ScienceDirect 等数据库收录! |
|