Structure of the copper(II) perchlorate complex with Schiff base ligand containing pyridine N-oxide fragments and propylene bridges: Solvatochromic effect

摘要

The copper (II) perchlorate complexes with Schiff base ligands were investigated by X-ray single crystal analysis, electron spectroscopy, infrared and electron paramagnetic spectroscopy. The Schiff bases were obtained as condensation products of 2-pyridinecarboxaldehyde N-oxide with dipropylenetriamine (L-1) and triethylenetetramine (L), respectively. The structure of the complex [CuL2](ClO4)(2) was solved. In the structure, the ligand exists in the form of aliphatic polyamine containing two Schiff bases in contrary to the free form of this ligand with one pyrimidine ring and one Schiff base. Electronic spectra of the copper (II) perchlorate complexes of both ligands in different solvents were measured including time dependences. Vivid solvatochromic effect was observed for the complexes of both ligands. It was suggested that similar solvents cause similar equilibrium in the system and at least two different ways of isomerisation of the ligand during complexation exist. (c) 2005 Elsevier Ltd. All rights reserved.