New Re(I) tricarbonyl-diimine complexes with N,N '-bis(substituted benzaldehyde)-1,2-diiminoethane Schiff base ligands: Synthesis, spectroscopic and electrochemical studies and crystal structures

摘要

The syntheses, structures and spectroscopic properties of tricarbonylrhenium(I) complexes with N,N'bis(2-bromo, 4-bromo, 4-chloro and 3-methoxybenzaldehyde)-1,2-diiminoethane Schiff base ligands have been investigated in this paper. Characterization of these complexes was carried out with FTIR, NMR, UV-Vis spectroscopy, elemental analysis and X-ray crystallography. The electrochemical behavior of the investigated complexes has been studied by cyclic voltammetry. The crystal structures of the 4-chloro, 4-bromo and 4-methoxy substituted complexes are stabilized by intermolecular C-H center dot center dot center dot Cl and C-H center dot center dot center dot O hydrogen bonds. The remarkable features of the 2-bromo, 4-bromo and 4-chloro substituted complexes are short intermolecular halogen-oxygen contacts. In the 4-bromo complex, short intermolecular Br center dot center dot center dot O and O center dot center dot O contacts link neighboring molecules along the 11 001 direction, which are further stabilized by short intermolecular pi center dot center dot center dot pi interactions. In 2-bromo complex, intermolecular Br center dot center dot O interactions link neighboring molecules into 1D extended chains along the 101 01 and 10 0 11 directions, forming a 20 network which is parallel to the bc-plane. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.