Syntheses, spectroscopic, structural, fluorescent and thermal properties of bis(saccharinato)copper(II) complexes with two bis(pyridylamine) ligands

Abstract

Two new copper(II) complexes of saccharinate (sac) with bis(2-pyridylmethyl)amine (bpma) and N,N'-bis[1-(pyridin-2-yl)ethylidene]ethane-1,2-diamine (bapen), [Cu(bpma)(sac)2]center dot H2O (1) and [Cu(bapen)(sac)2] (2), were synthesized and characterized by elemental analysis, TG-DTA, X-ray diffraction, and UV/Vis and IR spectroscopy, respectively. In 1, the copper(II) ion is coordinated by two N-bonded sac ligands, and three nitrogen atoms of bpma, in a distorted square-pyramidal coordination arrangement, whereas the arrangement around the copper ion in 2 is a distorted octahedron with two N-coordinated sac ligands and a tetradentate bapen ligand. In addition to hydrogen bonding involving the water molecule in 1, the mononuclear species of 1 and 2 arc further connected by weak intermolecular C-H center dot center dot center dot pi and C-H center dot center dot center dot O interactions to form a three-dimensional network. Both complexes are luminescent at room temperature and their emissions seem to be due to ligand-based it pi-pi* transitions.