Dinuclear copper(II) complexes with bridging oximato group: Synthesis, crystal structure and solvatochromism property

Abstract

The synthesis, structure, and solvatochromism properties of two new complexes with empirical formula [Cu2L2]X2, are described, where HL stands for 2-(N,N-diisopropyl-2-aminoethyl)imino-3-butanone oximato and X is perchlorate or tetraphenylborate anion. The complexes were characterized by elemental analyses, molar conductance and spectral studies. The binuclear complex [Cu2L2](BPh4)2 was analyzed by X-ray crystallography. In complexes the copper centers are bridged through the oximato NO groups forming a dimer containing a crystallographic twofold symmetry axis. The complexes are solvatochromic and their solvatochromism were investigated by visible spectroscopy. The solvent-dependent absorption maxima, λmax, was analyzed using stepwise multiple linear regression (SMLR) method to find the best model explaining the observed positive solvatochromism. The analysis demonstrated that among different solvent parameters, donor number (DN) is a dominant factor responsible for the shift in the d-d absorption band of the complexes to the higher wavelength with increasing its values.