X-Ray Structures and Spectral Properties of 4-Coordinate Copper(II) and Palladium(II) Complexes with a Tridentate ONN-Schiff Base Ligand

Abstract

Abstract The tridentate mono-basic Schiff base N-(2-diethylaminoethyl)salicylaldimine ≙Hsal-en-NEt2 forms complexes 1 = [(sal-en-NEt2)MY] with divalent metals M (Y = halide). The preparation of three copper(II) complexes 1a (Y=Br), 1b (Y=Cl), and 1c (Y=SCN) and one palladium(II) complex 1(1 (Y=Cl) is described and the UV/VIS spectra of these complexes in methanol and chloroform are compared and discussed. The crystals of 1a · CHCl3, 1b · CHCl3, and 1d · CHCl3 are all isotypic and crystallize in the orthorhombic space group Pbca, whereas the solvent-free crystals of 1 b (and also 1 a) are monoclinic with the space group P21/c. The metal is 4-coordinate with an almost planar ONNY donor atom arrangement around the palladium and with a distorted arrangement around the copper. The crystals consist of separate non-bridged complex units and the chloroform is not coordinated.