Crystal structures of two copper(II) complexes with <Emphasis Type="Italic">N,N</Emphasis>-diethylbenzhydrazide

The copper(II) complexes with N,N-diethylbenzhydrazide, Cu(C₆H₅CONHN(C₂H₅)₂)]Cl₂ (I) and Cu(C₆H₅CONN(C₂H₅)₂)₂ (II), have been studied by X-ray diffraction analysis. In the both compounds, the reactant acts as a bidentate (O, N(2)) ligand, forming five-membered chelate rings with copper. In cationic complex I, the O→Cu and N→Cu bond lengths are 1.954(2) and 2.070(3) Å, respectively, and the O(1)CuN(2) chelate angle is 81.89(10°. The Cl^? ions are in the coordination sphere of copper (Cu-Cl, 2.1974(11) and 2.2178(10) Å). The chelate ring has an envelope conformation with the copper atom in the flap position. The coordination polyhedron of the copper atom is a strongly distorted tetrahedron. Neutral complex II is an inner complex salt. The reactant forms with copper two planar chelate rings. The Cu-O and N→Cu bond lengths are 1.8901(9) and 2.0175(11) Å, respectively, and the O(1)CuN(2) chelate cycle is 83.70(4)°. Complex II is planar, and the coordination polygon of the copper atom is a parallelogram. The thermal stability of complexes I and II has been studied.