Nickel(II) and copper(II) complexes with chiral bis-α-thiooxime, the derivative of natural terpenoid (+)-3-carene:: Synthesis and structures

Chiral bis-alpha-thiooxime (H2L1), the derivative of the natural monoterpenoid (+)-3-carene, was synthesized and used to prepare paramagnetic complexes of the composition M(H2L1)Cl-2 (M=Ni, Cu). The crystal structures of [Ni(H2L1)Cl-2] (I) and [Cu(H2L1)Cl-2] (II) were determined by X-ray diffraction analysis. Crystals I and II consist of mononuclear acentric molecules. The Ni2+ ion in a molecule of complex I coordinates two N atoms and two S atoms of a tetradentate chelating ligand (the H2L1 molecule) and two Cl atoms. The NiCl2N2S2 coordination core forms octahedron compressed along the apical N atoms. In a molecule of complex II, the Cu2+ ion coordinates two S atoms and the N atom of a tridentate chelating H2L1 ligand and two Cl atoms. The CuCl2NS2 coordination core forms a trigonal bipyramid.