Synthesis and properties of Cu(II) and Pd(ii) complexes with chiral bis-α-sulfanyl oxymes, the derivatives of natural monoterpene, α-pinene

Coordination compounds Cu-2(H2L1)Cl-4 (I), Pd-2(H2L1)Cl-4 (II), Cu-2(H2L2)Cl-4 (III), and Pd-2(H2L2) Cl-4 (IV) with chiral bis-alpha-sulfanyloximes, the derivatives of the monoterpenoid (-)-alpha-pinene, were obtained. The complexes I and III are paramagnetic (mu(eff) = 2.45 and 2.67 mu(B), respectively), II and IV are diamagnetic. According to IR spectroscopy, in the compounds I-IV the nearest environment of Cu and Pd atoms includes N, S, and Cl atoms. The values of mu(eff) and parameters of ESR spectra of the solid phase and solutions of I and III show a binuclear structure of the Cu(II) complexes. Parameters of the H-1 and C-13 NMR spectra of compounds II and IV indicate the formation of binuclear Pd(II) complexes of C (2) symmetry and the closure of fivemembered chelate rings PdNSC2. The PdCl2 fragments are in transoid position. H2L1 and H2L2 are tetradentate bridging chelating ligands.