59Co-NMR-spektroskopische Untersuchungen an [Co(NO)2X(PZ3)]-Komplexen / 59Co NMR Spectroscopic Investigations of [Co (NO) 2X (PZ3)] Complexes

Abstract

59Co-nmr-spectroscopic investigations of solutions of the complexes [Co (NO)2X(PZ3)]* in CH2Cl lead to relations between the chemical shift τo and bonding parameters of the Co-X-bond and the Co-PZ3-bond, respectively. With decreasing chemical shift, covalency of the Co-X-bond is increasing in the order Cl<Br<J. Regarding the PZ3 ligands, τCo is a measure of the π-acceptor ability of PZ3, which increases in the order PPh3 ∼ PPh2Z ∼ PPhCl2 < alkylphosphine ∼ phenylalkylphosphine ∼ phosphines containing NR2-groups < phosphines containing OR-groups. The different π-accetor abilities are explained by varying Z-P-interaction.