Optically active co-ordination compounds. Part 40. Mixed complexes of platinum(II) with L-proline and other α-amino-acids

Abstract

Mixed complexes of the type trans-[Pt(proO)A] are described (pro =L-prolinate; A = the anion of sarcosine or of the L enantiomers of alanine, serine, valine, or proline). The amino-acidate ligands are mutually trans and are bound to the platinum ion through oxygen and nitrogen. The complexes have been characterized by chemical studies, analyses, and spectra (electronic, c.d., o.r.d., ¹H n.m.r., and i.r.). The complex trans-[Pt(proO)(sarO)] has been separated into its diastereoisomeric forms, i.e. trans-[Pt(S-proO)(S-sarO)] and trans-[Pt(S-proO)(R-sarO)], where S and R denote the configurations at the asymmetric nitrogen centres. The rates of inversion (k_inv.) and of deuteriation (k_D) at the asymmetric nitrogen centres of sarcosine have been compared, and k_Dk_inv.