Synthesis and characterization of a cobalt(III) complex with 1-(D-3-mercapto-2-methylpropionyl)-L-proline

The reaction of CoCl2 with 1-(D-3-mercapto-2-methylpropionyl)-L-proline (L or captopril) yields a new nanocrystalline complex with general formula [Co L2(OH)](2). The complex has been characterised with infrared (IR) and ultra -violet visible (UV-vis) spectroscopies, magnetic measurements, X-ray photo electron spectroscopy (XPS), and wide angle X-ray scattering (WAXS). XPS an alyses isa valuable tool for studying the chemical composition and the chem ical state of elements at the surface of solids whereas WAXS provides infor mation on the short range order. A model is proposed for the binding of the complex and its structure: the Co(III) ion is bonded with a pseudo-octahed ral configuration. Captopril molecules are coordinated via mercapto group a nd amidic C=O group to Co(III) ions: two S atoms are bridging bonded betwee n two Co(III) ions. The OH- ion completes the coordination around the Co(II I). (C) 2000 Elsevier Science B.V. All rights reserved.