Electrochemical characterization of a new vanadium penicillamine-ester complex
摘要:
The synthesis and isolation of VO(Pen-OCH3)2 (Pen-OCH3 = the anion of the carboxylate ester of penicillamine) is reported. This is the first report of the isolation of a vanadyl complex with penicillamine ligands. Based on IR data, the structure is proposed to be similar to that of VO(Cys-OCH3)2 (Cys-OCH3 = the anion of the carboxylate ester of cysteine) which is known to be square pyramidal with bonding of trans sulfur atoms and trans nitrogen atoms to vanadium. The oxidation of VO(Pen-OCH3)2 in DMSO is a reversible process at 0.3 V versus SCE followed by a rapid chemical reaction of the initial product. Controlled potential coulometric oxidation did not give reproducible results until a ruthenium mediator was added. Under these conditions the coulometric data indicated a one electron oxidation, as previously reported for VO(Cys-OCH3)2. Thus, these two vanadyl compounds exhibit similar one electron oxidations giving vanadium(V) products.
Thermodynamics of vanadyl(IV)—carboxylate complex formation in aqueous solution
作者:Plinio Di Bernardo、Giuliana Tomat、Pierluigi Zanonato、Roberto Portanova、Marilena Tolazzi
DOI:10.1016/s0020-1693(00)83971-7
日期:1988.5
Abstract The stability constants and the heats of formation of vanadyl(IV)—acetate, —glycolate, and —glycine complexes have been determined in aqueoussolution by means of potentiometric and calorimetric measurements. In the pH range where the protolitic equilibria of VO 2+ is certainly negligible the acetate forms two mononuclear complexes, the glycolate three whereas the glycine reacts in its zwitterionic
Synthesis, crystal structure and molecular conformations, and magnetic properties of a copper-vanadyl (CuII-VOII) heterobinuclear complex: interaction between orthogonal magnetic orbitals