~(31)P NMR STUDIES OF REDOX REACTIONS OF BIS (TRIALKYLPHOSPHINE) GOLD(I) BROMIDE (ALKYL = METHYL, ETHYL) WITH DISULPHIDE AND DISELENIDE LIGANDS

摘要

Redox reactions of bis (trialkylphosphine) gold(I) bromide (alkyl = methyl, ethyl) with two diselenides (R'Se-SeR'), selenocystine and selenocystamine and their corresponding disulfides were studied in D_2O by ~(31)P NMR spectroscopy. Upon interaction of diselenides with (Me_3P)_2AuBr or with (Et_3P)_2AuBr, the Se-Se bond is broken, resulting in the formation of R_3PAu~+, R'SeH, R'Se-Au-PR_3, R_3PO and (AuSeR')_n. Second-order rate constants were determined for the decomposition of (R_3P)_2AuBr. Selenocystamine reacts with (Et_3P)_2AuBr about 100 times faster than its corresponding disulfide. However, cystamine reacts twice as fast with (Me_3P)_2AuBr compared to its corresponding diselenide.