Reactions of a trans-diamminediaquaplatinum(II) complex with L-cysteine

Abstract

The reaction of a trans-diamminediaquaplatinum(II) complex, trans-[Pt(NH3)2(H2O)2] (1), and L-cysteine (R–SH) has been performed to confirm the formation of the products in the solution. The reaction was monitored by 1-D N and 2-D [H, N] heteronuclear single-quantum coherence (HSQC) Nuclear Magnetic Resonance (NMR) and electrospray ionization (ESI) mass spectrometry. The reaction was initially performed in an alkaline solution; the platinum mononuclear species products were observed. The pH of the solution was then decreased to an acidic solution; the products obtained were oligomeric platinum products. Based on the spectrum from mass spectrometry, which was obtained in a basic solution, the most dominant complex in the solution is a dinuclear platinum(II) species with a sulfur-bridging, trans-[{Pt(S-cys)2(NH3)2}2(S-cys)] having m/z of 822. The loss of two successive ammines was observed.