Synthesis and characterization of new platinum(II) phosphinate complexes

The syntheses of platinum(II) complexes of bis(dimethylphosphinylmethylene)amine and bis(aminomethyl) phosphinic acid were investigated. In the case of bis(dimethyl-phosphinyl-methylene) amine the reaction with K-2[PtCl4] yields the potassium amino-trichloroplatinate K[PtCl3L] (L = bis(dimethylphosphinylmethylene) amine), which was characterized by multinuclear (H-1, C-13, P-31, and Pt-195) NMR spectroscopy in solution. Bis(aminomethyl) phosphinic acid reacts with K-2[PtCl4] under strictly controlled pH conditions to give colorless crystals of the cisplatin analog K[PtCl2L'] (L' = bis(aminomethyl)phosphinate). This complex was characterized by multinuclear NMR spectroscopy in solution as well as by single-crystal X-ray diffraction in the solid state. The bis(aminomethyl) phosphinate coordinates to platinum via both amino functions, thus acting as a chelating ligand.