Synthesis and characterization of platinum(II) complexes of L-ascorbic acid.: Crystal structure of ascorbato-C2,O5-ethylenediamineplatinum(II) dihydrate

Reactions between diaminediaquaplatihum complexes [Pt((NN)-N-boolean AND)(H2O)(2)](2+) and sodium ascorbate (NaHAsc) have been studied using H-1 and Pt-195 NMR spectroscopy. Mixtures of platinum ascorbate species were formed involving different binding modes of the ascorbate ligand, namely, [Pt(HAsc-O-3)(H2O)((NN)-N-boolean AND)](+), in which a single ascorbate acts as a monodentate ligand, the bis(ascorbate)platinum complexes [Pt(HAsc-0(3))(2)((NN)-N-boolean AND)] and [Pt(HAsc-0(3))-(HAsc-C-2)((NN)-N-boolean AND)], and [Pt(Asc-0(2),0(3))((NN)-N-boolean AND)] and [Pt(Asc-C-2,0(5))((NN)-N-boolean AND)], in which the ascorbate acts as a chelating ligand ((NN)-N-boolean AND = en, N,N-dmen, N,N'-dmen, N,N,N',N'-tmen; HAsc(-) = C6H7O6-, Asc(2-) = C6H6O62-). The crystal structure of ascorbato-C-2,O-5-ethylenediamineplarinum(II) dihydrate, [Pt(Asc-C-2,0(5))(en)]. 2H(2)O, was established by X-ray crystallography. A series of diphosphineplatinum complexes of the type [Pt(Asc-0(2),0(3))((PP)-P-boolean AND)] ((PP)-P-boolean AND = dppm, dppe, dppp) was prepared from. the corresponding [Pt(NO3)(2)((PP)-P-boolean AND)] species. These have been characterized by elemental analysis and infrared and H-1 and P-31{H-1} NMR spectroscopies.