NMR investigation of platinum–diphosphine complexes in [BMIM][PF6] ionic liquid

The formation of platinum–diphosphine complexes of catalytic importance was investigated in [BMIM][PF6] (BMIM=butyl-methyl-imidazolium cation) ionic liquid by NMR for the first time. Both the PtCl(SnCl3)(bdpp) and Pt(SnCl3)2(bdpp) complexes (where bdpp=2,4-bis(diphenylphosphino)pentane) were identified in the insertion reaction of tin(II)chloride into the PtCl bond of PtCl2(bdpp) complex. The addition of PPh3 to PtCl2(bdpp) resulted in the formation of [Pt(bdpp)(PPh3)Cl]+ complex cation as a minor component, which turned to be a major component in the presence of tin(II)chloride while it forms trichlorostannate counterion. Both types of reactions show high similarity with those obtained in conventional organic solvents. As a serious disadvantage of the use of [BMIM][PF6] as ionic liquid, the partial decomposition of the hexafluorophosphate counterion in the presence of the smallest amount of water (and tin(II)chloride) is also discussed.