Platinum(II) O,O′-diisobutyl dithiophosphate: Synthesis, structure, thermal properties, and solid-state 13C, 31P, and 195Pt CP/MAS NMR spectra. Model of the structural state of platinum in cooperite

Abstract

The complex bis(O,O′-diisobutyl dithiophosphato)platinum(II) (I) was obtained and characterized by solid-state 13C, 31P, and 195Pt CP/MAS NMR spectroscopy. In complex I, the dithiophosphate fragments are structurally equivalent with a predominantly orthorhombic tensor of the 31P chemical shift (η = 0.73). The tensor of the 195Pt chemical shift approximates to an axially symmetric one (for δzz> δxx and δyy), which suggests the existence of square chromophores [PtS4], as in cooperite (natural PtS). The crystal and molecular structures of complex I were determined from X-ray diffraction data. The Pt atom coordinates two Dtph ligands in a S,S′-anisobidentate fashion (the Pt-S bonds are nonequivalent: 2.315 and 2.329 A) to form two four-membered chelate rings [PtS2P] with platinum as a spiro atom. The P-S bond length (1.997 and 1.986 A), which is intermediate between the idealized lengths of the single and double phosphorus-sulfur bonds, suggests the delocalization of the π-electron density in the structural fragments PS2. In complex I, the electron shielding of the platinum nucleus in the direction perpendicular to the plane of the chromophore [PtS4] was found to be noticeably higher than that in cooperite. The thermal properties of complex I were examined by combined DSC-TG thermal analysis. The intermediate product of the thermolysis of complex I was platinum(II) dithiometaphosphate [Pt(S2PO)2] and the final thermolysis product was PtS.