Vibrational spectroscope of complexes of platinum(0)—I. Tetrakis(triphenylphosphine)platinum(0) and Dioxygenbis(triphenylphosphine)platinum(0)

Abstract Assignment of i.r. and Raman spectra for Pt(PPh 3 ) 4 and Pt(O 2 )(PPh 3 ) 2 yielded values for νPtP of 137 and 157 cm −1 (Pt(PPh 3 ) 4 ); 132 (antisymmetric) and 145 cm −1 (symmetric) (Pt(O 2 )(PPh 3 ) 2 ). For the dioxygen complex, solution phase Raman spectra gave values for both ν PtO 2 modes for the first time. Data from the 16 O 2 , 16 O 18 O and 18 O 2 isotopomers were used in a normal coordinate analysis of the PtO 2 fragment. The OO stretching force constant (3.0 mdyn A −1 ) is consistent with extensive net π-back-donation into the π* m.o.s of the O 2 ligand.