85601-08-7Relevant academic research and scientific papers
Synthesis and reactions of thermally stable platinum(II) carboxylic acids (hydroxycarbonyls) containing bis(tertiary phosphines)
Bennett, Martin A.,Rokicki, Andrzej
, p. 180 - 187 (1985)
Platinum(II) carboxylic acids (or hydroxycarbonyls) of general formula Pt(CO2H)(C6H9)(P-P) (C6H9 = 1-cyclohexenyl; P-P = Ph2PCH2CH2PPh2 (1), cis-Ph2PCH=CHPPh2 (2), Ph2PCH2CH2CH2PPh2 (3), and Ph2PCH2CH2CH2CH2PPh 2 (4)) have been prepared by the successive reaction of water and carbon monoxide with the cyclohexyne complexes Pt(C6H8)(P-P). Complex 3 readily inserts a second molecule of CO into the platinum(II)-cyclohexenyl bond to give an acylplatinum(II) carboxylic acid, Pt(CO2H)-(COC6H9)(Ph2PCH 2CH2CH2PPh2) (5). The complexes, which have been characterized by elemental analysis, IR spectroscopy and 1H, 13C, and 31P NMR spectroscopy, are monomeric in dichloromethane but appear to be associated through hydrogen bonds in the solid state. Complexes 1-5 do not decarboxylate in the solid state up to ca. 80°C and do not form carboxylate ions by loss of a proton. These properties probably arise from the presence of nondissociating, strongly electron-donating ligands in the coordination sphere. The platinum(II) carboxylic acids do readily undergo esterification with alcohols, and 3 reacts with dimethylamine or tert-butylamine to give carbamoyl complexes Pt(CONR1R2)(C6H9)(Ph 2PCH2CH2CH2PPh2) (R1 = R2 = Me, 6; R1 = t-Bu, R2 = H, 7). These reactions, and the ready exchange of 13CO with the Pt-CO2H group, indicate that the carboxylic acids behave as [Pt(C6H9)(CO)(P-P)]OH, although the carbonyl cations could not be detected in solutions of the acids. Treatment of 5 with HBF4 gives [Pt(COC6H9)(CO)-(Ph2PCH2CH 2CH2PPh2)]BF4, as expected, whereas 3 undergoes competitive cleavage of the platinum-(II)-cyclohexenyl bond and consequent β-elimination of CO2 from the Pt-CO2H group.
