71080-85-8Relevant articles and documents
Reactivity and ligand exchange in triplatinum clusters
Browning, Clive S.,Farrar, David H.,Gukathasan, Ravi R.,Morris, Stephen A.
, p. 1750 - 1754 (2008/10/08)
The phosphine ligands, L, in the triplatinum clusters Pt3(CO)3L3 have been found to undergo a facile ligand substitution reaction with 3 equiv of L′ to give Pt3(CO)3L′3 where L = P-t-Bu3 and L′ = P-t-Bu2Ph, L = P-t-Bu2Ph and L′ = P-t-BuPh2, PCy3, and P-i-Pr3, and L = PCy3 and L′ = P-i-Pr3. The substitution occurs by an associative mechanism with the Pt3 triangle remaining intact during the process. Mixtures of Pt3(CO)3(P-t-Bu2Ph)3, 1, and either Pt3(13CO)3(P-t-Bu2Ph)3 or Pt3(CO)3(PCy3)3, 2, scramble both phosphine and carbonyl ligands in a much slower reaction (approximately 1 h at 25 °C whereas L′ substitution occurs in about 25 s). Reactions of the cluster 1 with CS2, OCS, and SO2 also have been examined. In all cases, fragmentation of the trimer occurs to give dimeric products. The reaction of 1 and CS2 results in formation of either Pt2(μ-CS2)2(P-t-Bu2Ph) 2, or Pt2(μ-S)(CO)2(P-t-Bu2Ph)2, 4, depending on reaction conditions, whereas 4 is obtained from the reaction of 1 with OCS. Treatment of 1 with SO2 at 25 °C gives Pt2(μ-SO2)-(CO)2(P-t-Bu2Ph) 2, 5, which on prolonged standing in solution at 25 °C converts to the triplatinum cluster Pt3(CO)2(SO2) (P-t-Bu2>Ph)3, 6. 31P NMR spectroscopy reveals that the initial reaction gives mixtures of 5, 6, and Pt3(SO2)2(CO)(P-t-Bu2Ph) 3.