Sterically-induced low temperatur polyhedral rearrangements of carbaplatinaboranes: Synthesis and crystal structures of 1-Ph-3,3-(PMe 2Ph) 2-3,1,2-PtC 2B 9H 10, 1-Ph-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 10, 11-Ph-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 10 and 1,11-Ph 2-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 9

Abstract

Reaction of cis-Pt(PMe 2Ph) 2Cl 2 with Tl 2[7-Ph-7,8- nido-C 2B 9H 10] affords 1-Ph-3,3-(PMe 2Ph) 2-3,1,2-PtC 2B 9H 10, mild thermolysis (55°C) of which yields 1-Ph-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 10 and 11-Ph-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 10. Both of the latter compounds are produced by the microwave irradiation of a mixture of cis-Pt(PMe 2Ph) 2Cl 2 and [HNMe 3][7-Ph-7,8- nido-C 2B 9H 11]. When cis-Pt(PMe 2Ph) 2Cl 2 is allowed to react with Tl 2[7,8-Ph 2-7,8- nido-C 2B 9H 9] at room temperature the only isolable species is 1,11-Ph 2-3,3-(PMe 2Ph) 2-3,1,11-PtC 2B 9H 9. The generation of rearranged products with 3,1,11-PtC 2B 9 architectures is inconsistent with a diamond-square-diamond mechanism for the isomerisation of icosahedral heteroboranes.