Reaction of organoboron compounds with platinum(II) disolvento complexes

Article abstract of DOI:10.1021/om00113a023

Cationic complexes cis-[Pt(S)₂L₂]²⁺ (L = PMe₃, PEt₃, or PPh₃; S = H₂O or MeOH) react with arylboron derivatives ([BPh₄]^-, [B(p-Tol)₄]^-, [B(m-Tol)₄]^-, BPh₃, B(OMe)Ph₂, B(OMe)₂Ph, and B(OH)₂Ph) to give trans-[Pt(Ar)(S)L₂]⁺ which are isolated and characterized as their halo derivatives trans-[PtX(Ar)L₂]. When L = PMe₃, the transient formation of cis-[Pt(Ar)(S)L₂]⁺ is also observed. The cation cis-[Pt(CH₃CN)₂-(PEt₃)₂] ²⁺, however, reacts with [BPh₄]^- only when at least some of the solvent is hydroxylic. However the phenylation and cis-trans isomerization reactions are slowed down so that the intermediate formation of cis-[Pt(Ph)(CH₃CN)(PEt₃)₂]⁺ cation can be observed. It is shown that [BPh₄]^- is not the phenylating agent as it decomposes to BPh₃ and C₆H₆ prior to the phenylation reaction. Other phenylboron derivatives such as BPh₃, B(OMe)Ph₂, B(OMe)₂Ph, and B(OH)₂Ph can transfer all of their phenyl groups to platinum. It is found that the phenyl transfer is strictly regioselective; i.e., only the C atom bonded to boron is found coordinated to platinum. When [B(Me)(Ph)₃]^- is used, either a methyl or a phenyl group can be transferred to platinum.