Reactions of organotin(IV) compounds with platinum complexes. Part(III). Reactions of (R2Sn)n, (R=Me or Ph, n=6; R=Et, n=9) with platinum complexes

The R2Sn moieties formed when the cyclic compounds (R2Sn)n, R=Me or Ph, n=6; R=Et, n=9, are exposed to light, react with the platinum(II) complexes [PtCl2L2], L=PEt3, PPr3, PBu3, PEtPh2, PPh3 to give new complexes of the general formula [PtCl(SnR2Cl)L2]. Similarly, Et2Sn from (Et2Sn)9 reacts with [PtMe(Cl)L2] to give [PtMe(SnEt2Cl)L2] and Ph2Sn from (Ph2Sn)6 reacts with [PtPh(Cl)L2] or [PtPh2L2] to give [PtPh(SnPh2Cl)L2] or [PtPh(SnPh3)L2] (L=PEt3), respectively. Reactions involving (R2Sn)n and the bridged complex [{Pt(μ-Cl)ClL}2] give a mixture of [PtCl(SnR2Cl)L2] and [PtCl(SnRCl2)L2], R=Me or Et, L=PBu3. It is suggested that these reactions initially involve insertion of R2Sn moieties into PtCl bonds of the complexes [PtX(Cl) L2] or [{Pt(μ-Cl)ClL}2] then generate R2SnXCl (X=Cl, Me, Ph) and the Pt(0)complex [PtL2], which undergoes oxidative-addition of the formed tin(IV) species to give complexes containing PtSn bonds. With (Ph2Sn)6 and [PtPh2L2], the mechanism takes a different course. Reactions under similar conditions involving the Pt(0) complexes [Pt(C2H4)(PPh3)2] or [Pt(COD)2], (COD=1,5-cyclooctadiene) and (R2Sn)6, R=Me or Ph, gave no detectable complexes containing PtSn bonds. The complex [Pt(PEt3)4] and (MeSn)6 likewise gives no species containing PtSn bonds but with (Ph2Sn)6, two complexes, tentatively identified as trans-[PtPh(Sn2Ph5)(PEt3)2] and trans-[PtPh(Sn6Ph11)(PEt3)2], were detected in the solution. In all cases, the products were identified by 31P-NMR spectroscopy.