PENTACOORDINATE DIORGANOTIN HALIDES CONTAINING A RIGID, FLAT CHELATE RING. AN UNEXPECTED REDISTRIBUTION REACTION BETWEEN TRIMETHYLTIN AND TRIMETHYLTIN HALIDE

Article abstract of DOI:10.1016/S0022-328X(00)99320-3

The tetraorgano- and triorgano-halotin compounds Me3(8-Me2NC10H6)Sn and RR'(8-Me2NC10H6)SnX (R=R'=Me or Ph, X=Cl or Br and R=Me, R'=Ph, X=Br) have been obtained from the 1/1 reaction of 8-dimethylamino-1-naphthyllithium (8-Me2NC10H6Li) with the relevant organotin halide (Me3SnCl or RR'SnX2).On the basis of the 1H NMR data a trigonal bipyramidal structure with intramolecular Sn-N coordination is proposed for the RR'(8-Me2NC10H6)SnX compounds, in which the organo ligands occupy the equatorial and the N and X atoms the axial positions.The Sn center in chiral MePh(8-Me2NC10H6)SnBr has considerable configurational stability (at least on the NMR timescale, 60 MHz): the Me groups of the coordinated NMe2 group remain diastereotopic up to at least 120 deg C.This relatively high stability is ascribed to the fixed position of the Sn and N atoms respectively connected to the 1- and 8-positions of the flat naphthyl ring.Reaction of Me3SnX with Me3(8-Me2NC10H6)Sn results in quantitative formation of Me4Sn and Me2(8-Me2NC10H6)SnX (X=Cl, Br).Overcrowding in the 8-Me2N-1-Me3SnC10H6 compound as well as the formation of the Sn-N bond are suggested as driving forces for this Me/Cl exchange reaction.This methylating property of 8-Me2N-1-Me3SnC10H6 also leads to quantitative formation of MePtCl(COD) from PtCl2(COD) at room temperature.