690269-00-2Relevant academic research and scientific papers
Unexpected differences in reactivity between tin and lead organyl chlorides - Crystal structures of their organylphosphonium salts
Weber, Dirk,Hausner, Sven H.,Eisengr?ber-Pabst, Axel,Yun, Sanghee,Krause-Bauer, Jeanette A.,Zimmer, Hans
, p. 125 - 134 (2004)
Pentacoordinated tin is known since the late 1950s but little is known about the ability of lead to form similar structures. Originally we investigated the reaction between a number of tetraorganylphosphonium chlorides [PR4]+Cl- (R=Me, Bun, and Ph) and several diorganyltin dichlorides SnR′2Cl2 (R′=Me, Et, Prn, Bun, Ph, o-, m-, p-Tol) between 100 and 240°C. Novel pentacoordinated tin complexes, tetraorganylphosphonium diorganyltrichlorostannates [PR4] [SnR′2Cl3] (1-19), were formed in good to excellent yields. In a second step, this synthetic approach was extended to include the reaction of diphenyllead dichloride Ph2PbCl2 with [PR 4]+Cl- (R=Bun, Ph). Surprisingly, a two chloride transfer was observed to form the hexacoordinated lead species [PBu4n]2[PbPh2Cl4] (20). Under similar conditions, the pentacoordinated [PPh4][PbPh 3Cl2] (21) was obtained by a phenyl transfer. Complexes 20 and 21 were characterised by NMR (1H, 13C, 31P, and 207Pb), IR, MS, and X-ray crystallography. The anion of 20 assumes a lightly distorted octahedral geometry with the phenyl substituents in trans-positions. In the anion of 21 the phenyl substituents occupy the equatorial positions of a lightly distorted trigonal bipyramid. A thorough spectroscopical investigation of the tin complexes 1-19, including X-ray structural studies, which were possible for complexes with R′=aryl, revealed that these complexes are monomeric with a distorted trigonal bipyramidal [SnR′2Cl3]- anion. Both aryl groups occupy equatorial positions.
