The Mössbauer recoil-free fraction and structure: IV. Triphenyltin derivatives of methionine, penicillamine and cysteine and l-histidinatotin(II)

Abstract

Tin-199 Mössbauer isomer shift, quadrupole splitting and resonance area data have been recorded in the temperature range 77–150 K for the four triphenyltin complexes, O-triphenylstannylmethionine (Ph 3Snmet), its methionine solvate, Ph 3Snmet·metH, O,S-bis(triphenylstannyl)penicillamine ((Ph 3Sn) 2pen) and O,S-bis(triphenylstannyl)cysteine ((Ph 3Sn) 2cys) as well as l-histidinatotin(II) (HisSn). In the solid state, the structure of I comprises mainly discrete monomeric molecules with four-coordinated tin together with a small amount of a one-dimensional polymeric modification containing five-coordinated tin. The methionine solvate, Ph 3Snmet·metH, also contains discrete monomeric molecules, which are involved in hydrogen-bonding with the methionine solvate molecules. Both (Ph 3Sn) 2 pen and (Ph 3Sn) 2)cys contain two chemically-distinct tin environments, one four-coordinate where the triphenyltin residue is bound to the thiol sulphur, and a five-coordinated site where bonding is to the carboxyl group. However, (Ph 3Sn) 2 pen appears to be monomeric in the solid, whereas (Ph 3Sn) 2cys comprises a one-dimensional polymer. An essentially monomeric structure is proposed for HisSn, but with some moderately weak intermolecular association.