Preparation and characterization of triorganotin(IV) derivatives of mercaptocarboxylic acids. Crystal structure of [ O, S-bis(triphenyltin(IV))-2-mercaptobenzoate

Abstract

The syntheses and tin-119m Mössbauer spectroscopic data are reported for the tri-n-butyl-, tricyclohexyl- and triphenyltin(IV) derivatives of mercaptoacetic and 2-mercaptobenzoic acids. A four-coordinate tetrahedral geometry at tin is assigned for (cyclo-C 6H 11) 3SnSCH 2C(O)OH and for the (C 6H 5) 3SnSCH 2C(O)O − and (C 6H 5) 3SnSC 6H 4C(O)O − anions, isolated as the dicyclohexylammonium and iso- S-benzylthiuronium salts, respectively. The sulfidotin in R 3SnSCH 2C(O)OSnR 3 and R 3SnSC 6H 4C(O)OSnR 3 is also four-coordinate, but the carboxylatotin is four-coordinate for R = C 6H 5 and five-coordinate for R = n-C 4H 9. The Mössbauer quadrupole splitting in the butyltin case indicates a trans-C 3SnO 2 trigonal bipyramidal configuration. The coordination assignment for the two tin atoms in bis(triphenyltin)-2-mercaptobenzoate is confirmed by X-ray crystallography. The compound crystallizes in space group P2 1/ c with a 14.293(4), b 17.456(2), c 15.624(1) Å, β 107.40(1)°; Z = 4. The structure was refined to an R factor of 0.035 for 5837 observed reflections. The carbonyl oxygen of the molecule is positioned roughly halfway between the carboxylatotin (Sn ⋯ O 2.765(3) Å and sulfidotin (Sn ⋯ S 3.016(1) Å, disorting somewhat the tetrahedral geometries at both tin sites.