Additive model for 119Sn Mössbauer quadrupole splitting in five-co-ordinate organotin(IV) compounds

Abstract

Mössbauer parameters are reported for ten cationic organotin(IV) complexes of type [R₃SnL₂][BPh₄](R = alkyl or phenyl, L = electrongegative ligand). Details are given of a regression method which is used to distinguish structural isomers of trigonal-bipyramidal [R₃SnL₂] species by their ¹¹⁹Sn quadrupole splittings. By use of new and literature data, partial quadrupole splitting (p.q.s.) parameters are calculated for a variety of ligands in trigonal-bipyramidal structures. Comparison of theory with experiment indicates that the additive model gives a consistent account of the relationship between quadrupole splitting and stereochemistry in trigonal-bipyramidal organotin(IV) compounds. The ¹¹⁹Sn parameters are used to calculate p.q.s. parameters for ¹²¹Sb^V, thus extending recent work on application of the additive model to five-co-ordinate organoantimony(V) compounds.