Synthesis and Structure of Group 14 Element Derivatives of Carbotelluroates

Abstract

Group 14 element derivatives of carbotelluroates, RCOTeMPh 3 (M = Ge, Sn, Pb), were synthesized as stable compounds by reacting sodium carbotelluroates with Ph 3 MCl and were characterized by IR and 13 C and 125 Te NMR spectra. Their molecular structures were revealed by X-ray molecular analysis. The C O···Sn distance in RCOTeSnPh 3 was found to be shorter than the C O···Ge distance in RCOTeGePh 3, despite the fact that the atomic radius of Sn is larger than that of Ge. A similar shortening of the nonbonding distance was observed for the corresponding selenium derivatives. Molecular orbital calculations of model compounds, i.e., CH 3 COEM(CH 3 ) 3 (E = Se, Te; M = Ge, Sn, Pb), at the B3LYP/LANL2DZ+p level also supported this shortening of the C O···Sn distance. NBO (natural bond orbital) analyses of the model compounds showed that two types of orbital interactions, n O →σ* ME and n O →σ* MC (E = S, Se, Te; M = Ge, Sn, Pb), are important in these carbochalcogenoates. Furthermore, the former interaction has a greater role in the case of carbothioates, whereas the latter is dominant in carbotelluroates.