Synthesis and Structure of Group 14 Element Derivatives of Carbotelluroates
journal contributionposted on 2002-02-26, 00:00 authored by Kazuyasu Tani, Ryo Yamada, Takahiro Kanda, Masahiro Suzuki, Shinzi Kato, Toshiaki Murai
Group 14 element derivatives of carbotelluroates, RCOTeMPh3 (M = Ge, Sn, Pb), were synthesized as stable compounds by reacting sodium carbotelluroates with Ph3MCl and were characterized by IR and 13C and 125Te NMR spectra. Their molecular structures were revealed by X-ray molecular analysis. The CO···Sn distance in RCOTeSnPh3 was found to be shorter than the CO···Ge distance in RCOTeGePh3, 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., CH3COEM(CH3)3 (E = Se, Te; M = Ge, Sn, Pb), at the B3LYP/LANL2DZ+p level also supported this shortening of the CO···Sn distance. NBO (natural bond orbital) analyses of the model compounds showed that two types of orbital interactions, nO→σ*ME and nO→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.