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Synthesis and Structure of Group 14 Element Derivatives of Carbotelluroates

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journal contribution
posted 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 CO···Sn distance in RCOTeSnPh3 was found to be shorter than the CO···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 CO···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.