Mechanism of the Addition of Nonenolizable Aldehydes and Ketones to (Di)metallenes (R2X=YR2, X = Si, Ge Y = C, Si, Ge): A Density Functional and Multiconfigurational Perturbation

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• 作者：Nicholas J. Mosey ; Kim M. Baines ; and Tom K. Woo
• 刊名：Journal of the American Chemical Society
• 出版年：2002
• 出版时间：November 6, 2002
• 年：2002
• 卷：124
• 期：44
• 页码：13306 - 13321
• 全文大小：211K
• 年卷期：v.124,no.44(November 6, 2002)
• ISSN：1520-5126

文摘

The mechanism of the addition of nonenolizable aldehydes and ketones to group 14 (di)metalleneshas been examined through a theoretical study of the addition of formaldehyde to Si=C, Ge=C, Si=Si,Si=Ge, and Ge=Ge bonds at the B3LYP/6-311++G(d,p) and CAS-MCQDPT2/6-31++G(d,p) levels oftheory. The reaction pathways located can be grouped as either involving the formation of singlet diradicalor zwitterionic intermediates or as concerted processes. Within each group of reaction pathways, severaldifferent mechanisms have been located, with not all mechanisms being available to all of the (di)metallenes.It was found that for reactions in which a Si-O bond results (i.e., addition to Si=C, Si=Si, and Si=Ge)both diradical and zwitterionic intermediates are possible; however, the formation of diradical intermediateswas not found for reactions that result in the formation of a Ge-O bond (addition to Ge=C and Ge=Ge).The underlying cause of this pathway selectivity is examined, as well as the effect of solvent on the relativeenergies of the pathways. The results of the study shed light on the cause of experimentally obtainedresults regarding the mechanism of the reaction of (di)metallenes with nonenolizable ketones and aldehydes.