Low-coordinate compounds of heavy group 14 elements (Si, Ge, Sn and Pb) are an important novel group of main group chemistry. In recent years, many new compounds of this type with unprecedented structures were synthesized and their use for transition metal free activation of small molecules emerged as an attractive option. My Ph.D. research focused on the synthesis, characterization and reactions of novel low-coordinate Ge and Sn compounds with unusual structures and unique electronic properties. My seminar is divided into three main parts. In the first part a new method for the generation of heavy tetrylenes, R2E: (E = Ge, Sn), via reductive elimination of silane from silyl-substituted stannane and germane, will be presented. Reactions of these tetrylenes yielding synthetically challenging polycyclic products such as E-cubanes will be also presented.1 The synthesis, characterization and reactions of the first planar non-twisted distannene R2Sn=SnR2, a tin analog of an alkene, will be presented in the second part.2 In contrast to the planar structure of alkenes, all previously reported distannenes have a distorted structure, with either a trans-bent and/or twisted geometry around the Sn=Sn double bond. We synthesized the first distannene featuring a planar geometry around both Sn atoms, a non-twisted Sn=Sn bond, and the shortest known Sn=Sn bond (2.599 Å) among all known acyclic distannenes. This unique combination of structural properties closely resembles the structure of classic alkenes. In the final part I will discuss the chemistry of the first stable lithium stannenolate (a tin analog of an enolate).3 The interesting question, “what is the dominant structure of stannenolate? keto or enol?”, was studied both experimentally and computationally. Spectroscopic and structural features and reactions, in combination with DFT quantum-mechanical calculations, indicate that the stannenolate is best described as an acyl-substituted stannyl anion, adopting the keto tautomeric structure. Overall, my research contributes to the fundamental knowledge and understanding of the structural, spectroscopic, and bonding differences within low-coordinate compounds of group 14 elements.
References:
1. R. Bashkurov, A. Kaushansky, B. Tumanskii, N. Fridman, D. Bravo-Zhivotovskii, Y. Apeloig, Angew. Chem. Int. Ed. 2023, 62, e202300847.
2. R. Bashkurov, N. Fridman, D. Bravo-Zhivotovskii, Y. Apeloig, Chem. Eur. J. 2023, 29, e202302678.
3. R. Bashkurov, N. Fridman, D. Bravo-Zhivotovskii, Y. Apeloig, Dalton Trans. 2021, 50, 13651-13655.