(^tBu₂MeSi)₂SnSn(SiMe^tBu₂)₂:  A Distannene with a >SnSn< Double Bond That Is Stable Both in the Solid State and in Solution

Abstract

((t)Bu(2)MeSi)(2)Sn=Sn(SiMe(t)Bu(2))(2) 1, prepared by the reaction of (t)Bu(2)MeSiNa with SnCl(2)-diox in THF and isolated as dark-green crystals, represents the first example of acyclic distannene with a Sn=Sn double bond that is stable both in the crystalline form and in solution. This was proved by the crystal and NMR spectral data of 1. Distannene 1 has these peculiar structural features: a shortest among all acyclic distannenes Sn=Sn double bond of 2.6683(10) A, a nearly planar geometry around both Sn atoms, and a highly twisted Sn=Sn double bond. The reactions of 1 toward carbon tetrachloride and phenylacetylene also correspond to the reactivity anticipated for the Sn=Sn double bond. The one-electron reduction of 1 with potassium produced the distannene anion radical, the heavy analogue of alkene ion radicals, for which the particular crystal structure and low-temperature EPR behavior are also discussed.

Differentiation rather than aging of muscle stem cells abolishes their telomerase activity

“…B. in der quantitativen Chlorierung mit CCl4 zum 1,2‐Dichlordistannan. Durch Reduktion von (50) wird erstmalig ein Radikalanion eines Distannens erhalten, das im Festkörper sowohl ein planares als auch ein stark pyramidalisiertes Sn‐Atom aufweist und dessen Sn‐Sn‐Bindung (2,8978 Å) um 0,2295 Å länger als im neutralen Edukt ist 70). Es konnte auch das Radikalanion [Bbt‐SbSb‐Bbt]�?− eines Distibens röntgenographisch charakterisiert werden (Bbt = 2,6‐{(Me3Si)2CH}2‐ 4‐{(Me3Si)3C}C6H2), dessen Sb‐Sb‐ Abstand mit 2,7511 Å zwischen dem einer Einfach‐ und einer Doppelbindung liegt 71)…”

Dispersion Energy Enforced Dimerization of a Cyclic Disilylated Plumbylene

“…This behavior is illustrated by Sekiguchi’s distannene ( t Bu 2 MeSi) 2 Sn=Sn(SiMe t Bu 2 ) 2 that despite bearing bulky groups on the tin atoms does not dissociate into monomers in solution. 6 …”

A Cyclic Disilylated Stannylene: Synthesis, Dimerization, and Adduct Formation

“…In addition, the Sn=Sn bonds in 3 are twisted by angles ε of 27.0 and 28.6°. Comparison with the structural parameters of two closely related compounds, namely, the dimeric structure [(Me 3 Si) 3 Si] 2 Sn ( 7 )(4) and Sekiguchi’s compound 6 ,(14) reveals an amazing structural diversity of silyl-substituted stannylene dimers [for 6 , d (Sn=Sn) = 266.8 pm, β = 1.2°, ε = 44.6°; for 7 , d (Sn=Sn) = 282.5 pm, β = 28.6°, ε = 63.2°]. These pronounced differences suggest a high structural flexibility of the Si 2 Sn=SnSi 2 core in distannenes 3 , 6 , and 7 .…”