Related Experiment Video
Updated: Jul 19, 2026

Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites
Published on: February 6, 2016
Tetrakis(di-tert-butylmethylsilyl)distannene and its anion radical
Tomohide Fukawa1, Vladimir Ya Lee, Masaaki Nakamoto
1Department of Chemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
Abstract:
Tetrakis(di-tert-butylmethylsilyl)distannene 1 was synthesized by the coupling reaction of tBu2MeSiNa with SnCl2-diox in THF and isolated as dark-green crystals. X-ray analysis of 1 showed the shortest Sn=Sn double bond (2.6683(10) A) among all acyclic distannenes, an almost planar geometry around the Sn atoms, and a highly twisted Sn=Sn double bond. The reaction of distannene 1 with CCl4 produced 1,2-dichlorodistannane 2, implying that 1 does not dissociate into stannylenes, both in the solid state and in solution. The one-electron reduction of 1 with potassium furnished the corresponding distannene anion radical 3, the stable ion radical of the heavy alkene analogues, which has been fully characterized by X-ray crystallography and ESR spectroscopy.
Related Concept Videos
Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Diels–Alder Reaction: Characteristics of Dienes
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable, the...
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry

