Cyclodisilthianes

The 2-silathietane is thought to be formed as an intermediate in the reaction of 1,1-dimethylsilacyclobutane with thiobenzophenone, since the cyclodisilthiane and 1,1-di-phenylethene are the products (Scheme 99) (75JOM(101)17l). These products support the... 

With COS, CO loss on addition gives the silathione which dimerizes to the disiladithi-etane (cyclodisilthiane). With CS2 however, the cyclodisilthiane 17 also results through carbocation rearrangement of the adduct without CS loss (Scheme 3). 

The stable silathiirane 21 results from the silene and elemental sulphur on photolysis. It has an Si—S bond of 212.9 pm, slightly longer than that found in the silathiirane formed from Mes2Sil addition to tetramethyl-2-indanethione62. In addition, the cyclodisilthiane results and can also be made from the disilabicyclo[l.l.l] pentane (20) on hydrolysis. It possesses Si-S bonds of length 217-219 pm (Scheme 4)59. 

Chemistry of compounds with Si-S, Si-Se and Si-Te bonds 1883 1,2-silathietane gives the cyclodisilthiane and the 2,4-dithia-l,3-disilacyclohexane66. 

Electron diffraction studies have been made of tetramethyl cyclodisilthiane (a) and hexamethylcyclotrisilthiane (b) ... 

The cyclodisilthianes 202 and 203 exhibit crystallographic C, symmetry so that the (SiS)2 rings are strictly planar. The Si-S-Si angles [82.5(1) and 82.2(1)°] are much narrower than the S-Si-S angles. A remarkable distortion of the silicon coordination... 

The first conclusive evidence for the intermediacy of silathiones came in 1975 from the pyrolysis of 1,1-dimethyl-1-silacyclobutane 15 with thiobenzophenone, giving a Wittig-type reaction, and forming olefin and cyclodisilthiane (equation 57)51. 2,2-dimethyl-2-... 

The cyclotrisilthiane is more stable however, when the six-membered ring is heated, cyclodisilthianes form. ... 

The equilibria in solution between the tetraatomic ring of (Me2SiS)2 and the hexaatomic ring of (Me2SiS)3 can be followed by H NMR spectroscopy . With unlike groups on the Si, cis and trans isomers are possible for the four-membered ring . When trans-1,3,5-trimethyl-l,3,5-triphenylcyclotrisilthiane is maintained at 200°C for several weeks, only one cyclodisilthiane isomer is observed ... 

Continued refluxing of l,3,5-trimethyl-l,3,5-triethyl- or 1,3,5-trivinylcyclotrisilthiane results in a 50 50 mixture of cis- and trans-cyclodisilthianes . 

Si2S2Cl4 Cyclodisilthiane, tetra-chloro-, 7 29n., 30 SiaCls Trisilicon octachloride, 1 44 SmCNOsla Samarium (III) nitrate, 6 41... 

Herzog U, Borrmann H (2003) Tetrakis(trimethylsilyl)cyclodisilthiane and -selenane. Inorg Chem Commun 6 718... 

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