Disilanes reactions with sulfur

The reaction of the acetylene silanes and disilanes 197a and 197b with sulfur in the presence of butyllithium afforded bis-(silanylmethylene)-l,3-dithietanes 198a and 198b (yields not reported) (Equation 36) <2001JA6209>. 

DOT CLASSIFICATION 2.2 Label Nonflammable Gas SAFETY PROFILE This material is chemically inert in the pure state and is considered to be physiologically inert as well. However, as it is ordinarily obtainable, it can contain variable quantities of the low-sulfur fluorides. Some of these are toxic, very reacdve chemically, and corrosive in nature. These materials can hydrolyze on contact with water to yield hydrogen fluoride, which is highly toxic and very corrosive. In high concentrations and when pure it may act as a simple asphjudant. Incompatible with disilane. Vigorous reaction with disilane. May explode. When heated to decomposition emits highly toxic fumes of F" and SOx. 

A silacyclopropene intermediate 56 was trapped by a reaction with 2-propanol during the thermal degradation of pentacoordinate disilanes 55 bearing an 8-thiona- or 8-seleno-l-naphthyl group and a methoxy group on the same silicon center. This reaction generates intramolecular sulfur- or selenium-coordinated silylenes 57 (Scheme 10) <2003OM3299>. 

SULFUR FLUORIDE (2551-62-4) Hydrolyzes in hot water, forming hydrofluoric acid. Violent reaction with chromyl chloride, diethylzinc, dimethyl sulfoxide, disilane, lead dioxide, nitric acid, red phosphorus, potassium, sodium peroxide. Incompatible with hexafluoroisopropylideneaminolithium. 

The cleavage of Si—CH3 bonds in hexaalkyldisilanes with concentrated sulfuric acid, followed by treatment with an ammonium halide has provided access to a variety of 1- and 1,2-halogenated disilanes 2). The course of the reaction can be followed by observation of the amount of methane evolved. 

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