With silthians

The names of compounds containing silicon atoms as heteromembers (with or without other heteromembers) but not classifiable as (linear or cyclic) silanes, silazanes, silthianes or siloxanes are derived with the aid of the oxa-aza convention. Examples ... 

The Si—S bond has some similarities with the Si—O bond. However, its resistance to cleavage by nucleophilic reagents is considerably smaller. In contrast to the C—S bond the Si-S linkage very readily undergoes solvolytic cleavage in water and alcohols. Silthianes are hydrolyzed even by atmospheric moisture, leading to the corresponding silanols. 

Aryl nitriles with (Me3Si)2S in the presence of MeONa/l,3-dimethyl-2-imidazolidinone results in the conversion to primary thioamides, while amides and lactams yields the thio derivative using (Me3Si)2S and an oxophilic promoter such as POCI3, triphosgene or oxalyl chloride. Thus the intermediate [CIRC=NR R"]+C1 reacts with the silthiane to give the thioamide (equation 24)44. 

Di(silyl)benzene gives the di(chlorosilyl)benzene reagent upon treatment with boron trichloride (Scheme 3). Contrary to the parent compound, this derivative is readily solvolyzed and gives cyclic siloxanes, silthianes, silazanes and silylphosphines on contact with water, hydrogensulfide, ammonia, amines, or phosphines, respectively. 

H Caution. Hexamethyldisilthiane appears to have an effect on the nervous system. Skin contact with the liquid or breathing of the vapor should be avoided. This compound should be handled only in a good hood. It has a very strong odor reminiscent of mercaptans. If silthiane vapors are allowed to escape into the air, a flood of gas-leak reports will be made and personnel will evacuate the building because they think that there is a gas leak. As a result, no article which has contacted the sulfide should be allowed out in the open room. 

Diphenyl ketene behaves similarly30. With phenyl isothiocyanate, however, no silthiane is eliminated and the adduct equilibrium is dominated by the phosphathiourea isomer (equation 24)31. With carbon disulphide, a red zwitterion intermediate forms at first, then decomposes to the dithiomethylene derivative rather than, as with carbon dioxide, the phosphacarbamic ester (equation 25)32. A similar reaction occurs with (Me3Si)2PMe, but... 

Organosilicon-sulphur compounds will be considered under six headings defined by structure type. Organothiosilanes RnSi(SR )4 , linear and cyclic silthianes with the SiSSi... 

Hexamethyldisilthiane can be conveniently prepared from Na2S, freshly synthesized from the elements in THE with naphthalene, silylation with MesSiCl giving the silthiane in 90-95% yield. 1,3-Diphenyldisilthiane results from H2S, PhH2SiCl and EtsN in 83% yield, in contrast to the time-consuming frawi-silylation of (Me3Si)2S with PhSiH2Cl when only 40% yield could be obtained . ... 

The structures and conformations of cyclic and polycyclic silthianes containing Si-Si bonds have been studied at the B3LYP/6-31G level. The most stable structures contain SisS2 rings with Si-S-Si-S-Si- connectivity. 

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