Silthiane

The interest for these ligands will be probably negatively affected by the hydrolytic sensitivity of silthianes, but the cited complexes promise to be useful precursors for metal sulfur clusters. 

For designating the positions of substituents on compounds named as silanes, silazanes, silthianes, and siloxaues, each member of the fundamental chain is numbered from one terminal silicon atom to die other. When two or more possibilities for numbering occur, the same principles are followed as for carbon compounds. Examples ... 

Open-chain compounds which have the requirements for more than one of the structures already defined are named, if possible, in terms of silane, silazane, silthiane, 01 siloxane containing the hugest number of silicon atoms. Examples ... 

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. 

Sulfur lone pair ionization energies of silthianes. 210... 

HFA causes fission of Si—S bonds in acyclic 109) and cyclic 6) silthians. 

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... 

---