Silicon dithiocarbamate complexes

Although silicon dithiocarbamate complexes remain rare, complexes of the type [SiR2(S2CNR2)2] (R = Me or Ph) have been reported recently (82). Spectroscopic data for the complexes (IR and NMR) have been interpreted in terms of a tetracoordinate silicon atom, with the two dithiocarbamate ligands monodentate. 

Early examples were restricted to the insertion into sulfur-hydrogen bonds (214-216). For example, addition of phenylisothiocyanate to [Au(SH)2] affords the bis(dithiocarbamate) complex [Au(S2CNHPh)2] (216). More recently, Shaver and co-workers (217) demonstrated a similar insertion into the sulfur-silicon bond of [CpRu(PPh3)2(SSi-i-Pr3)], yielding unusual silicon-substituted dithiocarbamate ligands (Eq. 35). 

Four main types of antioxidants are commonly used in polypropylene stabilizer systems although many other types of chemical compounds have been suggested. These types include hindered phenolics, thiodi-propionate esters, aryl phosphites, and ultraviolet absorbers such as the hydroxybenzophenones and benzotriazoles. Other chemicals which have been reported include aromatic amines such as p-phenylenediamine, hydrocarbon borates, aminophenols, Zn and other metal dithiocarbamates, thiophosphates, and thiophosphites, mercaptals, chromium salt complexes, tin-sulfur compounds, triazoles, silicone polymers, carbon black, nickel phenolates, thiurams, oxamides, metal stearates, Cu, Zn, Cd, and Pb salts of benzimidazoles, succinic acid anhydride, and others. The polymeric phenolic phosphites described here are another type. 

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