C-S bond energies

Several studies suggest that PFOS would have relatively low thermal stability. This conclusion is based on the fact that carbon-sulfur (C - S) bond energy is much weaker than carbon-carbon (C - C) or carbon-fluorine (C - F) bonds... 

Owing to the fact that a C—S bond energy is greater than that of a C—Te bond, the tellurium atoms in phenoxatellurines and phenotellurazines are readily replaced by sulfur under heating with elemental sulfur [93AHC(58)47]. In a similar way, 2-phenylbenzotellurazole converts to 2-phenylbenzothiazole with 42% yield... 

The C,s bond energies show that the carbene carbon atoms are less positive than those of the isocyanide group. Additions of amines, alcohols, and thiols afford many carbene complexes, particularly those of metals of groups 6-10. 

The standard enthalpy of formation of C02(g) is—394 kJ mole" , and that of CS2(g) is +115 kJ mole Calculate the enthalpies of formation of the molecules from the monatomic elements (Table V-3). By comparison with the C=0 and C=S bond-energy values (Table V-2), calculate the resonance energy for each of these molecules. (Answer 157, 204 kJ mole". )... 

A series of related alkyl and perfluoroalkyl sulphides and disulphides has been studied by photoionization and mass spectrometric techniques. Bond energies calculated from the data obtained ate listed in Table 2 bistrifluoromethyl disulphide has a particularly low C—S bond energy, and preliminary results have indicated that this compound may be a useful source of trifluoromethyl radicals. ... 

Bordwell et al., 1988, 1989) and Amett (Amett et al., 1990a,b, 1992 Venimadhavan et al., 1992) have employed thermodynamic cycles consisting of heterolysis of a molecule and redox processes of the resulting ions to evaluate homolytic dissociation energies of C—H, C—C, C—N, C—O and C—S bonds in solution. In a similar way, knowledge of the A//het(R-R ) values allows determination of the heat of homolysis of carbon-carbon bonds [A/fhomo(R"R )] using (27). The results are summarized in Table 4. 

The above relationships between the thiiranes (20) and their dioxides (17) are reminiscent of those between cyclopropane and cyclopropanone. The entire phenomena of the C—C bond lengthening and the concomitant C—S bond shortening in the three-membered ring sulfones and sulfoxides can be accounted for in terms of the sulfur 3d-orbital participation and the variation in the donor-acceptor capacities of the S, SO and S02 . The variations of the calculated valence-state orbital energies, together with the corresponding variations of the C—C overlap populations, can be used to understand the discontinuous variations of the C—C and the C—S bond lengths in the series thiiranes -... 

Sulfones are thermally very stable compounds, diaryl derivatives being more stable than alkyl aryl sulfones which, in turn, are more stable than dialkyl sulfones allyl and benzyl substituents facilitate the homolysis by lowering the C-—S bond dissociation energy. Arylazo aryl sulfones, on heating in neutral or weakly basic media at 100 °C, yield an aryl and arenesulfonyl radical pair via a reversible one-bond fission followed by dediazoni-ation of the aryldiazenyl radical (see Scheme 2 below) °. However, photolysis provides a relatively easy method for generating sulfonyl radicals from compounds containing the SO2 moiety. 

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