Sulfur-nitrogen bonds, dissociation energies

Table 2. Bond dissociation energies of alkenes, alkynes, and aromatics Table 3. Bond dissociation energies of C/H/O compounds Table 4. Bond dissociation energies of sulfur-containing compounds Table 5. Bond dissociation energies of nitrogen-containing compounds Table 6. Bond dissociation of halocarbons...

Thiazyl monomer is a radical with one unpaired electron. In contrast to nitric oxide, it polymerizes so readily that it cannot be isolated as a monomeric solid or liquid and has only a transient existence in the gas phase. Thiazyl monomer may be generated in a number of ways, including the volatilization of (SN) c (2) or pyrolysis of S4N4 (1) over quartz wool above 300 °C. The emission spectrum and ESR spectrum have been reported. The bond length is calculated to be 149.7 pm from its spectroscopic moment of inertia. This indicates a bond order of between two and three. The dissociation energy of this strong sulfur-nitrogen bond is estimated to be 463 kj mol from spectroscopic data. Nevertheless, like other sulfur nitrides, NS is endothermic and unstable with respect to its elements. Thiazyl monomer exhibits an IR band at 1209 cm T The experimental dipole moment is 1.83 0.03 D and the ionization potential is 9.85 eV. 

This review article contains "best" values of bond-dissociation energies at 298.15 K of hydrocarbons and their nitrogen, oxygen, sulfur, halogen, and silicon derivatives. There is also some limited data on inorganic molecules. 

We have tried to increase the reactivity of modified polystyrene by introducing sulphur bonds with small dissociation energy into its macromolecules. For that purpose we carried out styrene polymerization with tetramethylthiuram disulphide in the presence of sulfur as an initiator. The chemical composition of modified polystyrene was as follows 83.02% C, 7.28% H, 1.07% N, 7.91% S (Table 1). As acconsequence of the addition of sulfur to the reaction medium the sulfur/nitrogen mole ratio increased from 2 1 to above 3 1. The average molecula weight of po lystyrene modified by thiuram and sulfur was low, Mv = 2030 and = 2080. 

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