The electronic structures and bonding interactions in the syn and anti isomers of Mo₂S₄(edt)₂²⁻ (edt = ethanedithiolato, (SCH₂CH₂S)²⁻) were examined and compared through Fenske-Hall and extended Huckel molecular orbital calculations. The electronic structures of a hypothetical closed isomer and the fragment MoS₃(edt)³⁻ were calculated as well. A molybdenum-molybdenum bonding interaction accounts for the diamagnetism of the complexes and is important in determining the relative stabilities of the isomers (syn > closed > anti). The structure of the syn isomer of (P(C₆H₅)₄)₂W₂S₄(edt)₂ was determined by X-ray crystallography. The compound crystallizes in the space group P2₁/n with a = 16.126(7)A, b = 25.03(1)A, c = 13.021(6)A, β = 101.73(4)°, and Z = 4. The calculated and observed densities are 1.755 and 1.757 g cm⁻³. Full-matrix least squares refinement of the 7414 data with Fₒ² > 3σ(Fₒ²) gave R = 0.039 and R(w) = 0.046. Each tungsten atom is ligated by five sulfur atoms in approximate tetragonal-pyramidal geometry. The W-W distance is 2.862(1)A, indicating a metal-metal bond. The average W-S(terminal) distance is 2.144(2)A, the average W-S(bridging) is 2.328(2)A, and the average W-S(edt) distance is 2.404(2)A. A variety of sulfur compounds, including hydrogen sulfide, aromatic and aliphatic thiols, cysteine, and bisulfite reduced MoO(TTP)OR, oxoalkoxotetratolylporphinatomolybdenum(V) (R = H, CH₃, C₂H₅, C₅H₁₁, MoO(TTP)), to the corresponding Mo(IV) species, MoO(TTP). The kinetics of the redox reaction between MoO(TTP)OC₂H₅ and RSH (R = C₂H₅, C₆H₅) were monitored at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))(RSH), with k₂ = 8.0 x 10⁻¹³ M⁻¹sec⁻¹ for C₂H₅SH and k₂ = 8.2 M⁻¹sec⁻¹ for C₆H₅SH describes the kinetic data. Sulfur compounds also reduced MoO₂(TTP). The kinetics of the redox reaction of the novel compound MoO(TTP)HSO₃ were monitored in chloroform solution at ambient temperature. The rate law d(Mo(IV))/dt = k₂(Mo(V))² with k₂ = 3.4 x 10² M⁻¹sec⁻¹ describes the kinetic data. Oxidation of MoO(TTP) to Mo(V) occurs in the presence of air. Oxidation catalysis by oxomolybdenum porphyrins was demonstrated for the substrates C₂H₅SH, C₆H₅SH, and HSO₃⁻. Mechanisms for these reactions are proposed.

No description available.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xxiii, 236 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 220-236).

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references. Also available in print.

Thesis--St. Catharine's College, Cambridge. / Typescript (carbon) with ms. corrections. Without thesis statement. Appendices 1-3 by N. Sheppard and G.B.B.M. Sutherland. Bibliography: leaves 209-216.

Includes bibliographical references.

Cp$ sb2$Ti(C))$ sb2$, where Cp = $ eta sp5$-cyclopentadienyl, reacted with RSSSR to give the catenated sulfur complexes Cp$ sb2$Ti(SR)(SSR), where R = CMe$ sb3$, CHMe$ sb2$, CH$ sb2$Ph, p-C$ sb6$H$ sb4$Me and CPh$ sb3$. These complexes, except for R = CPh$ sb3$, reacted with PhCH$ sb2$Br to give Cp$ sb2$TiBr$ sb2$, PhCH$ sb2$SR and PhCH$ sb2$SSR as major products. Cp$ sb2$Ti(SR)(SSR) desulfurized slowly in solution and rapidly in the presence of Ph$ sb3$P, giving Cp$ sb2$Ti(SR)$ sb2$ and Ph$ sb3$PS, in addition to other species. Similarly, phth-SSR, where phth = phthalimide, oxidatively added to Cp$ sb2$Ti(CO)$ sb2$ to give Cp$ sb2$Ti(X)(SSR), where X = phth and R = CMe$ sb3$, CHMe$ sb2$, CH$ sb2$Ph and p-C$ sb6$H$ sb4$Me. Solvolysis by MeOH and EtOH gave the species where X = OMe and OEt. In a similar manner Ph$ sb3$CSSCl added to Cp$ sb2$Ti(CO)$ sb2$ to give Cp$ sb2$Ti(Cl)(SSCPh$ sb3$). Treatment of Cp$ sb2$Ti(SR)(SSR) with (norbornadiene)Mo(CO)$ sb4$ gave the bridged dimers, (Cp$ sb2$Ti($ mu$-SR)-($ mu$-S$ sb{ rm x}$R)Mo(CO)$ sb4$), where x = 1 and 2 and R = CMe$ sb3$ and CHMe$ sb2$. The complexes where x = 2 contained the rare iso-$ mu$-$ eta sp1$-SSR ligand. In solution at low temperatures the bridging thiolato and disulfano groups were predominantly transoid. At higher temperatures, a dynamic process that allowed averaging of cyclopentadienyl ring environments took place. $ sp1$H NMR studies permitted evaluation of $ Delta{ rm G sbsp{c}{ ddagger}}$ for the averaging process.

No description available.

Reevaluation of organosulfur heats of formation resulted in the conclusion that the sulfur-sulfur bond of aliphatic disulfides is nearly 15 Kcal/mole stronger than the disulfide carbon-sulfur bond energy. Semi-empirical calculations using AM1, MNDO and MINDO/3 from the AMPAC program package confirmed these results and clarified their relative impact on organosulfide and disulfide properties. / Existing organoselenium bond energy data were also reevaluated and erroneous assumptions discovered. New bond energy estimates were made via a new procedure. It was concluded that the selenium-selenium bond is also stronger than the selenium-carbon of aliphatic diselenides. / The above results led to the conclusion that loss of molecular dichalcogen from molecules such as disulfides or diselenides is favored over the stepwise loss of a single chalcogen by about 40 Kcal/mol. Loss of molecular diselenium from dibenzyl diselenide is reported. The average carbon-selenium bond energy of the latter is calculated to be only 27 Kcal/mol. / The preparation of 2-thiatriselenides (RSeSSeR) and 2,3-dithiatetraselenides (RSeSSSeR) has been achieved from selenosilanes. The products were characterized by $ sp{77}$Se NMR and the trends of chemical shifts were analyzed. / The preparation of the first selenium transfer reagents, including the first unsymmetrical chalcogen transfer reagent, is reported. Their use to effect the synthesis of 2-selenatrisulfides (RSSeSR) is also reported. Low temperature $ sp{77}$Se NMR was used to elucidate the reaction mechanism and characterize several intermediates such as selenuranes, selenonium ions and azole selenides. In addition, 2,3-diselenatetrasulfides (RSSeSeSR) were characterized by $ sp{77}$Se NMR.

Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2005. / Davis, Douglas, Committee Member ; Huey, Greg, Committee Member ; Nenes, Athanasios, Committee Member ; Weber, Rodney, Committee Member ; Whetten, Robert, Committee Member ; Wine, Paul H., Committee Chair. Includes bibliographical references.