Search

The structures, energies, atomic charges, dipole moments, and vibrational spectra of methylzinc alkoxide, calculated by density functional theory methods is reported. This provides insight into the thermal reactions as well as disproportionation and ligand exchange of these clusters.

The potential energy hypersurfaces (PESs) of heptasulfer (S7) and of [LiS7](super +) are investigated by ab initio molecular orbital calculations at the G3X(MP2) level theory. It is shown that the S7 molecule like the related S6 and S8 species forms at least six isomers on the potential energy surface that are more stable than open-chain isomers.

The energies and structural properties of various isomers of the dithionous acid, H2S2O4, and of its anion, HS2O4(super - 1), were investigated via ab initio molecular orbital calculations. The hypothetical O3SSOH(super -) was identified as the lowest energy isomer for the (H,O4,S2)(super -) anion. On the other hand, the cagelike dithionous acid molecule (HO)O2SSO2(OH) was stabilized by two very strong intramolecular hydrogen bonds, and its homolytic dissociation at the SS bond has a strong endothermic nature.

Extensive ab initio calculations of (CH3)2S2, (CH3)(C3H5)S2 and-for comparison-on H2S2 (C3H5 = 3 allyl) were conducted to determine the structure and energies of thiosulfoxides during the formation of disulfanes. Ab initio molecular orbital calculations indicated the absence of thermal isomerization of HSSH to H2SS in temperatures in which H2S2 is stable. Furthermore, the alkyl derivatives exhibited high barriers to isomerization while allyl substituents form cyclic transition states.

The synthesis and characterization of dichlorotetrasulfane are described. The scheme involves the chlorination of cyclo-hexasulfur to prepare S4Cl2, which is reacted with Hg(SCN)2 to form S6(CN)2. X-ray diffraction analysis showed nonhelical chains with the terminal SCN groups in parallel orientation. S6(CN)2 was shown to undergo a new type of sulfur-transfer reaction with titanocene pentasulfide to form the monoclinic alpha-S9.

The synthesis of dicyclopentadiene polysulfanes C10H12Sn, where n = 4-8, is described. The scheme involves the use of sulfur-transfer reagents Cp2TiS5 and (Cp'TiCl)2S3, where Cp' = mu5-C5H4CH3, or Cl2 in combination with SCl derivatives of dicyclopentadiene of type C10H12(SnCl)(SmCl), where n,m = 1,2, or the dithiol of dicyclopentadiene. The 1H NMR spectra of the compounds are presented.

Diisopropoxy disulfide (C3H7OSSOC3H7) produces the chainlike radical cation H2S2O2(super . +) upon the application of 70-eV electron impact ionization in the gas phase. Neutralization-reionization mass spectroscopy neutralized the cation to give free acid HOSSOH. This molecule is stable against isomerization-dissociation processes during the 10 (super -5) second of observation.