Organosulfur rings

Figure 45 (a) Organosulfur compounds used in organic metals (b) typical stacking motifs for organosulfur rings in organic metals... 

Thiophene, benzo[d]thiophene and dibenzo[d,organosulfur compounds formed at Rh- and Ir-mediated thiophene ring opening 97SL643. 

Block, E., Bazzi, A.A., Lambert, J.B., Wharry, S.M., Andersen, K.K., Dittmer, D.C., Patwardhan, B.H., and Smith, J.H., Carbon-13 and oxygen-17 nuclear magnetic resonance studies of organosulfur compounds the four-membered-ring-sulfone effect, J. Org. Chem., 45, 4807, 1980. 

Thiol Decomposition. As explained previously, the elimination of sulfur from benzothiophene occurs stepwise after the aromatic thiol (o-thiocresol) has formed and not in a concerted fashion from the thiophenic ring system. Extrapolation of this implies that thio-phenic sulfur in coal is eliminated by conversion to an aromatic thiol that subsequently undergoes desulfurization. Since the aromatic thiol is the apparent organosulfur species that undergoes desulfurization, it is of interest to understand the chemistry involving the elimination of sulfur from aromatic thiols. Thio-phenol was used as a model compound to examine reactions, primarily the thermal decomposition reactions that might lead to sulfur elimination. In the experiments with caustic and benzothiophene, the intermediate (o-thiocresol) most likely exists in the salt... 

Three-ring organosulfur compounds have an ionization potential (IP) that ranges around 8 eV, which is lower than that of methanol (10.85 eV), so that electron abstraction from an organosulfur compound should be favored over abstraction from methanol when an organosulfur compound is present. Thiophene and benzo[3]thiophene have an oxidation potential in excess of -I-1.8V versus NHE and are not oxidized prior to the solvent in the mixture. 

A patent for desulfurization of petroleum streams containing condensed ring heterocyclic organosulfur compounds on the basis of the similar principle was filed by Research and Engineering Company in 2001.58... 

In early work on organosulfur compounds, Duess (I) and Hil-ditch (2) reported the preparation of various aromatic disulfides by condensation reactions of thiophenol on treatment with aluminum chloride and sulfuric acid, respectively. Macallum (3) was the first to report the preparation of a phenylene sulfide polymer. His procedure involved the reaction of sulfur, sodium carbonate, and dichlorobenzene in a sealed vessel. Polymers made by this scheme generally have more than one sulfur atom between benzene rings, as indicated by the structure —( C6H4S )w-. 

Thiannulation is used here to designate the formation of a heterosulfur ring from an organosulfur precursor. It may result from the intermolecular condensation of two or more precursors, one bearing the requisite sulfur atom in an acyclic structure. Alternatively, it may involve an intramolecular cyclization. By contrast, sulfur bridging involves inorganic sulfur as the source of the heteroatom. 

The photochemistry of organosulfur compounds in general has been the subject both of annual reports [1,2] and of timely scattered reviews [3-5], Light-induced reactions of specific chromophores, such as sulfoxides and sulfones [6], thiocarbonyl compounds [7], and thiols [8] have been discussed in more detail, as has the photochemistry of thiophenes and certain other specific ring systems [9,10],... 

The dominant theme since the mid-1980s in the chemistry of thiophenes has undoubtedly been the application of transition metal catalysis. There are two distinct aspects of this work the first is the use of Pd or Ni as catalysts for bond formation. The other is the study of transition metal-mediated ring opening of thiophene by cleavage of S—C bonds. The former is discussed in Section 2.10.4.7. In addition, some mechanistically interesting results have also been reported during this period. These include the preparation of the first fully characterized, stable pentacoordinated sulfur compound with four C—S bonds (Section 2.10.3.1) and the first clear evidence for an organosulfur ate complex (Section 2.10.2.6.4). 

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