33284-53-6Relevant academic research and scientific papers
Photochemical reactions of [(η5-C5R5)Re(CO)3] (R = Me or H) with aryl halides in benzene: Stoichiometric formation of biphenyl
Zhu, Bolin,Huang, Xinwei,Hao, Xiaoting
, p. 5932 - 5939 (2015/02/18)
Photolysis of [Cp ??Re(CO)3] (Cp? = η5-C5Me5) with bromobenzene or chlorobenzene in benzene results in biphenyl and the corresponding rhenium hydride halide complex trans-[Cp?Re(CO)2H(X)], which further converts into the dihalide complexes cis/trans-[Cp?Re(CO)2X2] (X = Br, Cl). Additional experiments, including isotopic labeling experiments, indicate that one phenyl ring in biphenyl comes from the aryl halide and the other one comes from solvent benzene. Photolysis of [CpRe(CO)3] (Cp = η5-C5H5) with aryl halide in benzene similarly generates biphenyl, the corresponding rhenium hydride halide complex. Furthermore, the reaction also affords small amounts of rhenium dihydride complex [CpRe(CO)2H2]. Plausible mechanisms for the formation of the different types of products are proposed that involve intermolecular C-X and C-H activation. Molecular structures of trans-[Cp?Re(CO)2(Br)(Cl)] (trans-6) and trans-[CpRe(CO)2(Br)(Cl)] (trans-12) determined by X-ray diffraction are also presented.
Polychlorinated biphenyl reductive dechlorination by vitamin B12s: Thermodynamics and regiospecificity
Woods, Sandra L.,Trobaugh, Darin J.,Carter, Kim J.
, p. 857 - 863 (2007/10/03)
Microbial reductive dechlorination reactions play an important role in determining the environmental fate of polychlorinated biphenyls (PCBs), especially for PCB congeners with more than four chlorines. Powerful chemical catalysts such as vitamin B12s provide an effective tool for the study of reductive dechlorination reactions. The reductive dechlorination of PCBs by titanium(III) citrate-reduced vitamin B12s was studied in batch reactors. Long-term experiments demonstrated reductive dechlorination of aqueous and sediment-sorbed 2,3,4,5,6-pentachlorobiphenyl (2,3,4,5,6-PeCB) to tetra-, tri-, di-, and monochlorobiphenyl products. Approximately 10% chlorine removal was observed in 36 days in aqueous experiments at 20°C; the sediment experiment showed 40% chlorine removal in 42 days at 30°C. Nearly all possible intermediates were produced and reductively dechlorinated, with no apparent accumulation of individual congeners. Short-term experiments were conducted to determine the pathway forvitamin B12s-catalyzed reductive dechlorination of aqueous 2,3,4,5,6-PeCB and its dechlorinated products; relative product distributions were measured for all possible tetra-and trichlorobiphenyl reductive dechlorination reactions. Theoretical product distributions based on free energies of formation agreed with observed product distributions for short-and long-term experiments. Reductive dechlorination was favored at positions with adjacent chlorines; on average, chlorines were removed equally from ortho, meta, and para positions.
Physical, spectral and chromatographic properties of all 209 individual PCB congeners
Bolgar,et al.
, p. 2687 - 2705 (2007/10/03)
Through the use of two capillary GC columns: 40% octadecyl/ 15% phenyl methyl siloxane and 50% phenyl methyl siloxane, it was possible to separate 201 PCB congeners with only four unresolved pairs. The data compiled in this study for all 209 congeners will aid in the identification of selected individual components of these environmental pollutants. The use of this data also presents the opportunity for the improved quantification of the commercial PCB formulations. -from Authors
Annelations with Tetrachlorothiophene 1,1-Dioxide
Raasch, Maynard S.
, p. 856 - 867 (2007/10/02)
Tetrachlorothiophene 1,1-dioxide is a reactive, cheletropic Diels-Alder reagent.It has been used to annelate, with loss of sulfur dioxide, a large variety of olefinic compounds to form 1,2,3,4-tetrachloro-1,3-cyclohexadiene derivatives.Dehydrochlorination of these forms 1,2,4-trichloro aromatic compounds.Both double bonds in thiophene and N-methylpyrrole are annelated.Addition of tetrachlorothiophene dioxide to acyclic 1,5-dienes, which may contain a heteroatom, provides a facile synthesis of tetrachloroisotwistenes (51) and heteroisotwistenes (56) by a double Diels-Alder reaction.Acyclic 1,6-dienes lead to tetrachlorohomoisotwistene (59) and heterohomoisotwistenes (61).By use of 1,5-cyclooctadiene, sym-dibenzocyclooctatetraene, and 1,5-cyclononadiene, the more complex carbocycles 62, 65, and 66 are generated.Tetrabromothiophene dioxide reacts like the tetrachloro compound.
