10.1021/om7012293
The research focuses on the synthesis, characterization, and catalytic application of tetrabenzo[a,c,g,i]fluorenyltitanium(III) and -(IV) complexes. The study involves reacting tetrabenzo[a,c,g,i]fluorenyllithium with TiCl3 to form TbfTiCl2(THF), which is then converted to TbfTiCl3 through oxidative chlorination. Further reactions with lithium phenoxides yield a series of titanium complexes, TbfTiCl2(OAr). The complexes are characterized using IR, MS, NMR measurements, and X-ray crystallography. Additionally, the article describes the synthesis of titanium complexes with TEMPO and OtBu radicals. Ethylene polymerization experiments are conducted using d-MAO as a catalyst, with the activities of the compounds reported in terms of polymer production rates and molecular weights. The reactants used include various lithium phenoxides, TEMPO, and di-tert-butylperoxide, while analyses involve melting point determination, mass spectrometry, infrared spectroscopy, and elemental analysis.
10.1016/S0040-4039(00)98115-2
The research focused on the catalytic reactions of disulfides using cobalt carbonyl, aiming to investigate the desulfurization and carbonylation of organic sulfur compounds. The study concluded that aromatic and benzylic disulfides react with carbon monoxide and a catalytic amount of cobalt carbonyl to produce thioesters and carbonyl sulfide. In the presence of t-butyl peroxide, high yields of sulfides were obtained. Key chemicals used in the process included cobalt carbonyl (Co2(CO)8), carbon monoxide (CO), and disulfides such as benzyl disulfide and phenyl disulfide, along with solvents like aqueous ethanol and benzene. The reactions resulted in the formation of thioesters and sulfides through a series of steps involving the formation of cobalt complexes and the insertion of carbon monoxide.
10.1021/jo060281e
This research investigates the impact of electronic and hydrogen bonding effects on the chain-breaking activity of sulfur-containing phenolic antioxidants. The study aims to understand the influence of sulfur substituents on the O-H bond dissociation enthalpy (BDE) and reactivity towards peroxyl radicals in phenolic antioxidants. The researchers found an inverse correlation between BDE and reactivity, with para-substituted thiyl groups decreasing BDE values to a lesser extent than methoxy groups, while ortho-substituted thiyl groups showed an opposite trend. The study concluded that sulfur-containing phenols exhibit enhanced activity as chain-breaking antioxidants compared to their oxygenated counterparts, but to a lesser extent than methoxy phenols. The research used a variety of phenols, including 2,6-di-tert-butylphenols substituted with thiyl (SR), sulfinyl (SOR), and sulfonyl (SO2R) groups, along with various solvents and reagents such as cumene, styrene, and di-tert-butyl peroxide. The findings suggest that the antioxidant efficacy of phenols para-substituted with XR groups decreases in the order X = O > S > Se, and the intramolecular hydrogen bond of the phenolic OH proton to the adjacent SMe group is weaker than that to an OMe group.
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