Tzerpos, Nikolaos I. published the artcileDiphenylpyridylmethyl radicals. Part 1. Synthesis, dimerization and ENDOR spectroscopy of diphenyl(2-, 3- or 4-pyridyl)methyl radicals; bond dissociation enthalpies of their dimers, Formula: C6H12Br2, the publication is Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry (1995), 755-61, database is CAplus.
Ortho-ortho hydrogen van der Waals repulsions are the origin of the propeller shape of the triphenylmethyl radical and the main reason for the low bond dissociation enthalpy (BDH) of its dimer I (44.8 J mol-1). In order to reduce these steric repulsions (eliminating some aromatic hydrogens), diphenyl(2-, 3- or 4-pyridyl)methyl radicals (e.g, II) were prepared through reductive dehalogenation of the corresponding triarylchloromethanes (e.g., III) with silver in benzene. They form α,p-dimers IV–VI exclusively through the pyridine ring. ENDOR spectroscopy shows that the structure of the radicals, does not deviate substantially from that of the parent radical, Ph3C•. In contrast, the BDH values of the dimers (measured using ESR spectroscopy) show strengthening of the central C-C bond in IV (88.7 kJ mol-1) and V (90.0 kJ mol-1) and a similar value for VI (46.4 kJ mol-1) with respect to the trityl dimer I. This is a consequence of the ground state stabilization of the dimers IV–VI due to relief of strain (elimination of ring hydrogens), whereas in the case of VI, this stabilization is probably compensated by the formation of a weaker C-N bond with respect to the C-C bond. The above dimers undergo easy 1,5-H-rearrangement, autocatalyzed by the basic pyridyl groups themselves.
Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C11H24O3, Formula: C6H12Br2.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary