1 H and 13 C NMR of Some α-Halo Derivatives of o -Xylene

Dibromomethyl- and bromomethyl- or bromo-substituted benzenes and naphthalenes: C-Br...Br interactions

The structures of six benzene and three naphthalene derivatives involving bromo, bromomethyl and dibromomethyl substituents, namely, 1,3-dibromo-5-(dibromomethyl)benzene, C₇H₄Br₄, 1,4-dibromo-2,5-bis(bromomethyl)benzene, C₈H₄Br₆, 1,4-dibromo-2-(dibromomethyl)benzene, C₇H₄Br₄, 1,2-bis(dibromomethyl)benzene, C₈H₆Br₄, 1-(bromomethyl)-2-(dibromomethyl)benzene, C₈H₇Br₃, 2-(bromomethyl)-3-(dibromomethyl)naphthalene, C₁₂H₉Br₃, 2,3-bis(dibromomethyl)naphthalene, C₁₂H₈Br₄, 1-(bromomethyl)-2-(dibromomethyl)naphthalene, C₁₂H₉Br₃, and 1,3-bis(dibromomethyl)benzene, C₈H₆Br₄, are presented. The packing patterns of these compounds are dominated by Br...Br contacts and C-H...Br hydrogen bonds. The Br...Br contacts, shorter than twice the van der Waals radius of bromine (3.7 Å), seem to play a crucial role in the crystal packing of all these compounds. The occurrence of Type I and Type II interactions is also discussed briefly, considering the effective atomic radius of bromine, as is their impact on the packing of molecules in the individual structures.

Conversion of Aryl Aldehydes to Benzyl Iodides and Diarylmethanes by H3PO3/I2

For the first time, H₃PO₃ was used as both the reducing reagent and the promotor in the reductive benzylation reactions with aryl aldehydes. By using a H₃PO₃/I₂ combination, various aromatic aldehydes underwent iodination reactions and Friedel-Crafts type reactions with arenes via benzyl iodide intermediates, readily producing benzyl iodides and diarylmethanes in good yields. Intramolecular cyclization reactions also took place, giving the corresponding cyclic compounds. This new strategy features easy-handling, low-cost, and metal-free conditions.

The γ-cis Effect in the Mercury-199 NMR Spectroscopy of Substituted Vinylmercury Halides

The γ- cis effect is identified for the first time in the 199Hg NMR data presented here, being proposed as a new criterion for the distinction between E and Z isomers of substituted vinylmercury compounds.