Noncovalent binding of the halogens to aromatic donors. Discrete structures of labile Br2 complexes with benzene and toluene

Precise molecular structures resulting from the noncovalent interaction of Br2 with benzene (and toluene) reveal the unusual localized bonding to specific (one or two) carbon centers in prereactive complexes leading directly to the transition states for electrophilic aromatic brominations.