α,α‐Dibromotoluene as a monomer for poly (substituted methylene) synthesis: Magnesium‐mediated polycondensation of α,α‐dibromotoluene and magnesium/copper‐mediated copolycondensation of α,α‐dibromotoluene with 1,6‐dibromohexane

α,α‐Dibromotoluene 1 was found to be polymerized by the reaction with excess Mg to give poly(phenylmethylene)s 2 , whose main chains were partially dehydrogenated to carbon–carbon double bonds (C?C). The C?Cs in 2 can be brominated by treatment with Br₂. The polymerization mechanism was presumed to include the formation of Grignard reagents of various species with benzylic C? Br bonds and the nucleophilic attacks of the Grignard reagents to various compounds with benzylic C? Br bonds. Copolymerization of 1 with dichlorodimethylsilane successfully proceeded. Mg/Cu‐mediated copolycondensation of 1 with 1,6‐dibromohexane proceeded to give polymers that have similar compositions to those of random copolymers of ethylene and styrene. © 2006Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5661–5671, 2006