Aluminum Tralen Complex Meditated Reversible-Deactivation Radical Polymerization of Vinyl Acetate.

The Al III (tralen)Cl complex (tralenH 2 = N , N '-di(cyclohepta-2,4,6-trien-1-one-2-yl)-1,2-diaminobenzene) has been synthesized and applied to mediate the reversible-deactivation radical polymerization (RDRP) of vinyl monomers. The polymerization of unconjugated monomers such as vinyl acetate (VAc) and N -vinylpyrrolidone ( N VP) with Al III (tralen)Cl showed the living characters of linearly increased molecular weight with conversion and formation of block copolymer. However, the control manners in the polymerization of conjugated monomers like acrylates and styrene were limited. The electron paramagnetic resonance (EPR) spectrum indicated that Al III (tralen)BArF (BArF = tetrakis(3,5-trifluormethylphenyl)borate) and propagating radicals formed a paramagnetic dormant species, possibly PVAc-Al III (tralen)BArF, via the single-electron transfer to the tralen ligand.