Metal and Ligand Effects of Photoactive Transition
Metal Carbonyls in the Iodine Degenerative Transfer Controlled Radical
Polymerization and Block Copolymerization of Vinylidene Fluoride
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Abstract
The metal and ligand effect of a
series of transition metal carbonyls
in conjunction with alkyl and perfluoroalkyl halides was investigated
in the initiation and control of the visible light, radical photopolymerizations
of vinylidene fluoride (VDF) and respectively, in the synthesis of
PVDF block copolymers. No polymerization was observed for CpMn(CO)<sub>3,</sub> CpCo(CO)<sub>2</sub>, Cp<sub>2</sub>Fe<sub>2</sub>(CO)<sub>4,</sub> Cp*<sub>2</sub>Cr<sub>2</sub>(CO)<sub>4,</sub> Mo(CO)<sub>6</sub>, Fe(CO)<sub>5,</sub> Cr(CO)<sub>6</sub>, Co<sub>2</sub>(CO)<sub>8</sub>, Co<sub>4</sub>(CO)<sub>12</sub>, Fe<sub>3</sub>(CO)<sub>12</sub>, Ru<sub>3</sub>(CO)<sub>12</sub>, (PPh<sub>3</sub>)<sub>2</sub>Ni(CO)<sub>2</sub>, Cp<sub>2</sub>Ti(CO)<sub>2</sub>, and
Au(CO)Cl. A free radical polymerization, and respectively an iodine
degenerative transfer, controlled radical polymerization was obtained
for Mn<sub>2</sub>(CO)<sub>10</sub> ∼ Re<sub>2</sub>(CO)<sub>10</sub> ≫ Cp<sub>2</sub>Mo<sub>2</sub>(CO)<sub>6</sub> ≫
Cp<sub>2</sub>W<sub>2</sub>(CO)<sub>6</sub> with CH<sub>3</sub>(CH<sub>2</sub>)<sub>5</sub>–Br, CH<sub>3</sub>(CH<sub>2</sub>)<sub>5</sub>–I, CH<sub>3</sub>–I, CCl<sub>3</sub>–Cl,
CCl<sub>3</sub>–Br, Br–(CF<sub>2</sub>)<sub>6</sub>–Br,
and respectively with CF<sub>3</sub>(CF<sub>2</sub>)<sub>3</sub>–I
and I–(CF<sub>2</sub>)<sub>4,6</sub>–I. Furthermore,
while Fe(CO)<sub>5</sub>, Cp*Cr<sub>2</sub>(CO)<sub>4</sub> and Co<sub>4</sub>(CO)<sub>12</sub> led to ∼ CF<sub>2</sub>–I
bond insertion, Re<sub>2</sub>(CO)<sub>10</sub>, Mn<sub>2</sub>(CO)<sub>10</sub>, Cp<sub>2</sub>W<sub>2</sub>(CO)<sub>6</sub>, Cp<sub>2</sub>Mo<sub>2</sub>(CO)<sub>6</sub> and Cp<sub>2</sub>Fe<sub>2</sub>(CO)<sub>4</sub> provided quantitative radical activation of both PVDF–CH<sub>2</sub>–CF<sub>2</sub>–I and PVDF–CF<sub>2</sub>–CH<sub>2</sub>–I chain ends, and were employed in
the synthesis of well-defined ABA triblock PVDF copolymers with vinyl
acetate, <i>tert</i>-butyl acrylate, methyl methacrylate,
isoprene, styrene, and acrylonitrile
