Diiodo poly

Percec et al. [233-237] recently reported the synthesis of a/o-diiodo poly(vinyl chloride) (PVC) by combination of single electron transfer (SET) and degenerative chain transfer (ITP) (Scheme 42). 

Aqueous miniemulsion polymerization of styrene was performed in the presence of CeFis-I as CTA, yielding particles with a good control of the molecular weights, in contrast to emulsion polymerization where the transfer agent efficiency was low due to a slow diffusion of the hydrophobic perfluor-ohexyl iodide from the monomer droplets to the active particles during polymerization.The chains were capped with iodine as evidenced by the successful chain extension upon addition of butyl acrylate. The miniemulsion process was also successfully applied to the preparation of triblock copolymers PS-b-PDMS-b-PS starting from a telechelic diiodo-poly(dimethylsiloxane) macrotransfer agent. A somewhat similar procedure was used to prepare PVAc-b-PDMS- -PVAc triblock copolymers, but the polymerization was performed under UV irradiation (instead of thermal initiation) and in the absence of radical initiator. In this case, the aqueous dispersion medium was a key parameter to achieve a controlled polymerization (Scheme 19). ... 

The present procedure is the most convenient method for preparation of mono- or diiodo derivatives from various poly-alkylbenzenes in high yields.1 2 Thus 5-i-butyl-1,3-dimethyl-benzene gives 4-<-butyl-2,6-dimethyliodobenzene in 90% yield and 4 - - buty I -1,2 - d imet hy 1 benzene gives 5-<-butyl-2,3-dimethyl-iodobenzene in 81% yield. 5- -Butyl-l,2,3-trimethylbenzene,... 

The dibromo- (and diiodo-) stilbenes ate potentially useful monomers tor the synthesis of poly(p-phenylenevinylenes) via poly-Heck or poly-Suzuki coupling reactions. ... 

A Heck coupling reaction of l,4-diiodo-2,5-dialkoxybenzene with the bis(vinylphenyl)-substituted porphyrin 44 led to soluble and processable poly-... 

Zhao and coworkers reported the synthesis of single-chain tadpoles as shape amphiphiles. The tadpole particles were synthesized from a block copolymer precursor, containing a hydrophobic polystyrene block attached to a hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (DMAEMA) block. The DMAEMA block was collapsed using a quaternization reaction of the tertiary amine with a diiodo cross-linker. The self-assembly of these tadpole-shaped structures was then studied in various polar and non-polar solvents. These and other single-chain tadpoles represent nanoscale architectures with multiple functionalities and controlled three-dimensional structure. 

Poly(9-hexyl-3,6-carbazolyleneethynylene) (32c) has been prepared by palladium catalyzed polycondensation of 3,6-diiodo-9-hexylcarbazole (32a) and 3,6-diethynyl-9-hexyl-carbazole (32b) [172]. The polymer has a number average molecular weight of 3000. By fractionation a polymer with of 6400 has been obtained. 

Because initiation of vinyl ethers with HI/I2 yields polymers with extremely narrow poly-dispersities," " bifunctional vinyl ethers can be used in combination with HI/I2 to polymerize vinyl ethers and produce a,co-diiodo telechelics (Scheme 39). This method has been used to produce telechelics from ethyl vinyl ether, methyl vinyl ether and hexadecyl (cetyl) vinyl ether. Treatment of the living poly(ethyl vinyl ether) with mono- and di-amines yields telechelics with amino end groups (Scheme 39, equation 41). More jecently, telechelic poly(vinyl ether)s with terminal malonate or carboxy groups were synthesized using both a functional initiator and a functional terminator according to Scheme 40." ... 

Cooper prepared similar microporous poly(aryleneethynylene) (PAE) networks via Sonogashira-Hagihara cross-coupling reaction using 1,3,5-triethynyl benzene and 4,4"-diiodo-5 -(4-iodophenyl)-l,r 3, l"-terphenyl as trigonal and 1,4-diethynyl benzene and 1,4-diodo benzene as well as the corresponding biphenyl derivatives as linear... 

Poly(arylene ether sulfone)s containing perfiuorinated sulfonic acid groups were prepared by the polycondensation of 2,7-dibromo (or 2,7-diiodo)-9,9-/ /s(4-hydroxy-phenyl)fluorene with / rX4-fluorophenyl)sulfone, followed by perfiuorosulfonation via the Ullmann reaction (Scheme 4.18). 

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