Iodobenzene, polymer-based

Polymer-based iodobenzene difluoride 1,1-Difluorides from ethylene derivs. 

Methylbenzoate was obtained from iodobenzene in moderate to good yield with polymer-stabilised palladium nanoparticles as the catalyst.1391 Of the ionic liquids screened in the reaction, those based on the pyridinium cation generally gave better results than imidazolium-type liquids. The latter probably deactivate the catalyst by formation of stable carbene complexes. 

Our work on latent biphasic systems has focused on linear polymers [165]. Initially these studies focused on poly(JV-alkylacrylamide)s like PNODAM because we had earlier shown that these lipophilic materials are very phase-selectively soluble in heptane [158,165]. This initial work used the PNODAM-bound SCS-Pd catalyst 116 in a DMA-heptane mixture with iodobenzene and acrylic acid as substrates and triethylamine as a base. This catalyst mixture was initially homogeneous at 25 On heating, Heck chemistry occurred to form cinnamic acid. Subsequent cooling of this reaction mixture formed a biphasic mixture even without addition of water because the reaction had formed some triethyl ammonium iodide, and this ammonium salt functioned as the perturbant. 

Supported catalysts involving palladium on carbon and dendrimer-encapsulated palladium and a polymer-supported phosphine palladium catalyst have facilitated C-C coupling reactions in SCCO2. Polymer-tethered substrates or amine bases have also been successfully used for the Mizoroki-Heck and Suzuki-Miyaura reactions in SCCO2. For example, REM resin underwent a Mizoroki-Heck reaction with iodobenzene to yield, after cleavage, ( )-methyl cinnamate 48 (74%) (Scheme 88). It is assumed that SCCO2 acts as a good solvent that swells the polymers and exposes reactive sites. 

In 1999, Stone et al. [84] proposed a PEMFC based on phosphonic acid trifluorostyrene. Polymers were prepared in two basic steps (Fig. 2.17) (i) the synthesis of 4-iodobenzene phosphonic acid dimethyl ester (4-1) and (ii) the synthesis of the p-dimethyl phosphonate-a,, -trifluorostyrene (4-2). The authors showed that the monomer either homopolymerized or copolymerized (Fig. 2.17). Although it is known that a,/ ,/ -trifluorostyrene does not homopolymerize under radical conditions. 

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