Poly -boronate ester polymers

Sold polyme electrolyte (SPE) based on branched poly(ethylene glycol) (PEG)-boronate ester polymers... 

In the second method, the alkoxyamine-ftmctionalized backbone is prepared by a chemical modification of a preformed polymer. Abbasian and Entezami prepared alkoxyamine-functionalized poly(vinyl chloride) (PVC) in a three-step procedure. PVC was first arylated with toluene by Friedel-Crafts acylation followed by a bromination step using N-bromosuccinimide. The bromine atom was finally reacted via nucleophilic substitution by the TEMPO hydro-xylamine anion. PVC-g-PS was finally obtained after TEMPO-mediated polymerization of styrene. A TEMPO-functionalized isotactic poly(l-butene) macroinitiator was synthesized by Jo et al. who used a rhodium-catalyzed activation of the alkane C-H bonds and subsequent transformations of the boronate ester group into an hydroxyl pendant group. This reactive moiety was then used to attach a TEMPO-based alkoxyamine bearing another hydroxy function by an ether linkage. A method to prepare PE-g-PS from a poly(ethylene-co-m,p--methylstyrene) obtained by metallocene-catalyzed polymerization was also reported. The macroalkoxya-mine was synthesized after bromination with N-bromosuccinimide followed by a nucleophilic reaction with the TEMPO hydroxylamine anion. 

Growing from simple polymeric assemblies, more complex structures arise from the interactions between polyvalent boronic acids interacting with poly-functional diols. These products may be dynamic, highly cross-linked polymer networks, analogous to slime. Alternatively, these assemblies have taken the form of highly ordered frameworks with persistent pores. Regardless of the degree of order inherent in these systems, the key assembly motif still relies on boronate ester formation. 

Scheme 4 shows the synthesis of poly(/7-arylenevinylene)-type (PAV-type) jT-stacked polymer by Heck-Mizoroki cross-coupling [24, 25]. The treatment of pseudo-/7ara-divinyl[2.2]paracyclophane 14 with diiodofluorene 15 using a Pd(OAc)2/P(o-Tol)3/NBu3 catalytic system afforded the corresponding stacked polymer 16 in 96 % isolated yield with M =5,200 [26]. Poly(/7-arylene)-type (PA-type) jc-stacked polymers were prepared by Suzuki-Miyaura cross-coupling [27, 28], and a representative example is shown in Scheme 5. The Pd(PPh3)4-catalyzed polymerization of monomer 9 with bis(boronic acid ester) monomer 17 afforded the polymer 18 in 89 % isolated yield (Mn=2,600) [29].

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