The pyrene-based atom transfer radical polymerization (ATRP) initiator of 1-pyrenemethyl 2-bromoisobutyrate (PMBriB) was applied to the photo-induced radical polymerization of methyl acrylate, methyl methacrylate, and styrene. During the polymerization, the fluorescence of the polymer solution caused by the chain end pyrene group was observed to be slightly enhanced in all cases, possibly due to the decline of the aggregation caused quenching (ACQ) effect. However, the fluorescence of polystyrene obtained from photo-induced ATRP was significantly increased. Differential scanning calorimeter (DSC) meas-urements, NMR spectroscopy, and fluorescence measurements associated with a series of control studies demonstrated that the enhanced fluorescence was a persistent phenomenon in both solution and the solid state but the polystyrenes with and without enhanced fluorescence showed no observable difference in chemical bonding and molecular conformation. At this stage, the coexistence of pyrene, 2-bromoisobutyrate group, styrene, and light was required for this novel phenomenon and the mechanism of this fluorescence enhancement is still being studied.[a] C.
Poly(di(pyridin‐2‐yl)methyl acrylate) (PDPyMA), which was obtained by the free radical polymerization of designed coordinative monomer of di(pyridin‐2‐yl)methyl acrylate, is able to coordinate with various metal ions to form heterogeneous catalysts for diverse catalytic reactions. The Pd and Cu complexes supported by PDPyMA were developed for the heterogeneous Suzuki‐Miyaura reaction and Friedel‐Crafts alkylation, respectively. The PDPyMA‐based catalysts showed no significant decline of reactivity after five times recycling. However, the hydrolysis of the PDPyMA backbone under alkaline conditions limited the catalytic efficiency of this heterogeneous catalyst so that the coordinative monomer was redesigned as 1,1‐di(pyridine‐2‐yl)‐2‐(4‐vinylphenyl)ethan‐1‐ol and then 2,2′‐(1‐methoxy‐2‐(4‐vinylphenyl)ethane‐1,1‐diyl)dipyridine (MVPhDPy). With copolymerization of N‐isopropyl acrylamide (NIPAM), the efficiency of polymer‐based heterogeneous catalysts could be further raised, demonstrated by the increased turn over number in the Suzuki‐Miyaura reaction, which approached 5,260 by using the catalyst formed from poly(MVPhDPy‐co‐NIPAM) and Pd(OAc)2. poly(MVPhDPy‐co‐NIPAM) copolymer, therefore, could be a versatile platform to support different metal ions for various heterogeneous catalytic reactions.
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