ISSN:
0887-624X
Keywords:
7,7′-coumarinyl polymethylene dicarboxylate
;
photopolymerization
;
fluorescence
;
coumarin
;
dimerization
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
All eight 7,7′-(4-methylcoumarinyl) polymethylene dicarboxylates (3, 4) containing terminal photoreactive coumarin chromophores show strong fluorescence intensities at room temperature in dimethyl sulfoxide (DMSO) and CH2Cl2. After irradiation with 350 nm light for 2 h, the fluorescence characteristics of the dicarboxylates reveal their photopolymerization paths. On irradiation of the unsubstituted dicarboxylates (3) in DMSO, singlet excited state excimers are formed, leading to syn head-to-head coumarin dimer configuration. However, for all dicarboxylates in CH2Cl2, the dimerization of the coumarin chromophore proceeds via a triplet excited state in the presence of benzophenone to form the anti-configuration photoproducts. Further confirmations of the reaction mechanism are made by kinetic studies. At high concentration, photopolymerization of 7,7′-(4-methylcoumarinyl) polymethylene dicarboxylate (4c) obeys zero-order and first-order kinetics for coumarin chromophore and benzophenone, respectively. This is a powerful proof of the proposed mechanism of a triplet excited state reaction. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2999-3008, 1997
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
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