G. C. Bailey, T. Swager
Mar 18, 2006
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0
Influential Citations
30
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Journal
Macromolecules
Abstract
Poly(phenyleneethynylene)s (PPEs) capable of reacting with thiol-containing molecules have been designed and synthesized with number-average molecular weights ranging from 8000 to 11 000. The PPEs contain pendent masked maleimide units available to participate in conjugate additions and Diels−Alder chemistries after being thermally activated. If the maleimide group is left unmasked during palladium-catalyzed cross-coupling polymerization, it leads to side reactions and the production only of short chain oligomers (Mn < 3000, DP ∼ 4). Reversible Diels−Alder reactions between the maleimides and furan were determined to be a very effective method to produce a masked Michael acceptor that can be unveiled after polymerization under relatively mild thermal conditions. Cycloreversion to the maleimide has been monitored by thermogravimetric analysis (TGA), TGA-MS, IR, and NMR. A PPE containing the masked maleimide unit has been modified with a thiolated carboxy-X-rhodamine (ROX) dye, and the resulting absorbance ...