Amongst functional macromolecules, the combination of polymers and dyes is a research field of great potential with regard to high-performance materials. Accordingly, colored polymers have become increasingly important as materials for miscellaneous technical applications in recent years while also being a major part of everyday life. For instance, dye-containing polymers are nowadays widely applied in medicine, painting industries, analytics and gas separation processes. Since these applications are obviously connected to the dye's nature, which is incorporated into the corresponding polymers, the affinity of certain polymers to dyes is exploited in wastewater work-ups after (textile) dyeing procedures. In this review, we wish to point out the great importance of dye-containing polymers, with a comprehensive scope and a focus on azo, triphenylmethane, indigoid, perylene and anthraquinone dyes. Since a large number of synthetic approaches towards the preparation of such materials can be found in the literature, an elaborated overview of different preparation techniques is given as well.
SummaryThe double alkylation of N-vinylpyrrolidone (N-VP) with 1,8-dibromooctane yields paraffin-like oligomeric chains bearing polymerizable vinyl moieties. These oligomers were radically crosslinked in bulk with N-VP as co-monomer yielding swellable polymer disks. The vinylic side groups of the N-VP oligomers allow thiol–ene click reactions with 2-aminoethanethiol hydrochloride to obtain reactive amino-functionalized oligomers. Further modification of the free amino groups with 1,4-difluoro-9,10-anthraquinone (DFA) yields red-colored oligomeric anthraquinone dyes. The final reaction of DFA-substituted N-VP oligomers with Jeffamine® M 600 leads to blue-colored and branched oligomers with poly(ethylene glycol) side chains.
Two novel cyclodextrin-modified anthraquinone dyes were synthesized and investigated for their complexation behaviour and formation of superstructures. Therefore, 1-fluoro-4-N-(propargylamino)anthraquinone and 1,4-bis(propargyloxy)anthraquinone were prepared via nucleophilic aromatic displacement and subsequently covalently 'click-coupled' in a copper(I)-catalysed azide-alkyne cycloaddition with -cyclodextrin monoazide. Both the propargyl-modified precursor and the click-coupled anthraquinone dyes were evaluated as hosts and guests, respectively, in -cyclodextrin interactions. The anthraquinone dye bearing two cyclodextrins, compound 1-fluoro-4-(((1--cyclodextrin-1H-1,2,3-triazol-5-yl)methyl)amino)anthraquinone can be supramolecularly linked to 11 resulting in coloured polymers. These features of -cyclodextrin-linked anthraquinone dyes can be verified with either 1 H 1 H NMR rotating frame nuclear Overhauser effect spectroscopy or the naked eye.
1,4-bis((1--cyclodextrin-1H-1,2,3-triazol-5-yl)methoxy)anthraquinone, enables the reversible formation of supramolecular crosslinked poly[(N,N-dimethyl acrylamide)-co-(N-(ferrocenoylmethyl)acrylamide)] (11), whereas the monofunctionalized
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