Post-Polymerization Functionalization Approach for Highly Water-Soluble Well-Defined Regioregular Head-to-Tail Glycopolythiophenes

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• 作者：Cuihua Xue ; Fen-Tair Luo ; Haiying Liu
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：September 18, 2007
• 年：2007
• 卷：40
• 期：19
• 页码：6863 - 6870
• 全文大小：257K
• 年卷期：v.40,no.19(September 18, 2007)
• ISSN：1520-5835

文摘

Two bromide-bearing regioregular head-to-tail polythiophenes (polymers 1 and 3) were preparedby using Grignard metathesis method to polymerize 2,5-dibromo-3-bromohexylthiophene (2) and 2,5-dibromo-3-(11-bromo-3,6,9-trioxa-1-undecoxy)thiophene (7), respectively. Well-defined regioregular head-to-tail glycopolythiophenes were prepared through post-polymerization functionalization approach by treating the bromide-bearing polythiophenes with 1-thiolethyl--D-mannose tetraacetate (3a) or 1-thiol--D-glucose tetraacetrate (3b)in THF solution with a basic condition, respectively, and followed by sequential deacetylation under Zemplénconditions in methanol and methylene chloride containing sodium methoxide at room temperature. Glycopolythiophenes (polymers C and D) with hydrophilic tetra(ethylene glycol) as tethered spacers between the polymerbackbone and carbohydrate residues are highly water-soluble while glycopolythiophenes (polymers A and B)with hydrophobic hexyl tethered spacers are completely insoluble in water. All polythiophenes display lowfluorescence with fluorescent quantum yield ranging from 0.4% to 3%. However, water-soluble polymers C andD in 0.1 M phosphate buffer (pH 7.2) show a little higher fluorescent intensity than their precursor polymer 3 inchloroform solution. -Mannose-bearing glycopolythiophene (polymer C) exhibits specific binding to ConcanavalinA through multivalent interactions with a binding constant of 2.15 × 10⁵.