Competitive Influence of Carboxylic Groups in Ionic Complex Formation of 4-Hydroxybenzylidene Alkanones with Polyamidines

• Published in: Macromolecules Vol. 37; no. 22; pp. 8389 - 8393
• Main Authors: Dudkina, Marina M., Tenkovtsev, Andrey V., Komber, Hartmut, Häussler, Liane, Böhme, Frank
• Format: Journal Article
• Language: English; Russian
• Published: Washington, DC American Chemical Society 02.11.2004
• ISSN: 0024-9297; 1520-5835
• DOI: 10.1021/ma049466i

Interactions of phenolic and carboxylic group containing chromophores (hydroxyarylidene alkanones) with polyamidines were investigated by UV/vis and 1H NMR spectroscopy. Because of the strong basicity of the polyamidines, deprotonation of the chromophores was observed. Deprotonation of the phenolic group is accompanied by a change of the electronic structure of the chromophore resulting in a strong bathochromic shift of the longest wavelength absorption band. Increased interactions are observed after introduction of a carboxylic group into the chromophore. It could be shown that deprotonation of the carboxylic group is favored so that the deprotonation of the phenolic group only starts after a major part of the carboxylic groups is deprotonated. In highly diluted solutions, the interaction of the carboxylic group with the polyamidine also increase the extent of deprotonation of the phenolic groups. A physical network formation is assumed that also increases the glass transition temperatures of the mixtures strongly.