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Dudkina, M.M. ; Tenkovtsev, A.V. ; Komber, H. ; Häußler, L. ; Böhme, F.
Competitive Influence of Carboxylic Groups in Ionic Complex Formation of 4-Hydroxybenzylidene Alkanones with Polyamidines

Interactions of phenolic and carboxylic group containing chromophores (hydroxyarylidenealkanones) with polyamidines were investigated by UV/vis and 1H NMR spectroscopy. Because of thestrong basicity of the polyamidines, deprotonation of the chromophores was observed. Deprotonation ofthe phenolic group is accompanied by a change of the electronic structure of the chromophore resultingin a strong bathochromic shift of the longest wavelength absorption band. Increased interactions areobserved after introduction of a carboxylic group into the chromophore. It could be shown thatdeprotonation of the carboxylic group is favored so that the deprotonation of the phenolic group onlystarts after a major part of the carboxylic groups is deprotonated. In highly diluted solutions, theinteraction of the carboxylic group with the polyamidine also increase the extent of deprotonation of thephenolic groups. A physical network formation is assumed that also increases the glass transitiontemperatures of the mixtures strongly.

Quelle
Macromolecules 37

Seiten
8389-8393

DOI
http://dx.doi.org/10.1021/ma049466i

Erschienen am
November 2004
 
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