Please use this identifier to cite or link to this item:
https://hdl.handle.net/10216/95739
Author(s): | Luis Cruz Petrov, V Teixeira, N Nuno Mateus Pina, F Victor de Freitas |
Title: | Establishment of the Chemical Equilibria of Different Types of Pyranoanthocyanins in Aqueous Solutions: Evidence for the Formation of Aggregation in Pyranomalvidin-3-O-coumaroylglucoside-(+)-catechin |
Issue Date: | 2010 |
Abstract: | The chemical equilibria of the pyranomalvidin-3-glucosides linked to (+)-catechin, (-)-epicatechin, and catechol moieties (and the respective coumaroylglucoside Compounds) were established by means of UV-vis spectroscopy. The conjugated double bonds among pyranic rings C and D provide a higher electronic delocalization that prevents the nucleophilic attack of water at position 2. Consequently, besides flavylium cation (AH(+)), the bases A, A(-), and A(2-) have been identified by increasing pH, and the respective acidity constants were determined by spectrophotometry. The formation of dimers at higher concentration was observed for pyranomalvidin-3-O-coumaroylglucoside-(+)-catechin, and the respective data treated by the exciton model suggests the for-nation of a chiller where the monomers form J-type aggregates with the dipolar moments in opposite directions and rotated by 174 degrees at a distance of 5.2 angstrom (from the center). |
Subject: | Espectroquímica, Química orgânica, Engenharia química Spectrochemistry, Organic chemistry, Chemical engineering |
Scientific areas: | Ciências da engenharia e tecnologias::Engenharia química Engineering and technology::Chemical engineering |
URI: | https://hdl.handle.net/10216/95739 |
Document Type: | Artigo em Revista Científica Internacional |
Rights: | restrictedAccess |
Appears in Collections: | FCUP - Artigo em Revista Científica Internacional |
Files in This Item:
File | Description | Size | Format | |
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49412.pdf Restricted Access | 1.47 MB | Adobe PDF | Request a copy from the Author(s) |
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