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Complex Formation and Flower Colors
Author(s) -
Bayer Ernst,
Egeter H.,
Fink A.,
Nether K.,
Wegmann K.
Publication year - 1966
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.196607911
Subject(s) - pigment , chemistry , base (topology) , alkali metal , delphinidin , metal , deep blue , metal ions in aqueous solution , flavonols , ion , inorganic chemistry , photochemistry , organic chemistry , polyphenol , cyanidin , mathematical analysis , mathematics , antioxidant
The pigment of the blue cornflower, protocyanin, is a complex of high molecular weight. Iron(III) and aluminum ions combine with the anhydro base of the cyanin to form deep‐blue complexes, which are stable in the physiological pH range. Complexes of this type also have been synthesized. Alkali metal salts play no part in blue flower pigments. Formation of blue complexes can be prevented by sequestration of the metal ions with stronger complexing agents, e.g. flavonols. The variation of flower colors can be explained to a large extent on the basis of the complex formation of anthocyanins. In delphinidin glycosides, the color base or anhydro base is stable even in slightly acidic media.