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Steric and Electronic Effects in Basic Dyes
Author(s) -
Ferguson Angus S.,
Hallas Geoffrey
Publication year - 1973
Publication title -
journal of the society of dyers and colourists
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.297
H-Index - 49
eISSN - 1478-4408
pISSN - 0037-9859
DOI - 10.1111/j.1478-4408.1973.tb03102.x
Subject(s) - steric effects , substituent , chemistry , ring (chemistry) , malachite green , electronic effect , polar effect , photochemistry , absorption (acoustics) , absorption spectroscopy , medicinal chemistry , stereochemistry , organic chemistry , materials science , physics , adsorption , quantum mechanics , composite material
Absorption spectra of several derivatives of Malachite Green containing more than one substituent in the phenyl ring have been examined. In most cases where steric effects are unimportant an additive relationship is found between the electronic effects of the substituents and the position of the first‐frequency absorption band. The presence of a second unsaturated electron‐withdrawing group in the phenyl ring leads to a further reduction in the intensity of the first band. In certain cases, the overall electron‐withdrawal is such that the equilibrium between dye‐base and univalent dye cation in acid solution is shifted in favour of the former species.