ISSN:
0170-2041
Schlagwort(e):
Chromoinophores
;
Crown ethers
;
Betaine dyes
;
ET(30) values
;
Halochromism
;
Pyridinium N-phenoxide betaine dyes
;
Solvatochromism
;
Solvent polarity
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Synthesis, negative solvatochromism (Table 1, Figure 1), and negative halochromism (Tables 2-3, Figures 2-3) of the new crown ether-substituted pyridinium N-phenolate betaine dyes 3-6 are described. In contrast to other known chromoionophores, 3-5 exhibit a cation-selective negative halochromism, which manifests itself as a hypsochromic shift of the longwavelength intramolecular charge-transfer (CT) absorption band of the betaine chromophore on addition of salts. As this CT absorption band lies within the visible spectral region, the cation-induced colour change can be followed easily by eye, which suggests an application of these new chromoionophoric betaine dyes as cation indicators. The halochromism of 3-6 constitutes a new type of true halochromism, in contrast to the trivial halochromism first defined by Baeyer and Villiger in 1902.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.199319930106
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