ISSN:
0170-2041
Schlagwort(e):
ET(30) values
;
Homomorphic dyes
;
Newman-Kwart rearrangement
;
Pyridinium N-thiophenoxide betaine dyes
;
Solvatochromism
;
Solvent polarity
;
Thermochromism
;
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Pyridinium N-Phenoxide Betaines and Their Application for the Characterization of Solvent Polarities, XVIII. - Synthesis and UV/Vis Spectroscopic Properties of a Negatively Solvatochromic Pyridinium N-Thiophenoxide Betaine DyeSynthesis and UV/Vis spectroscopic properties of the negatively solvatochromic, relative to 1 homomorphic, thiobetaine dye 2 are described. The new thiobetaine 2 exhibits an even larger negative solvatochromism and thermochromism than the standard betaine dye 1, which has been used to establish an empirical scale of solvent polarity, the so-called ET(30) scale. Surprisingly, there exists a linear correlation between the ETO(30) values of 1 and the ETS(30) values of 2 for both aprotic and protic solvents, despite of the fact that sulfur is usually known to act as worse hydrogen-bond acceptor than oxygen. Possible reasons for this extraordinary behaviour of 2 are discussed. In contrast to 2, the sulfo-substituted betaine dye 4 does not exhibit any solvatochromism.
Zusätzliches Material:
1 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jlac.1991199101174
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