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Halochrome Molekeln 4. Mitteilung. Chromogene Verbindungen durch Cyclisierung von [2‐(Benzothiazol‐2‐yl)amino‐4‐(diäthylamino)phenyl]heteroaryliumsalzen: Synthese und acidobasisches Verhalten
Author(s) -
Ziegler Hugo,
Balli Heinz
Publication year - 1983
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19830660728
Subject(s) - chemistry , deprotonation , protonation , medicinal chemistry , chromogenic , molecule , nuclear magnetic resonance spectroscopy , spectroscopy , resonance (particle physics) , polymer chemistry , stereochemistry , organic chemistry , ion , chromatography , physics , quantum mechanics , particle physics
Halochromic Molecules. Chromogenic Compounds by Cyclization of [2‐(Benzothiazol‐2‐yl)amino‐4‐(diethylamino)phenyl]heteroarylium Salts: Synthesis and Acidobasic Behaviour Coloured [2‐(Benzothiazol‐2‐yl)amino‐4‐(diethylamino)phenyl]heteroarylium salts are deprotonated to colourless spiro‐compounds. The preparation of these products is described and their structure is explained by 1 H‐NMR and UV/VIS spectroscopy. An investigation of the halochromic properties is carried out by spectro‐photometric determination of ε pH *‐ and εH 0 *‐curves in buffered MeOH/H 2 O solutions. p K *‐Values are determined, and the complex protonation equilibria are discussed. One of the heteroarylium salts does not form a spiro‐compound by deprotonation, but it is stabilized by a σ‐bond resonance.