Nuclear Magnetic Resonance Investigations of the Azo–Hydrazone Tautomerism of Azoreactive Dye Chromophores

✍ Scribed by Csaba Szántay; Jr; Zsuzsanna Csepregi; Péter Aranyosi; István Rusznák; László Tőke; András Víg

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 251 KB
• Volume: 35
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/(sici)1097-458x(199705)35:5<306::aid-omr93>3.0.co;2-n

✦ Synopsis

High-Ðeld 1H and 13C NMR methods (e.g. 1H{1H} and 13C{1H} NOE spectroscopy) were used to examine the tautomeric characteristics, particularly with regard to the question of azo-hydrazone tautomerism, of two azo dyes. Full 1H and 13C NMR signal assignments are given for both molecules. The NMR results indicate that in DMSO solution the tautomeric equilibria are shifted predominantly toward the hydrazone from II in both compounds. The presence of a fast interconversion could also be plausibly assumed.