Theoretical and NMR structural characterisation of a polymorphic azo dye

Abstract

Proton and carbon-13 NMR studies in solution and carbon-13 CP-MAS NMR in the solid state of a polymorphic azo dye derived from 2-amino-5-nitrothiazole were performed and the results are discussed and compared with theoretical data from quantum chemical calculations. The polymorphism of this compound has conformational character, two conformers coexist in CDCl 3 solution and in solid state, as shown by NMR