The structures of two aldazines: [1,1′-(1E,1′E)-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)dinaphthalen-2-ol] (Lumogen) and 2,2′-(1E,1′E)-hydrazine-1,2-diylidenebis(methan-1-yl-1-ylidene)diphenol (salicylaldazine) in the solid state and in solution


Correspondence to: Dolores Santa María, Departamento de Química Orgánica y Bio-Orgánica, Facultad de Ciencias, Universidad Nacional de Educación a Distancia (UNED), Senda del Rey 9, E-28040 Madrid, Spain. E-mail:

Correspondence to: Ibon Alkorta, Instituto de Química Médica, Centro de Química Orgánica ‘Manuel Lora-Tamayo’, IQM-CSIC, Juan de la Cierva, 3, E-28006 Madrid, Spain. E-mail:


A combination of NMR spectroscopy and theoretical methods Density functional theory including dispersion corrections (DFT-D) was used to study the structures of Lumogen and salicylaldazine. In the solid state, Lumogen exists as the dihydroxy tautomer 1a (an azine, C[DOUBLE BOND]N–N[DOUBLE BOND]C) as was already known from an X-ray determination. In a deuterated dimethyl sulfoxide solution, another tautomer is observed besides 1a; its structure corresponds to the hydroxy-oxo tautomer 1b (a hydrazone, C[DOUBLE BOND]N–NH–Csp2). In what concerns salicylaldazine, we have observed only the dihydroxy tautomer 2a. Copyright © 2013 John Wiley & Sons, Ltd.