Self-assembly of T-shape 2H-benzo[d][1,2,3]-triazoles. Optical waveguide and photophysical properties

Torres, I.; Carrillo, J. R.; Díaz-Ortiz, A.; Martín, R.; Gómez, M. V.; Stegemann, L.; Strassert, C. A.; Orduna, J.; Buendía, J.; Greciano, E. E.; Valera, J. S.; Matesanz, E.; Sánchez, L.; Prieto, P.

Abstract

T-Shaped 2H-benzo[d][1{,}2{,}3]triazole derivatives have been synthesized by Sonogashira coupling reactions under microwave irradiation. DFT calculations were performed in order to understand the structure–property relationships – an aspect that is of vital importance for the rational design of organic self-assemblies for optoelectronic applications. Concentration-dependent 1H Pulse Field-Gradient Spin-Echo (PFGSE) NMR spectroscopy and UV/Vis spectrophotometry indicated the absence of a tendency for the aggregation of single molecules in solution. In contrast{,} in the solid state these compounds form organized aggregates and these were studied by scanning electron microscopy (SEM){,} which showed the influence that the peripheral substitution has on the morphology of the aggregates. For example{,} methoxy-substituted benzotriazoles self-assemble into thick and crystalline needle-like structures. However{,} the unsubstituted triazoles give rise to flower-like aggregates. Interestingly{,} the aggregates formed by benzotriazole 1c exhibit waveguide properties.