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

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 H 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.Financial support from the MINECO of Spain (projects CTQ2012-35692 and CTQ2014-52331-R), Junta de Comunidades de Castilla-La Mancha (FEDER funded project PEII-2014-002-A), and DFG (SFG-TRR 61, project C07) is gratefully acknowledged. I. Torres and R. Martin are indebted to MEC for a FPU studentship. M. V. G. thanks the MINECO of Spain for funding her contract through the Ramon y Cajal program and Parque Cientifico y Tecnologico de Castilla-La Mancha.Peer Reviewe