Engineering organic semiconducting solids. Multicomponent access to crystalline 3-(4-aryl-1,2,3-triazolyl)coumarins

Abstract

Crystalline 3-(4-aryl-1,2,3-triazol-1-yl)coumarins (ATCs) were prepared from commercial materials using a four-component methodology as a key step. In the present work, a feasible and environmentally friendly route to the title compounds was developed through the reaction between salicylaldehydes, ethyl bromoacetate, phenylacetylenes and sodium azide under mild conditions, with short reaction times and a simple workup. Crystalline solids are readily accessed from the featured products via solution processing and their arrays in the solid state were elucidated through SXRD; these molecules display a periodic overlap of π-systems, which facilitates carrier transport in organic electronic devices. Semiconductor band gaps for the obtained solids were derived through plane-wave DFT and compared with reference systems known to display superior performance in organic electronics. Thus ATCs represent attractive systems for research and implementation in molecular materials, a task which will be facilitated by the concise route herein described.

3-(4-Formylphenyl)-triazole functionalized coumarins as violet-blue luminophores and n-type semiconductors: synthesis, photophysical, electrochemical and thermal properties

“…The structures of 1a–g were optimized by DFT B3LYP/6-31G (d, p) level of theory in CH 2 Cl 2 . The computed geometry predicts an almost planar molecular structures with torsion angles near to 0° between triazole and coumarin, and FPh and triazole rings, in contrast with the measured values in analogous molecules (5.8–21.5°, T–C; and 1.6–18.1°, FPh-T), 27 a complete list of calculated torsion angles is in Table S2. † The theoretical absorption spectra of 1a–g, obtained with BhandHLYP/6-31G (d, p), CPCM model in CH 2 Cl 2 , are in good correspondence with the experimental ones, Fig.…”

“…This effect can be explained as the consequence of a fixed non-coplanar conformation between the two partners in the crystal network, in agreement with our previous study where the torsion angle between FPhT and coumarin fluorophores are in the 5.8–21.5° range. 27 Even though, the E g-opt values of 1a–g are between 2.63 to 3.17 eV, slightly smaller than in solution. Furthermore, the λ em maxima are red-shifted for all compounds, Fig.…”

“…A four-component one pot methodology reported elsewhere was followed, 27 starting from the corresponding salicylaldehydes, ethyl bromoacetate, 4-ethynylbenzaldehyde and sodium azide under mild conditions, but using CuCN (10% equiv.) as catalyst instead of CuI.…”

“…25,26 Recently, our group has also reported the uorescent properties of 3-phenyl-triazolyl-coumarins in the context of crystal engineering. 27 Nevertheless, it is known that electron-donor (ED) substituents on C-7 and electron-withdrawing (EW) substituents on C-3 lead to push-pull systems in the coumarin structural unit, inducing a strong polarization that allows tuning their absorption-emission proles. 28 In addition, SO conjugates of triazole (T) and coumarin (C) moieties are also known to possess improved optical properties tuned by the position and nature of the coumarin substituents.…”

Síntesis de cumarinas fluorescentes

“…Recientemente, en nuestro grupo de trabajo hemos desarrollado una metodología multicomponente aplicable a una gran variedad de sustratos, que permite la preparación de 3-(4-aril-1,2,3triazolil)cumarinas en un solo paso con propiedades de semiconductores en estado sólido. Estos compuestos pueden ser empleados como capa activa en dispositivos optoelectrónicos, por lo que son excelentes candidatos para el desarrollo de materiales orgánicos [11]. Continuando con estos estudios, en este trabajo se presenta la síntesis y la caracterización de derivados de cumarinas que incorporan un anillo de benzoxazol a fin de tener nuevos sistemas que presenten un incremento en la conjugación π en la estructura del fluoroforo [8], logrando valores del band gap óptico pequeños que indican la posibilidad de que estos compuestos puedan tener propiedades de semiconductores.…”