Synthesis of Photochromic Oligophenylenimines: Optical and Computational Studies, Armando I. Martínez Pérez, Oscar Coreño Alonso, Julián Cruz Borbolla, José M. Vásquez-Pérez, Juan Coreño Alonso, Karina Alemán Ayala, Gabriel Luna-Bárcenas, Thangarasu Pandiyan and Rosa A. Vázquez García, Molecules, 20 (4) (2015), 5440-5455; doi:10.3390/molecules20045440
Phenyleneimine oligomers 4,4'-(((1E,1'E)-(((1E,1'E)-(1,4-phenylenebis-(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-4,1-phenylene))bis(methanylyl-idene))-bis(azanylylidene))dianiline (OIC1MS) and 7,7'-(((1E,1'E)-(((1E,1'E)-((9H-fluorene-2,7-diyl)bis(azanylylidene))bis(methanylylidene))bis(2,5-bis(octyloxy)-4,1phenylene))bis- (methanylylidene))bis(azanylylidene))bis(9H-fluoren-2-amine) (OIC2MS) were prepared by means of conventional and mechanochemical synthesis and characterized by FT-IR, 1H- and 13C-NMR techniques. The optical properties of the compounds were studied in solution by using UV-visible spectroscopy, and the optical effects were analyzed as a function of solvent. The results show that OIC2MS exhibits interesting photochromic properties. Furthermore, the structural and electronic properties of the compounds were analyzed by TD-DFT. It was found that the mechanosynthesis is an efficient method for the synthesis of both tetraimines.