Structural characterization, absorption and photoluminescence study of symmetrical azomethines with long aliphatic chains

In this study, we investigated structural and optical properties of three symmetrical azomethines bis(4-(4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 11-heptadecafluoroundecyloxy)benzylidene)benzene-1,4-diamine (SAz1), bis(4-(4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 11-heptadecafluoroundecyloxy)benzylidene)biphenyl-4,4′-diamine (SAz2) and 4,4′-methylenebis(N-(4-(octadecyloxy)benzylidene)benzenamine (SAz3). Electronic properties, such as orbital energies and resulting energy gap of the three symmetrical azomethines were calculated theoretically by density functional theory (DFT). The photoluminescence (PL) and absorption UV–vis properties of the azomethines were investigated in chloroform solution. The effect of excitation wavelength and concentration on the PL properties was detected as well. Azomethines emitted violet, blue or green light. The highest PL intensity was found for SAz1.