Synthesis and computational evaluation of imidazole-based functional materials for applications in sensing and detection: modulating electronic effects for enhanced performance

Herein, the synthesis of novel organic molecules 2,6-bis-(4,5-diphenyl-1-imidazole-2-yl)pyridine (3A), 2,6-bis-(7<i>H</i>-acenaphtho[1,2-<i>d</i>]imidazole-8-yl)pyridine (3B) and 2,6-bis-(1<i>H</i>-phenanthro[9,10-<i>d</i>]imidazole-2-yl)pyridine (3C) was reported. They were synthesized by the Debus-Radziszewski imidazole synthetic method and characterized by FTIR, UV-vis, ¹H NMR, ¹³C NMR and mass spectrometry. A density functional theory (DFT) approach was used to compute optical analysis, as well as the study of vibrational, frontier molecular orbitals (FMOs) and global indices of reactivity. The electronic transition was explored through the TD-DFT/B3LYP method, which employs time-dependent density functional theory calculations. The recently synthesized compounds were assessed for their fluorescence characteristics, and encouraging findings indicated that the emission efficiency was enhanced through the modulation of conjugation within a molecule. A highly sensitive and selective fluorescent chemosensor exhibited an "on-off" fluorescence response to Fe³⁺ with a 1 : 1 binding ratio in ethanol.