A combined experimental and theoretical investigation of imidazole-carbazole fluorophores

Two different tri and tetra substituted imidazole derivatives connected with carbazole moiety were synthesized by using Vilsmeier-Haack formylation followed by multicomponent cyclisation reaction. Results obtained from spectroscopic (1H NMR, 13C NMR, Mass) and single crystal X-ray diffraction analysis of synthesized compound revealed its chemical structure. UV-vis and photoluminescence studies in various solvents with different polarity demonstrated that these compounds were sensitive to the polarity of the microenvironment in the excited state. Results of TGA and AFM analysis demonstrated that the compounds exhibited good thermal and morphological stabilities over very harsh conditions. DFT calculations were performed to elucidate the structural and electrochemical properties of these compounds. The computed result revealed the ground state of the molecules was majorly stabilized by σ→σ⁎ interaction and the natural hybrid orbital compositions and occupancies predict that the bonding interactions between C and N centers possess pure σ bond with sp2 hybridization.