Synthesis, photophysical studies, and application of novel 2,7-bis((1-butyl-1H-1,2,3-triazol-4-yl)methoxy)naphthalene as a highly selective, reversible fluorescence chemosensor for detection Fe3+ ions

Abstract

The new reversible turn-off fluorescence chemosensor 2,7-bis((1-butyl-1H-1,2,3-triazol-4-yl)methoxy)naphthalene for selective detection of Fe3+ ions has been designed and synthesized using a multicomponent approach. The absorption and emission characteristics of this new chemosensor were studied in different solvents of varying polarities. The ground and excited state dipole moments were determined experimentally by solvatochromic methods and theoretically using DFT/TD-DFT calculations. The effect of common metal ions on emission spectra was investigated. The results showed that it can be used as reversible turn-off fluorescence chemosensor to determine Fe3+ ions with high selectivity among a series of other common cations. The binding stoichiometry of chemosensor with Fe3+ ions and association constant was investigated using global fit analyses as proposed by Thordarson. The mechanism of fluorescence quenching was studied by using a Stern-Volmer plot. The linear range of the chemosensor for detection of Fe3+ ions was found to be 8.0×10−7M to 1.0×10−5M with limit of detection (LOD) of 8.7×10−7M and limit of quantification (LOQ) of 2.6×10−6M. The Frontier molecular orbitals (FMO) analysis and chemical reactivity indices of this new chemosensor were also studied using DFT/TD-DFT calculations. The non-linear optical properties were also investigated. The values of total polarizability and first-order hyperpolarizability for the chemosensor were found to be higher than the standard urea molecule. Thus it can also be used as a potential NLO material. The thermodynamic parameters were also investigated.