Photoinduced electron transfer process on emission spectrum of N,N′-bis(salicylidene)-1,2-phenylenediamine as a Mg2+ cation chemosensor: A first principle DFT and TDDFT study

Abstract

The electronic and optical properties of N,N′-bis(salicylidene)-1,2-phenylenediamine (SPDA) ligand were studied as a chemical sensor of Mg2+ cation in two solvents (water and DMSO) using the ab initio theory through Density Functional Theory (DFT) and Time Dependent Density Functional theory (TDDFT) methods. The results show that the SPDA ligand has a high ability for chemical sensing of Mg2+. The results has also represented that HOMO-LUMO energy gap decreases 0.941 eV after the complex formation between SPDA and Mg2+. In addition, obvious changes are found in the UV–Vis absorption spectrum, optical analyses SPDA ligand and [SPDA.Mg]2+ complex, which it has the capability of detecting Mg2+ via the adsorptive UV–Vis and colorimetric methods. Emission spectrum calculations and photoinduced electron transfer (PET) process in water solution shows different wavelength emission spectrum in amount of 4.6 nm. An analysis of NBO (natural bond orbital) data indicates tangible changes in the electron transfers data from the electron pairs of ligand to the conjugated system, both prior and subsequent to Mg2+addition.