The detection of toxic metal ions, such as Pb2+, has become important because they cause several health issues. This study describes the photophysical properties displayed by a few symmetrical diazine compounds and the influence of solvent polarity on their emission spectra. It is noted that λem increases with an increase in the polarity of the solvent. The study of the complexation of diazine compounds with metal ions, such as Cu2+, Ni2+, Co2+ and Pb2+, shows that the coordination of the metal ions to the diazine molecule induces a blue shift in the UV-visible absorption spectrum. Among the studied compounds, compound 1 exhibited the maximum emission (λem) in hexane at 309 nm, with a maximum quantum yield (Φem) of 0.0576. The metal interaction study shows that the absorption intensity of compound 1 reached the maximum for Pb, indicating that the synthesized diazine could serve as a potential molecule to detect Pb2+ ions. The experimental results were further supported by computational studies, and the experimental data were in good agreement with the theoretical data. The TDDFT study shows that for all the compounds, the λabs corresponds to the HOMO−1 to LUMO+1 transition.
Madarasi et al. (Thu,) studied this question.