1H, 1, 2, 3- Triazole Tethered imidazole-Isatin conjugates: Synthesis, DFT and optical properties

Abstract

Novel functional materials, namely TPI-TAZ-ISA, NADPI-TAZ-ISA, ADPI-TAZ-ISA, and DMAPDPI-TAZ-ISA, were synthesized utilizing click chemical reactions and subjected to thorough characterization. The optical properties of these organic materials, TPI-TAZ-ISA, NADPI-TAZ-ISA, ADPI-TAZ-ISA, and DMAPDPI-TAZ-ISA, were investigated in various solvent environments. Notably, ADPI-TAZ-ISA exhibited a maximum absorption wavelength of 390 nm attributed to π – π* electronic transitions, primarily originating from the fluorophore group, while displaying a blue fluorescence at 465 nm. A comprehensive investigation combining experimental and theoretical approaches was conducted for these compounds, revealing a non-planar molecular structure and theoretical energy band gaps ranging from 4.10 to 4.73 eV. DFT studies demonstrated well-defined spatial separation of the HOMO and LUMO for all compounds in the ground state (S0). NTO studies further elucidated the spatial separation of the HONTO and LUNTO for DMAPDPI-TAZ-ISA at the excited state (S2), corroborated by CDD, hole and electron contributions, and the overlap of hole and electron densities. These findings hold promise for the development of novel luminescent materials. Moreover, on-going research is exploring the integration of ISA to enhance the functionality of these materials further.