Synthesis, photophysical, electrochemical and computational studies of novel 2-aminoimidazolones with D-π-A framework

Two novel 2-aminoimidazolone derivatives based on donor-linker-acceptor (D-π-A) architecture (imidazoLUMS1 and imidazoLUMS2) have been synthesized and characterized by standard spectroscopic techniques. The donor building block in these compounds comprises of 4-benzylidene-2-(piperidin-1-yl)-1H-imidazol-5(4H)-one and 4-(thiophen-2-ylmethylene)-2-((3,4,5-trimethoxyphenyl)amino)-1H-imidazol-5(4H)-one respectively, while cyanoacetic acid was used as the electron acceptor linked to donor through a π-conjugated spacer. Synthetic methodology involved our multicomponent reaction following by Suzuki coupling and, Knoevenagel condensation reactions. ImidazoLUMS1 (λmax = 436 nm) and imidazoLUMS2 (λmax of 482 nm) showed a bathochromic shift of 58 nm and 104 nm with respect to their parent molecule 1 (λmax = 378 nm). The observed stoke shifts (Δλ = 134 nm and Δλ = 112 nm) and band gap values 2.40 eV and 2.26 eV support thermodynamic feasibility for intramolecular charge transfer character from donor to acceptor moiety. DFT studies, performed on GAUSSIAN 09, for the charge properties show their suitability for optoelectronic devices and an excellent correlation between experimental and computational data.