Ferrocene ‐appended donor–π–acceptor Schiff base: Structural, nonlinear optical, aggregation‐induced emission and density functional theory studies

New donor –π‐acceptor ferrocenyl Schiff bases were synthesized and their nonlinear optical properties investigated. Frontier molecular orbital (HOMO–LUMO) energies were calculated. Aggregation‐induced emission studies revealed that the Schiff bases show strong dark yellow fluorescence emissions. New ferrocenyl Schiff bases [Fc ─C(H)═N─C6H3(OH)(R)] (R  = H (1), NO2 (2)) have been synthesized and characterized using various techniques. Compound2 was further confirmed using single ‐crystal X‐ray diffraction analysis. Solvatochromism studies of2 showed redshift from nonpolar to polar solvents. In addition, results of fluorescence studies indicated excellent aggregation ‐induced emission properties. The quasi‐reversible redox wave in electrochemical studies of the Schiff bases evidenced the electron transfer ability of ferrocene to the Schiff base (─C═N─) conjugation group. The second‐order nonlinear optical (NLO) properties of1 and2 were investigated using the Kurtz –Perry powder technique and2 showed an effect 1.46 times greater than that of urea reference. Although2 crystallized in the P21/c centrosymmetric space group, NLO property was observed, due to non ‐covalent interactions (C─H⋅⋅⋅π). The band gaps were calculated using the diffuse reflectance spectroscopic method and2 exhibited a low band gap of 2.9  eV which is due to the more electron‐withdrawing nature of the nitro group. Quantum chemical calculations were performed on ...

Source: Applied Organometallic Chemistry - October 23, 2018 Category: Chemistry Authors: Ezhumalai David, Krishnan Thirumoorthy, Nallasamy Palanisami Tags: FULL PAPER Source Type: research