Photochromic and Electrochromic Study of Schiff Bases Containing Pyrazolone and Anthracene Unit

New Schiff bases 4-((anthracen-2-ylimino) methyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (1C), 4-(1-(anthracen-2-ylimino)ethyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (2C) and 4-((anthracen-2-ylimino)(phenyl)methyl)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one (3C) were synthesised and characterized by elemental analyses, LC-MS, FTIR and 1H NMR spectra. The photochromic property of the synthesised compound investigated under 365 nm UV-light irradiation, which can be observed with solution and solid-state absorption spectra. The kinetics study show that the photochromic reaction is of peusdo first order. The photoisomerization is due to photoinduced intramolecular hydrogen bond, which results in enol to keto transformation. The electrochromic properties in solution were checked using cyclic voltametric (CV) results in acetonitrile solvent. The CV result indicates that all three compounds show electrochromic behaviour in solution state. Further frontier molecular orbitals (FMOs) of all molecule in keto and enol form calculated using B3LYP/6-31G* which also relatable with experimental data.