Synthesis of Novel Aqua ?4-NNNO/Cu(II) Complexes as Rapid and Selective Oxidative Catalysts for O-Catechol: Fluorescence, Spectral, Chromotropism and Thermal Analyses

A new tetradentate Schiff base (SB), (E)-4-fluoro-2-(1-((2-(piperazin-1-yl)ethyl)imino)ethyl)phenol, was synthesized from condensation of 2-(1-piperazinyl)ethylamine and 5-fluoro-2-hydroxyacetophenone. This ligand coordinated with three copper(II) salts (CuCl2, CuBr2 Cu(NO3)2?3H2O) separately, giving rise to neutral water-soluble Cu(II)/?4-NNNO complexes (1–3). The materials were fully characterized by standard spectroscopic, elemental, thermal, electronic, absorption, fluorescence analyses. chromotropism investigation the aqueous solutions revealed notable outcomes. turn off-on halochromism effect observed, both in acidic basic mediums. green-colored solution changed colorless (off) upon addition HCl, while initial green color reversibly restored (on) after NaOH. On other hand, bathochromic solvatochromism shifts noticed various solvents. Interestingly, complex 2 displayed a remarkable blue shift (?? = 90 nm) when compared its SB ligand. oxidation capability successfully demonstrated for conversion o-catechol o-benzoquinone presence H2O2, an environmentally friendly oxidant, under mild reaction conditions.