Aromatic chromophore-tethered Schiff base ligands and their iron(III)/chromium(III) Salen and Saloph capped complexes.

Aromatic chromophores; pyrene, phenanthrene, anthracene, naphtalene and benzene-tethered Schiff base ligands and their iron(III)/chromium(III) Salen and Saloph capped complexes have been synthesized. Compounds have been characterized by means of FT-IR Spectroscopy, (1)H-NMR Spectroscopy, Magnetic Susceptibility, Elementel Analsis, TG/DTA measurements. Their fluorescence and absorbance properties have been investigated by Luminescence Spectroscopy and UV-vis Spectroscopy. Generally, ligands show an intense excimer fluorescence emissions in acetonitrile-methanol medium while iron(III) and chromium(III) complexes exhibit low fluorescence's. Intensity compared to ligands iron and chromium centers act as an extra chromophore that quench the pyrene, phenanthrene, anthracene, naphtalene and benzene molecules' singlet state. The mechanism of quenching is attributed to a iron (or chromium)-to-pyrene (or phenanthrene, anthracene, naphtalene and benzene) electronic energy transfer process.