Fluorescence properties of halogenated mono-hydroxyl corroles: The heavy-atom effects

A series of mono-hydroxyl corrole bearing a fluorine (1), chlorine (2), bromine (3) and iodine (4) atom on its 10-phenyl group have been synthesized. Fluorescence spectroscopy shows that the halogen atom at meso-phenyl group of corroles exhibit significant heavy-atom effect on their photophysical properties. Fluorescence quantum yields and the lifetime of these corroles decrease with the increasing of the atomic weight of halogen atoms. The quenching of the fluorescence could be interpreted in terms of a heavy atom-induced increase in intersystem crossing from S₁ to T ₁. The intersystem crossing rate constant of these corroles were also determined by transient fluorescence spectra.