ODMR of triplet states of cofacial dimeric zinc porphyrins

Abstract

The triplet-state zero-field splitting parameters and the triplet sublevel decay rates for several monomeric zinc porphyrins and cofacial bis-zinc porphyrin dimers are reported. In the dimers, weak π-electron interactions between the porphyrin subunits are found to exist. Therefore the commonly used exciton model can be applied to obtain structural information about the excited triplet state of the dimers. In the β-linked dimers 1 and 2, the two porphyrin subunits are rotated with respect to one another about the common out-of-plane axis. These results suggest that these compounds were prepared and studied as the anti-, rather than syn-diastereoisomers. A meso-linked porphyrin dimer 3 was also studied.