Time-Resolved Electron Paramagnetic Resonance and Phosphorescence Studies of the Lowest Excited Triplet States of Rh(III) Corrole Complexes

Abstract

The lowest excited triplet (T(1)) ππ* states of gallium (Ga) and various rhodium (Rh) 5,10,15-trispentafluorophenyl corroles (Cors) were studied in the liquid crystal (LC) E-7 and in rigid glasses by time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy. The triplet sublevel energies were experimentally determined by the alignment of the molecules in the LC and by magnetophotoselection in the glass. The sublevel scheme of GaCor was determined by calculating the zero field splitting (ZFS) parameters. Axial ligand effects and quantum chemical calculations were used for the sublevel assignment of RhCors. The anisotropic EPR parameters were used to determine the important higher excited states and the magnitudes of their spin-orbit coupling (SOC) contributions were evaluated. On the basis of these results and analyses, the EPR parameters and triplet lifetime were discussed for each RhCor complex.

Spin–Orbit Charge‐Transfer Intersystem Crossing (ISC) in Compact Electron Donor–Acceptor Dyads: ISC Mechanism and Application as Novel and Potent Photodynamic Therapy Reagents

“…TREPR is a powerful tool to study the triplet excited states, and formation of radical pairs in organic compounds . Zero‐field splitting (ZFS) parameters D and E determined by TREPR give crucial information on the confinement of the triplet state wave function over the molecule and the rhombicity of the molecule at the triplet excited state.…”

“…Time-resolved electron paramagnetic resonance (TREPR) spectroscopy:I SC mechanism, triplet state wave function confinement and geometry-dependency of the spin-selectivity of the ISC of the dyads TREPR is ap owerful tool to study the triplet excited states, [68][69][70][71][72][73][74] and formation of radicalp airs in organic compounds. [75] Zerofield splitting (ZFS) parameters D and E determined by TREPR give crucial information on the confinement of the triplet state wave function overt he molecule and the rhombicity of the molecule at the triplet excited state.…”

Phosphorus corrole complexes: from property tuning to applications in photocatalysis and triplet–triplet annihilation upconversion

“…These different dihedral angles may safely be attributed to the iodine substitution in 1PF 2 -I 4 , which exerts some steric hindrance on the rotation of the aryl rings. The confinement of the triplet state wavefunction of the triplet state of corroles was previously studied by time-resolved electron paramagnetic resonance (TREPR), but the confinement of the triplet state was not discussed in detail 61…”

A Spectroscopic and Theoretical Investigation of a Free‐Base meso‐Trithienylcorrole

“…meso-Triaryl-substituted corroles were firstly described by Gross and co-workers in 1999 (11,12). Their syntheses were improved since (10,(13)(14)(15)(16), and numerous investigations illuminated the unique structural and electronic aspects of triarylcorroles (and their metal complexes) (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). The smaller trianionic corrolato ligand has a greater ability to stabilize higher central metal oxidation states than the larger dianionic porphyrinato ligand (35)(36)(37).…”