Hole-burning and luminescence line narrowing in [IrCl2(5,6-Me2-phen)2]+. A strongly perturbed 3LC state

Abstract

Absorption, luminescence, excitation, MCD, and MCPL spectra of [IrCl2(5,6-Me2-phen)2]+ are reported in frozen glasses. In this complex, MLCT states lie close to the triplet ligand-centered (3LC) emitting state. The latter state is identified in absorption for the first time. The assignment of the emitting state as 3LC is unambiguously confirmed by the characteristic S = 1, g, = 2 Zeeman splittings on resonantly narrowed luminescence spectra, performed in a glycerol host. The zero-field splitting (ZFS) is found to be large, with a maximum splitting \D\ + \E\ ≅ 3 cm-1. This anomalously high ZFS magnitude indicates a significant perturbation of the 3LC state, possibly by the close-lying charge-transfer states. Persistent spectral holes could be burned by the 488-nm Ar+ laser line showing a homogeneous line width of less than 140 MHz at 1.5 K for very shallow holes. Show more