Comments on Luminescence from Lowest MLCT Excited state of Mixed Amine Carbonyl Complexes of 6B Metal Group

Abstract

Abstract Dear Sir: During the last fifteen years several works related to the photo-chemistry and photophysics of M(CO)6-n(L)n. where the lowest excited state is generated by a metal ligand charge transfer (MLCT) process have been published in several journals (1–9). A single molecular description of the emission properties in terms of a luminescent triplet MLCT excited state is frequently invocated (1–9). However, two aspects not considered in all these published works have called our attention. First, radiative lifetimes determined from the singlet MLCT absorption spectra respect to those obtained from emission parameters as the experimental lifetimes and emission quantum yields are different in several orders of magnitude. Second, the heavy atom effect on going from the Mo to the W complexes is absent on luminescent properties of these assumed emitting triplet excited states.