Ligand-to-Metal Charge Transfer Excited States in Organometallic Compounds

Abstract

Organometallic compounds are an important class of materials in many areas of science and technology. In this Chapter, basic classification of electronically-excited states found in metal-based compounds is provided. The Chapter is devoted to the properties of ligand-to-metal charge transfer (LMCT) excited states as an extremely rare, much less studied type of electronically-excited states. In this Chapter, the knowledge on LMCT excited states, based on organometallic complexes, is surveyed and fundamental properties are discussed and generalized. Principal emphasis is given to investigations on solvatochromism, relation between LMCT transition energies and differences in oxidation and reduction potentials, relation between emission quantum efficiency and lifetime, electron-exchange (Dexter) resonant energy transfer, and photolysis of organometallic compounds in their LMCT excited states. Representative LMCT excited state cases, mainly referred to the group III – V organometallic complexes, are discussed aiding rationalization of the observed unique photophysics and photochemistry. There is great scope for novel chemical, photophysical, and photochemical studies of organometallic species, having long-lived emissive LMCT excited states, and their organized systems.