Ligand-centered to metal-centered activation of a Rh(iii) photosensitizer revealed by molecular dynamics simulations.

Excited state evolution of the rhodium(iii) complex [Rh(iii)(phen)(NH)] (phen = 1,10-phenanthroline) has been investigated theoretically to gain a better understanding of light-driven activation of high-energy metal centered states. molecular dynamics (AIMD) simulations show the significance of asymmetric motion on a multidimensional potential energy landscape around the metal center for activated crossover from triplet ligand centered (LC) to triplet metal centered (MC) states on picosecond timescales. Significant entropic differences arising from the structural distributions of the LC and MC states revealed by the simulations are found to favor the forward crossover process.

Competing dynamics of intramolecular deactivation and bimolecular charge transfer processes in luminescent Fe(iii) N-heterocyclic carbene complexes.

Steady state and ultrafast spectroscopy on [Fe(phtmeimb)]PF (phtmeimb = phenyl(tris(3-methylimidazol-2-ylidene))borate) was performed over a broad range of temperatures. The intramolecular deactivation dynamics of the luminescent doublet ligand-to-metal charge-transfer (LMCT) state was established based on Arrhenius analysis, indicating the direct deactivation of the LMCT state to the doublet ground state as a key limitation to the lifetime. In selected solvent environments photoinduced disproportionation generating short-lived Fe(iv) and Fe(ii) complex pairs that subsequently undergo bimolecular recombination was observed.