Abstract

A fragmentation scheme combined with a series of theoretical approximations like TD-DFT, and multiconfigurational CASSCF/NEVPT2 methods, has been used to describe the photophysical phenomena associated with the antenna effect and lanthanide ion emission. The theoretical protocol was used in (Cp-2Ph)(3)Tb and (Cp-2Ph)TbCl2(THF)(3), where Cp-2Ph= diphenylcyclopentadienyl and THF = tetrahydrofuran, organometallic complexes recently reported by Roitershteinet al.(Inorg. Chem., 2018,57, 10199) The excited-state dynamic of the antenna ligand shows an important vibronic coupling associated with the radiative and non-radiative process with rate constants in the order normally reported for organic molecules. The methodology proposed herein allows a justification of the back-energy transfer observed experimentally in the (Cp-2Ph)(3)Tb complex and the efficient energy transfer mechanism in (Cp-2Ph)TbCl2(THF)(3), thus proving to be a robust tool in the determination of the sensitization pathways in organometallic lanthanide complexes.