Title
Optical Activity of Spin-Forbidden Electronic Transitions in Metal Complexes from Time-Dependent Density Functional Theory with Spin-Orbit Coupling
Author
Herbert D. Ludowieg, Prof. Monika Srebro-Hooper, Dr. Jeanne Crassous, Prof. Jochen Autschbach
Year
2022
Journal
ChemistryOpen
Abstract
Circularly polarized luminescence (CPL) dissymmetry factors and phosphorescence lifetimes are calculated for the spin-forbidden triplet emission of metal-helicene complexes. Spin-forbidden singlet-triplet excitations and electronic circular dichroism are calculated for tris(ethylenediamine)cobalt(III). The results agree well with reported experimental data. Calculations are based on two-component relativistic time-dependent density functional response including the effects from spin-orbit coupling.The calculation of magnetic transition dipole moments and rotatory strengths was implemented at the zeroth-order regular approximation (ZORA) two-component relativistic time-dependent density functional theory (TDDFT) level. The circular dichroism of the spin-forbidden ligand-field transitions of tris(ethylenediamine)cobalt(III) computed in this way agrees very well with available measurements. Phosphorescence dissymmetry factors urn:x-wiley:21911363:media:open202200020:open202200020-math-0001 and the corresponding lifetimes are evaluated for three N-heterocyclic-carbene-based iridium complexes, two of which contain helicene moieties, and for two platinahelicenes. The agreement with experimental data is satisfactory. The calculations reproduce the signs and order of magnitude of urn:x-wiley:21911363:media:open202200020:open202200020-math-0002 , and the large variations of phosphorescence lifetimes among the systems. The electron spin contribution to the magnetic transition dipole moment is shown to be important in all of the computations.
Instrument
CPL-300
Keywords
CPL, phosphorescence, spin-orbit coupling