Trans influence and substituent effects on the HOMO-LUMO energy gap and Stokes shift in Ru mono-diimine derivatives

Theoretical Explorations of Structural, Electronic, and Spectroscopic Properties of a Series of Ruthenium Schiff-Base Complexes

“…The values reveal that the energies of HOMO and LUMO are increased when an electrondonating substituent is present (CH 3 ) and vice versa when an electron-withdrawing group (Cl, CF 3 ) is added. This trend in the change in energy levels of HOMO and LUMO in transition metal complexes, with the addition of electron-withdrawing or donating groups, is well recorded in the literature [62][63][64][65]. Although the energies of HOMO and LUMO decrease for both [Ru(PPh 3 ) 2 (CO)(L-Cl)] and [Ru(PPh 3 ) 2 (CO)(L-CF 3 )], the extent of decrease in energy of LUMO in comparison to that of HOMO is far greater in case of the CF 3 substituted complex.…”

White light employing luminescent engineered large (mega) Stokes shift molecules: a review

“…In 2019, AlAbbad and his group recently scrutinized the trans influence and substituent effects on the HOMO–LUMO energy gap and Stokes shift component in ruthenium mono-diimine derivatives. 137 The push–pull effect in the context of the metal complex was sourced from the strong oxidant of the Ru metal. Electrons transfer from the t 2 g orbital of Ru to the low-lying π* molecular orbital of the 2,2′-bipyridyl ligand, invoking a singlet ground state (S 0 ) to singlet metal-to-ligand charge transfer ( 1 MLCT).…”

Synthesis, structure, photophysical and electrochemical properties of Ru(TFA)(CO)(PPh3)2(L) (L=2-phenylpyridine, 2-p-tolylpyridine) and Ru(CO)(PPhMe2)2(L)(L′) (L= TFA, H) (L′= bipyridine, L′= 4,4′-dimethylbipyridine) relationships between ancillary ligand structure and luminescent properties

“…However, the complexes were only moderately stable in solution [4]. Measurements of the excitation spectra and time dependent density functional theory calculations indicates the phosphine ligand has a significant contribution to the excited state in these complexes [5]. With these observations in mind we decided to synthesize the 2-phenylpyridine (ppy) analogs of the bpy complexes and replaced the bulky PPh 3 with the smaller and more electron-donating PPhMe 2 .…”