The present investigation has a twofold aim. In the first place, the ground-state spectroscopic features of three IrIII polypyridyl complexes were studied by computational means, in order to elucidate the nature of their UV-visible spectra and electrochemical behaviour. Coincidentally, the limited but variegated set of molecules was employed to analyse how different exchange-correlation functionals model the properties of interest in the presence of transition metal atoms. These iridium complexes involve various terdentate ligands: a N[logical and]N[logical and]N bonded ttpy derivative (ttpy = 4[prime]-tolyl-2:2[prime],6[prime]:2[double-prime]-terpyridine), a C[logical and]N[logical and]C bonded dppy derivative (dppy = 2,6-diphenyl-pyridine), a C[logical and]N[logical and]N pbp derivative (pbp = 6-phenyl-2:2[prime]-bipyridine). The axially-symmetric-homoleptic or heteroleptic-arrangement gives the low-lying excited states of these molecules a unique directional nature. Analysis of the electronic transitions calculated by first-principle method based on time-dependent density functional theory (TDDFT) gives insight on their steady-state visible absorption bands. The comparison of generalised-gradient approximation (GGA) functionals (BLYP and G96LYP) with hybrid GGA functionals (B3LYP and PBE0) values the consequences of the nonlocal Hartree–Fock exchange embedded in the latter.
Iridium Complexes with Terdentate Ligands: Cyclometalated vs. Polypyridine Analogues; Hybrid vs. ``Pure'' DFT
RAVAGLIA, Marcella;SCANDOLA, Franco
2007
Abstract
The present investigation has a twofold aim. In the first place, the ground-state spectroscopic features of three IrIII polypyridyl complexes were studied by computational means, in order to elucidate the nature of their UV-visible spectra and electrochemical behaviour. Coincidentally, the limited but variegated set of molecules was employed to analyse how different exchange-correlation functionals model the properties of interest in the presence of transition metal atoms. These iridium complexes involve various terdentate ligands: a N[logical and]N[logical and]N bonded ttpy derivative (ttpy = 4[prime]-tolyl-2:2[prime],6[prime]:2[double-prime]-terpyridine), a C[logical and]N[logical and]C bonded dppy derivative (dppy = 2,6-diphenyl-pyridine), a C[logical and]N[logical and]N pbp derivative (pbp = 6-phenyl-2:2[prime]-bipyridine). The axially-symmetric-homoleptic or heteroleptic-arrangement gives the low-lying excited states of these molecules a unique directional nature. Analysis of the electronic transitions calculated by first-principle method based on time-dependent density functional theory (TDDFT) gives insight on their steady-state visible absorption bands. The comparison of generalised-gradient approximation (GGA) functionals (BLYP and G96LYP) with hybrid GGA functionals (B3LYP and PBE0) values the consequences of the nonlocal Hartree–Fock exchange embedded in the latter.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
