Probing the Metal-to-Ligand Charge Transfer First Excited State in (η6-Naphthalene)Cr(CO)3and (η6-Phenanthrene)Cr(CO)3by Resonance Raman Spectroscopy and Density Functional Theory Calculations

2011 ◽  
Vol 115 (42) ◽  
pp. 11641-11651 ◽  
Author(s):  
Gennaro Picardi ◽  
Tia E. Keyes ◽  
Robert J. Forster ◽  
Conor Long
Keyword(s):  
Density Functional Theory ◽  
Raman Spectroscopy ◽  
Excited State ◽  
Charge Transfer ◽  
Density Functional ◽  
Resonance Raman Spectroscopy ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Ligand Charge Transfer ◽  
First Excited State

A density functional theory and spectroscopic study of intramolecular quenching of metal-to-ligand charge-transfer excited states in some mono-bipyridine ruthenium(II) complexes

2014 ◽  
Vol 92 (10) ◽  
pp. 996-1009 ◽  
Author(s):  
Shivnath Mazumder ◽  
Ryan A. Thomas ◽  
Richard L. Lord ◽  
H. Bernhard Schlegel ◽  
John F. Endicott
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Lower Energy ◽  
Density Functional ◽  
Dimethyl Sulfide ◽  
Intramolecular Electron Transfer ◽  
Functional Theory ◽  
Ligand Charge Transfer

The complexes [Ru(NCCH3)4bpy]2+ and [Ru([14]aneS4)bpy]2+ ([14]aneS4 = 1,4,8,11-tetrathiacyclotetradecane, bpy = 2,2′-bipyridine) have similar absorption and emission spectra but the 77 K metal-to-ligand charge-transfer (MLCT) excited state emission lifetime of the latter is less than 0.3% that of the former. Density functional theory modeling of the lowest energy triplet excited states indicates that triplet metal centered (3MC) excited states are about 3500 cm−1 lower in energy than their 3MLCT excited states in both complexes. The differences in excited state lifetimes arise from a much larger coordination sphere distortion for [Ru(NCCH3)4bpy]2+ and the associated larger reorganizational barrier for intramolecular electron transfer. The smaller ruthenium ligand distortions of the [Ru([14]aneS4)bpy]2+ complex are apparently a consequence of stereochemical constraints imposed by the macrocyclic [14]aneS4 ligand, and the 3MC excited state calculated for the unconstrained [Ru(S(CH3)2)4bpy]2+ complex (S(CH3)2 = dimethyl sulfide) is distorted in a manner similar to that of [Ru(NCCH3)4bpy]2+. Despite the lower energy calculated for its 3MC than 3MLCT excited state, [Ru(NCCH3)4bpy]2+ emits strongly in 77 K glasses with an emission quantum yield of 0.47. The emission is biphasic with about a 1 μs lifetime for its dominant (86%) emission component. The 405 nm excitation used in these studies results in a significant amount of photodecomposition in the 77 K glasses. This is a temperature-dependent biphotonic process that most likely involves the bipyridine-radical anionic moiety of the 3MLCT excited state. A smaller than expected value found for the radiative rate constant is consistent with a lower energy 3MC than 3MLCT state.

Solvent effect on electron and proton transfer in the excited state of a hydrogen bonded phenol–imidazole complex

RSC Advances ◽  
2014 ◽  
Vol 4 (73) ◽  
pp. 38551-38557 ◽  
Author(s):  
Baotao Kang ◽  
Hu Shi ◽  
Shihai Yan ◽  
Jin Yong Lee
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Photosystem Ii ◽  
Ground State ◽  
Active Site ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Model System ◽  
Functional Theory ◽  
First Excited State

Density functional theory calculations have been carried out for the ground state (S0) and the first excited state (S1) of the H-bonded phenol and imidazole complex as a model system for the active site of photosystem II.

Investigation of Photo-Induced C-H Bond Activating by CpRh(CO)2 Complex Using Density Functional Theory

2011 ◽  
Vol 279 ◽  
pp. 170-173
Author(s):  
Qing Liong Liu ◽  
Shu Wei Wang ◽  
Li Lv ◽  
Xiao Jing Wang
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Charge Transfer ◽  
Transfer Process ◽  
Ground State ◽  
Density Functional ◽  
Light Irradiation ◽  
Functional Theory ◽  
Structural Distortions ◽  
First Excited State

The charge transfer and structural distortions that occurred in the complex CpRh(CO)2 upon excitation with an light irradiation were studied by density functional theory (DFT). The calculations showed that the electrons transferred from Cp to CO ligands with the transition of CpRh(CO)2 from ground state to the first excited state. Accompanying with this transfer process, CpM(CO)2 became distorted and the linear bond of M-CO became bent upon excitation. The second excitation is the strongest excitation which is identified to be metal to ligand CO charge transfer (MLCT) excitations. We also found the lowest excited state has little effect for the M-CO bond photoactivation while the photodissociation of CO from CpM(CO)2 can be achieved in the second excited state.

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