Spectroscopic and ODMR investigations of the lowest ππ* and ligand-ligand charge-transfer excited states of zinc(II) mixed-ligand complexes

1992 ◽  
Vol 104 (2) ◽  
pp. 241-249
Author(s):  
Kaoru Nozaki ◽  
Shigeru Ikeda ◽  
Seiichi Yamamoto ◽  
Takeshi Ikeyama ◽  
Tohru Azumi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Ligand Charge Transfer

Synthesis and Photochemical Properties of Re(I) Tricarbonyl Complexes Bound to Thione and Thiazole-2-ylidene Ligands

2020 ◽  
Author(s):  
Matthew Stout ◽  
Brian Skelton ◽  
Alexandre N. Sobolev ◽  
Paolo Raiteri ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Exchange ◽  
Ligand Substitution ◽  
Bidentate Ligand ◽  
The Other ◽  
Ligand Exchange Reaction ◽  
Multiple Products ◽  
Ligand Charge Transfer ◽  
Photochemical Properties

<p>Three Re(I) tricarbonyl complexes, with general formulation Re(N^L)(CO)<sub>3</sub>X (where N^L is a bidentate ligand containing a pyridine functionalized in the position 2 with a thione or a thiazol-2-ylidene group and X is either chloro or bromo) were synthesized and their reactivity explored in terms of solvent-dependent ligand substitution, both in the ground and excited states. When dissolved in acetonitrile, the complexes bound to the thione ligand underwent ligand exchange with the solvent resulting in the formation of Re(NCMe)<sub>2</sub>(CO)<sub>3</sub>X. The exchange was found to be reversible, and the starting complex was reformed upon removal of the solvent. On the other hand, the complexes appeared inert in dichloromethane or acetone. Conversely, the complex bound to the thiazole-2-ylidene ligand did not display any ligand exchange reaction in the dark, but underwent photoactivated ligand substitution when excited to its lowest metal-to-ligand charge transfer manifold. Photolysis of this complex in acetonitrile generated multiple products, including Re(I) tricarbonyl and dicarbonyl solvato-complexes as well as free thiazole-2-ylidene ligand.</p>

Molecular and electronic structure in the metal-to-ligand charge-transfer excited states of d6 transition-metal complexes in solution

1984 ◽  
Vol 106 (12) ◽  
pp. 3492-3500 ◽  
Author(s):  
Jonathan V. Caspar ◽  
T. David Westmoreland ◽  
George H. Allen ◽  
Paul G. Bradley ◽  
Thomas J. Meyer ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Transfer ◽  
Transition Metal ◽  
Metal Complexes ◽  
Excited States ◽  
Transition Metal Complexes ◽  
Ligand Charge Transfer ◽  
Molecular And Electronic Structure

Subpicosecond Dynamics of Metal-to-Ligand Charge-Transfer Excited States in Solvated [Ru(bpy)3]2+ Complexes

2011 ◽  
Vol 115 (31) ◽  
pp. 15617-15626 ◽  
Author(s):  
Diego A. Hoff ◽  
Robson Silva ◽  
Luis G. C. Rego
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ligand Charge Transfer

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.

Contrasts in the 77 K Emission Spectra, Structures, and Dynamics of Metal-to-Metal and Metal-to-Ligand Charge-Transfer Excited States†

2007 ◽  
Vol 111 (24) ◽  
pp. 6748-6760 ◽  
Author(s):  
Yuan-Jang Chen ◽  
John F. Endicott ◽  
Patrick G. McNamarra
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Emission Spectra ◽  
Ligand Charge Transfer
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