Mechanism of associative photoinduced ligand substitution in tetracarbonyl(phenanthroline)tungsten under metal-to-ligand charge-transfer excitation: subnanosecond transient spectra and solvent and wavelength dependence evidence for rapid primary processes

1993 ◽  
Vol 32 (11) ◽  
pp. 2269-2275 ◽  
Author(s):  
Elspeth Lindsay ◽  
Antonin Vlcek ◽  
Cooper H. Langford
Keyword(s):  
Charge Transfer ◽  
Wavelength Dependence ◽  
Ligand Substitution ◽  
Ligand Charge Transfer ◽  
Transient Spectra ◽  
Charge Transfer Excitation

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>

scholarly journals 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>

Monomeric thorium chalcogenolates with bipyridine and terpyridine ligands

2018 ◽  
Vol 47 (41) ◽  
pp. 14652-14661 ◽  
Author(s):  
Marissa Ringgold ◽  
Wen Wu ◽  
Matthew Stuber ◽  
Anna Y. Kornienko ◽  
Thomas J. Emge ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Ligand Charge Transfer ◽  
Charge Transfer Excitation ◽  
Terpyridine Ligands ◽  
Coordinate Structures

Thorium chalcogenolates react with bipyridine or terpyridine to form a series of chelate stabilized Th(ER)4 compounds (E = S, Se; R = Ph, C6F5). 77Se NMR shows that the eight coordinate structures are maintained in solution. These compounds are thermochromic, with color originating from a visible ligand to ligand charge transfer excitation.

Photodisproportionation of (1,5-Cyclooctadiene) copper(I) Hexafluoroacetylacetonate Induced by Metal-to-Ligand Charge Transfer Excitation

2003 ◽  
Vol 58 (7) ◽  
pp. 704-707 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Quantum Yields ◽  
Long Wavelength ◽  
Ligand Charge Transfer ◽  
Elemental Copper ◽  
Charge Transfer Excitation ◽  
Reactive Excited State

The complex CuI(COD)(hfac) with COD = 1,5- cyclooctadiene and hfac = hexafluoroacetyl-acetonate shows two long-wavelength absorptions at λmax = 308 and 241 nm which are assigned to hfac intraligand (IL) and CuI →COD metal-to-ligand charge transfer (MLCT) transitions, respectively. The photolysis of CuI(COD)(hfac) in hexane leads to the release of the olefin and the subsequent disproportionation of CuI(hfac) to elemental copper and CuII(hfac)2 with the quantum yields Φ = 10−3 at λirr =313 nm and Φ = 3×10−3 at λirr = 254 nm. It is suggested that the reactive excited state is of the MLCT type.

The Transmission of Substituent Effects in Transition Metal Complexes

1971 ◽  
Vol 49 (1) ◽  
pp. 56-66 ◽  
Author(s):  
D. R. Eaton ◽  
K. L. Chua
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Charge Transfer ◽  
Magnetic Resonance ◽  
Transition Metal ◽  
Transition Metal Complexes ◽  
Opposite Effect ◽  
Substituent Effects ◽  
Ligand Substitution ◽  
Simple Interpretation ◽  
Ligand Charge Transfer

The effect of ligand substitution on bonding to other ligands has been investigated in a series of V(III) complexes. Nuclear magnetic resonance (n.m.r.) contact shifts have been utilized for this purpose. These shifts are interpreted as arising from metal to ligand charge transfer. The results obtained are contrary to those expected from simple considerations of the electron withdrawing or donating abilities of the substituents. Electron withdrawing substituents decrease the charge transfer to the substituted ligand and increase the charge transfer to the remaining ligands. Electron donating substituents have the opposite effect. A simple interpretation is proposed to account for these results. An electron withdrawing substituent on a ligand in the xy plane increases the occupancy of dxy which cannot interact with the π system of the ligand in the xy plane but which is available for π bonding with the remaining ligands. Effects of this type are to be anticipated whenever the filling of the t2g orbitals is not symmetrical.

Sign in / Sign up

Export Citation Format

Share Document