Effects of weak metal-metal interactions in ligand-bridged complexes of ruthenium.  Dimeric complexes containing ruthenium ions in different coordination environments

Callahan, Robert W.; Brown, Gilbert M.; Meyer, Thomas J.

doi:10.1021/ic50149a001

Cited by 124 publications

(37 citation statements)

References 12 publications

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“…[27] The redshift could be due to interaction of 3p electrons of Cl À with dp electrons of the Ru II center, which elevates the energy level of the dp orbital and results in smaller energy gaps between the dp orbital and the p* orbitals of diimine ligands.…”

Section: Resultsmentioning

confidence: 99%

Ruthenium(II) Pyridylamine Complexes with Diimine Ligands Showing Reversible Photochemical and Thermal Structural Change

Kojima

Morimoto

Sakamoto

et al. 2008

Chemistry A European J

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Ruthenium(II)-TPA-diimine complexes, [Ru(TPA)(diimine)]2+ (TPA=tris(2-pyridylmethyl)amine; diimine=2,2'-bipyridine (bpy), 2,2'-bipyrimidine (bpm), 1,10-phenanthroline (phen)) were synthesized and characterized by spectroscopic and crystallographic methods. Their crystal structures demonstrate severe steric hindrance between the TPA and diimine ligands. They exhibit drastic structural changes on heating and photoirradiation at their MLCT bands, which involve partial dissociation of the tetradentate TPA ligand to exhibit a facially tridentate mode accompanied by structural change and solvent coordination to give [Ru(TPA)(diimine)(solvent)]2+ (solvent=acetonitrile, pyridine). The incoming solvent molecules are required to have pi-acceptor character, since sigma-donating solvent molecules do not coordinate. The thermal process is irreversible dissociation to give the solvent-bound complexes, which takes place by an interchange associative mechanism with large negative activation entropies. The photochemical process is a reversible reaction reaching a photostationary state, probably by a dissociative mechanism involving a five-coordinate intermediate to afford the same product as obtained in the thermal reaction. Quantum yields of the forward reactions to give dissociated products were lower than those of the backward reactions to recover the starting complexes. In the photochemical process, the conversions of the forward and backward reactions depend on the absorption coefficients of the starting materials and those of the products at certain wavelength, as well as the quantum yields of those reactions. The reversibility of the motions can be regulated by heating and by photoirradiation at certain wavelength for the recovery process. In the bpm system, we could achieve about 90 % recovery in thermal/photochemical structural interconversion.

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Section: Resultsmentioning

confidence: 99%

Ruthenium(II) Pyridylamine Complexes with Diimine Ligands Showing Reversible Photochemical and Thermal Structural Change

Kojima

Morimoto

Sakamoto

et al. 2008

Chemistry A European J

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“…2 presents its cyclic voltammogram. For the polynuclear species, the main features observed in the spectra may be easily assigned by comparing to the reported data for the model compounds [Ru(bpy) 2 (BPE)Cl]PF 6 and [Ru 3 O(CH 3 COO) 6 -(py) 2 (BPE)]PF 6 [41,54,55]. The intense bands in the ultraviolet region can be assigned to the pyridinic ligands p ?…”

Section: Esi-ms and Esi-ms/ms Structural Characterizationmentioning

confidence: 89%

Synthesis and characterization of the [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl](PF6)2 dimer

Nikolaou

Tomazela

Eberlin

et al. 2008

Transition Met Chem

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The polymetallic [Ru 3 O(CH 3 COO) 6 (py) 2 (BPE)-Ru(bpy) 2 Cl](PF 6 ) 2 complex (bpy = 2,2 0 -bipyridine, BPE = trans-1,2-bis(4-pyridil)ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru 3 O] moiety with a [Ru(bpy) 2 (BPE)Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS) spectrometry. The [Ru 3 O(CH 3 COO) 6 (py) 2 (BPE)Ru(bpy) 2 Cl] 2? doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy) 2 (BPE)] charge-transfer bands and to the [Ru 3 O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at -1.07 V, 0.13 V, 1.17 V, 2.91 V and -1.29 V (vs SHE) assigned to the [Ru 3 O] -1/0/?1/?2/?3 and to the bpy 0/-1 redox processes; also a wave is observed at 0.96 V, assigned to the Ru ?2/?3 pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling through the p-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation.

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“…The bridging ligand in multinuclear tethered complexes affects the properties of the assemblies, such as photoinduced energy transfer [145][146][147][148][149], and intervalence transition [150,151]. There are many examples of multifunctional CO 2 reduction photocatalysts with visible light absorbing antenna (e.g., [Ru(dmb) 3 ] 2+ derivatives) and CO 2 catalytic reduction centers (e.g., [Re(dmb)(CO) 3 Cl], where the catalytic activity strongly depends on the efficiency of electron transfer from reduced photosensitizers to catalytic centers [74,75,110,152,153].…”

Section: Structural Parameters For Supramolecular Catalyst Designmentioning

confidence: 99%

Conversion of CO2 via Visible Light Promoted Homogeneous Redox Catalysis

2012

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Abstract:This review gives an overview on the principles of light-promoted homogeneous redox catalysis in terms of applications in CO 2 conversion. Various chromophores and the advantages of different structures and metal centers as well as optimization strategies are discussed. All aspects of the reduction catalyst site are restricted to CO 2 conversion. An important focus of this review is the question of a replacement of the sacrificial donor which is found in most of the current publications. Furthermore, electronic parameters of supramolecular systems are reviewed with reference to the requisite of chromophores, oxidation and reduction sites.

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Effects of weak metal-metal interactions in ligand-bridged complexes of ruthenium. Dimeric complexes containing ruthenium ions in different coordination environments

Cited by 124 publications

References 12 publications

Ruthenium(II) Pyridylamine Complexes with Diimine Ligands Showing Reversible Photochemical and Thermal Structural Change

Ruthenium(II) Pyridylamine Complexes with Diimine Ligands Showing Reversible Photochemical and Thermal Structural Change

Synthesis and characterization of the [Ru3O(CH3COO)6(py)2(BPE)Ru(bpy)2Cl](PF6)2 dimer

Conversion of CO2 via Visible Light Promoted Homogeneous Redox Catalysis

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