What determines the comproportionation constant in molecule-bridged mixed-valence complexes? Evidence for the crucial role of the ligand LUMO in four ruthenium(II)ruthenium(III) dimers

Ernst, Sylvia; Kasack, Volker; Kaim, Wolfgang

doi:10.1021/ic00280a010

Cited by 159 publications

(90 citation statements)

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“…UV/VIS (C H 3 CN): Amax = 243, 260, 531 nm. -!H NM R (CDCI3): ö = 7.55 (t, J = 4.9 Hz, 2H , H 5'), 9.13 (d,J = 4.9 Hz,4H ,H 4' 6'). -13C NM R (CDCI3): (3 = 122.7 (C5'), 158.5 (C4'-6'), 159.4 (C2'), 163.7 (C3'6).…”

Section: Methodsmentioning

confidence: 99%

The New Tetrafunctional π Acceptor Ligand 3,6-Bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz): Diruthenium Complexes of bmtz and of its 1,4-Dihydro Form

Kaim

Fees

1995

Zeitschrift Für Naturforschung B

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Synthesis, physical properties and the coordination with two [Ru(bpy)2]2+ complex frag ments are described for 3,6-bis(2'-pyrimidyl)-l,2,4,5-tetrazine (bmtz), the first compact ligand which offers four equivalent a-diimine chelate sites. Spectroelectrochemistry of intensely blue {(a-bmtz)[Ru(bpy)2]2}"+, n = 4, reveals a very facile reduction (n -3) at -0 .4 0 V vs. FeCp2+/o and a metal oxidation (n = 5) at +1.18 V to a diruthenium (II/III) mixed-valent form which exhibits an intervalence transfer absorption at 1490 nm. The corresponding complex {(M-H2bm tz)[Ru(bpy)2]2}4+ with the 1,4-dihydro form H 2bmtz of the tetrafunctional ligand is oxidized in two steps at 0.58 and 1.07 V vs. FeCp2+/°.

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Section: Methodsmentioning

confidence: 99%

The New Tetrafunctional π Acceptor Ligand 3,6-Bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz): Diruthenium Complexes of bmtz and of its 1,4-Dihydro Form

Kaim

Fees

1995

Zeitschrift Für Naturforschung B

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“…[62] Even complexes with two equivalent and approximately octahedrally coordinate metal centers can thus exist as meso W. Kaim and G. K. Lahiri Reviews (DL) and rac (LL/DD) stereoisomers in a situation as depicted in Scheme 2. [61,63,64] The corresponding mixedvalent states in general showed little difference in their electrochemical and spectroscopic features, [61] suggesting that the coordination framework is largely unaffected and that the valence-exchange mechanism is essentially unperturbed by this kind of isomerism. Similar results were reported for complexes with tris-bidentate ligands, such as HAT (e.g.…”

Section: Beyond "Spacers": Structurally Sophisticated Bridging Ligandsmentioning

confidence: 99%

Unconventional Mixed‐Valent Complexes of Ruthenium and Osmium

2007

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Recent developments have helped to extend the repertoire of mixed-valent ruthenium and osmium complexes beyond conventional systems. This extension has been achieved by using sophisticated ligands and by creating more variegated coordination patterns. The strategies employed include the use of multidentate ligands (which give rise to multinuclear and chelate complexes) and the use several redox active components (non-innocent ligands and oxidation-state ambivalence). The results offer enhanced chemical insight into metal-ligand electron-transfer situations and suggest that mixed-valent materials may eventually be exploited in molecular electronics and molecular computing.

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“…Synthesis and X-ray structure of 5 2,5-Diarylthiazolol [5,4-d]thiazoles are readily prepared from rubeanic acid and aromatic aldehydes. 8 In this way the ligand (5) was prepared from 2-pyridinecarboxaldehyde in 19% yield after recrystallisation, and characterised by mp, mass spectrometry and 1 H NMR.…”

Section: Resultsmentioning

confidence: 99%

“…4 The less symmetrical ligand 2,2'-azobis(pyridine) (2) leads to complexes with shorter metal-metal separations and stronger interactions. 5 In complexes of 2 the metals are laterally displaced relative to the plane of the ligand. As part of a programme involving the study of ligands containing less commonly studied heterocyclic ring systems, 6 we recently described the preparations and complexes of two new bridging ligands, (3) and (4), incorporating 1,2,5-oxadiazole and 1,2,5-thiadiazole bridging subunits.…”

Section: Introductionmentioning

confidence: 99%

“…7 In search of an explanation for the origin of this amplified communication between the metals, we have embarked on a project to synthesise related bridging ligands that contain mixed heteroatoms in the bridging subunit. We now report a study of the complexes of the title ligand (5), which has two laterally-displaced chelating binding domains separated by a thiazolothiazole bridge.…”

Section: Introductionmentioning

confidence: 99%

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Diastereoisomeric dinuclear ruthenium complexes of 2,5-di(2-pyridyl)thiazolo[5,4-d]thiazole

2004

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The first metal complexes of 2,5-di(2-pyridyl)thiazolol [5,4-d]thiazole (5) are described. X-Ray crystal structures are reported for the free ligand 5, a dinuclear copper complex 6 and the two diastereoisomers, 7meso and 7rac, of the dinuclear bis(2,2'-bipyridine)ruthenium complex. The two diastereoisomers of 7 and the 4,4'-dimethyl-2,2'-bipyridine analogue 8 are readily separated by cation exchange chromatography.1 H NMR and visible absorption spectra and electrochemical data for the four dinuclear ruthenium complexes reveal that these have relatively small HOMO-LUMO energy gaps and exhibit relatively weak metal-metal interactions.

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What determines the comproportionation constant in molecule-bridged mixed-valence complexes? Evidence for the crucial role of the ligand LUMO in four ruthenium(II)ruthenium(III) dimers

Cited by 159 publications

References 0 publications

The New Tetrafunctional π Acceptor Ligand 3,6-Bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz): Diruthenium Complexes of bmtz and of its 1,4-Dihydro Form

The New Tetrafunctional π Acceptor Ligand 3,6-Bis(2′-pyrimidyl)-1,2,4,5-tetrazine (bmtz): Diruthenium Complexes of bmtz and of its 1,4-Dihydro Form

Unconventional Mixed‐Valent Complexes of Ruthenium and Osmium

Diastereoisomeric dinuclear ruthenium complexes of 2,5-di(2-pyridyl)thiazolo[5,4-d]thiazole

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