Metal–metal interactions in dinuclear ruthenium complexes containing bridging 4,5-di(2-pyridyl)imidazolates and related ligands

Slater, Jonathan W.; D’Alessandro, Deanna M.; Keene, F. Richard; Steel, Peter J.

doi:10.1039/b514976m

Cited by 29 publications

(22 citation statements)

References 57 publications

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“…The bridging ligands 2,3-bis(2-pyridyl)quinoxaline (dpb), 19 3,4-di(2-pyridyl)-1,2,5-oxadiazole (dpo), 10 and 4,5-di(2-pyridyl)imidazole (dpiH) 11 were prepared by literature methods [the latter two were a gift from Professor Peter Steel (University of Canterbury, Christchurch, New Zealand)]. The ruthenium complexes [{Ru(bpy) 2 } 2 (µ-dpb)](PF 6 ) 4 {dpb ) 2,3-bis(2-pyridyl)quinoxaline}, 20 [{Ru(bpy) 2 } 2 (µ-dpo)](PF 6 ) 4 , 10 and [{Ru-(bpy) 2 } 2 (µ-dpi -)](PF 6 ) 3 11 were synthesized and chromatographically separated into their diastereoisomeric forms, as reported previously.…”

Section: Methodsmentioning

confidence: 99%

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

Fellows

Keene

2007

J. Phys. Chem. B

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Spectroelectrochemical studies of the intervalence charge transfer (IVCT) characteristics of both diastereoisomeric forms of the dinuclear complex [{Ru(bpy)2}2(mu-dpi-)]n+ [bpy=2,2'-bipyridine; dpi-=4,5-di(2-pyridyl)imidazolate] showed that the degree of inter-metal electronic coupling (or valence delocalization) is dependent on stereochemical identity. Increasing the relative concentration of the strongly associating anion toluene-4-sulfonate in acetonitrile/[(n-C4H9)4N]{B(C6F5)4} solution differentially decreased the level of delocalization for the two diastereoisomers. In a comparative investigation of electrochemical and spectroelectrochemical techniques of the anion-induced electron localization in [{Ru(bpy)2}2(mu-dpo)]5+ [dpo=3,4-di(2-pyridyl)-1,2,5-oxadiazole], differences were observed between the two methods in the order and extent of effects induced by a number of inorganic anions (PF6-, BF4-, ClO4-). It was determined that the measure of coupling derived from electrochemical methods was less reliable than that obtained from spectral methods. Comparative electrochemical studies were undertaken on [{M(bpy)2}2(mu-BL)]n+ {M=Ru, Os; BL=dpo, dpi-), which revealed substantial differences in DeltaEox (the separation between the redox potentials for the MII-MII/MIII-MII and MII-MIII/MIII-MIII couples) for the two metal centers and therefore the comproportionation constant Kc, dependent on the neutral or anionic nature of the bridging ligand.

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Section: Methodsmentioning

confidence: 99%

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

Fellows

Keene

2007

J. Phys. Chem. B

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“…For the solid-state structures of 2,4,5-triphenylimidazoles, see: Kaftory et al (1998); Benisvy et al (2003); Martinez et al (2004); Seethalakshmi et al (2006); Thiruvalluvar et al (2007). For the synthesis of the title compound, see: Nakashima et al (1998); Slater et al (2006). For weak hydrogen-bond type contacts, see: Desiraju & Steiner (1999).…”

Section: Related Literaturementioning

confidence: 99%

2-Phenyl-4,5-di-2-pyridyl-1H-imidazole

2009

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In the title compound, C19H14N4, which was crystallized from dimethyl sulfoxide, the arene and heterocyclic rings of the lophine analogue framework differ only slightly from coplanarity (dihedral angles range from 8.8 to 20.2°), and intramolecular N—H⋯N and C—H⋯N interactions help to establish the conformation. The crystal packing features a number of weak C—H⋯N, N—H⋯N hydrogen-bond type contacts, and C—H⋯π interactions, leading to the formation of a herringbone structure.

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“…9 Also, five-membered ring heterocycles, such as imidazole, used as bridging ligands have been reported to mediate strong electronic coupling between coordinated metal ions. 10,11 We are also eager to study the effect of metal-metal electronic coupling in bimetallic Co(3,5-DBSQ) 2 complexes on valence tautomerism with the goal of producing "multistate" magnetic switching materials. Herein we describe the preparation and variable-temperature magnetic susceptibility properties of several Co(3,5-DBSQ) 2 complexes containing imidazole-or pyrazole-based ligands, including two bimetallic complexes.…”

Section: Introductionmentioning

confidence: 99%

Preparation, electrochemical behavior, and variable-temperature magnetic properties of Co(3,5-DBSQ)₂ complexes of imidazole- or pyrazole-substituted ligands

2015

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Herein we describe the preparation of four new Co(3,5-DBSQ) 2 containing known 2-(2-pyridyl)benzimidazole 1, 2,2=-bisbenzimidazole 2, or 2,2-(1H-pyrazole-3,5-diyl)dipyridine 3. We investigate the electronic and variable-temperature magnetic susceptibility properties of these complexes. Complexes containing 2 and 3 are bimetallic and variable-temperature magnetic susceptibility data suggest observation of a stable intermediate (high-spin and low-spin) state for the bimetallic complex with 3, which does undergo valence tautomerism. Complexes 4-6 containing imidazole-based ligands 1 and 2 feature high-spin ground states and no valence tautomerism is observed in these materials. This experimental finding is corroborated with density functional theory calculations, which support the existence of a stable high-spin ground state in these complexes. Résumé :Dans le présent article, nous décrivons la préparation de quatre nouveaux complexes de type Co(3,5-DBSQ) 2 dont les ligands connus sont le 2-(2-pyridyl)benzimidazole 1, le 2,2=-bis(benzimidazole) 2 ou la 2,2-(1H-pyrazole-3,5-diyl)dipyridine 3. Nous avons étudié ces complexes sous l'angle de leurs propriétés électroniques et de leurs propriétés de susceptibilité magnétique en fonction de la température. Les complexes comprenant les ligands 2 et 3 sont bimétalliques, et les données de susceptibilité magnétique en fonction de la température laissent supposer qu'on devrait observer un état intermédiaire stable (formes haut-spin et bas-spin) pour le complexe bimétallique avec le ligand 3, qui manifeste effectivement un tautomérisme de valence. Les complexes 4 à 6 comprenant les ligands à base d'imidazole 1 et 2 présentent des états fondamentaux de forme haut-spin, et aucun tautomérisme de valence n'est observé dans ces composés. Ce résultat expérimental est corroboré par des calculs de la théorie de la fonctionnelle de la densité, qui appuient l'existence d'un état fondamental stable de forme haut-spin dans ces complexes. [Traduit par la Rédaction]

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Metal–metal interactions in dinuclear ruthenium complexes containing bridging 4,5-di(2-pyridyl)imidazolates and related ligands

Cited by 29 publications

References 57 publications

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

2-Phenyl-4,5-di-2-pyridyl-1H-imidazole

Preparation, electrochemical behavior, and variable-temperature magnetic properties of Co(3,5-DBSQ)₂ complexes of imidazole- or pyrazole-substituted ligands

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Metal–metal interactions in dinuclear ruthenium complexes containing bridging 4,5-di(2-pyridyl)imidazolates and related ligands

Cited by 29 publications

References 57 publications

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

Influence of Anions on Intervalence Charge Transfer (IVCT) in Mixed-Valence Dinuclear Complexes

2-Phenyl-4,5-di-2-pyridyl-1H-imidazole

Preparation, electrochemical behavior, and variable-temperature magnetic properties of Co(3,5-DBSQ)2 complexes of imidazole- or pyrazole-substituted ligands

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Product

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Preparation, electrochemical behavior, and variable-temperature magnetic properties of Co(3,5-DBSQ)₂ complexes of imidazole- or pyrazole-substituted ligands