Structural consequences of electron-transfer reactions. 26. Evidence for time-dependent valence detrapping in a mixed-valent dimanganese fulvalenyl cation

Atwood, Christopher G.; Geiger, William E.; Rheingold, Arnold L.

doi:10.1021/ja00065a059

Cited by 69 publications

(38 citation statements)

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“…Figure compares the experimental spectra of Ru 2 BTD •+ and Ru 2 v BTD 2 •+ to the simulated spectra obtained with the parameters summarized in Table ; those of the other complexes are displayed in Figures S35–S37. This renders radical cations Ru 2 v BTD 2 •+ , Ru 2 e BTD 2 •+ , and Ru 2 v p-phen 2 •+ further examples of mixed-valent systems that are delocalized on the slower EPR time scale despite exhibiting only partial valence delocalization on the faster IR time scale. ,,,,, Of further note is the even closer proximity of the g values of the present radical cations to the free electron value g e , which is usually considered as an indicator for an enhanced ligand character of such radicals. − This is particularly evident for Ru 2 v BTD 2 •+ and, to a somewhat lesser extent, its ethynyl-bridged analog Ru 2 e BTD 2 •+ . Computed spin density distributions, which are also displayed in Figures S35–S37, are in line with this kind of reasoning (Table ).…”

Section: Resultsmentioning

confidence: 85%

“…Figure 4 valent systems that are delocalized on the slower EPR time scale despite exhibiting only partial valence delocalization on the faster IR time scale. 4,8,33,65,82,83 Of further note is the even closer proximity of the g values of the present radical cations to the free electron value g e , which is usually considered as an indicator for an enhanced ligand character of such radicals. 84−86 This is particularly evident for Ru 2 v BTD 2…”

Section: •+mentioning

confidence: 99%

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Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

2019

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We present four new divinylarylene-bridged diruthenium complexes of the type {Ru(CO)Cl(P i Pr3)2}2(μ-CHCH–Ar–CHCH) with naphthalene-1,4-diyl (Ru 2 NA), 2,1,3-benzothiadiazole (Ru 2 BTD), bis(benzothiadiazolyl)ethene (Ru 2 v BTD 2 ), or bis(benzothiadiazolyl)ethyne (Ru 2 e BTD 2 ) as the arylene units. The radical cations of the complexes with shorter arylene bridges are intrinsically valence-delocalized on the IR time scale. In contrast to phenylene-bridged [{Ru(CO)Cl(P i Pr3)2}2(μ-CHCH–C6H4-1,4-CHCH)]2+ (Ru 2 -p-phen 2+ ), the dioxidized forms of complexes Ru 2 BTD and Ru 2 NA are electron paramagnetic resonance (EPR) silent. Replacing the E-stilbenediyl linker of the complex {Ru(CO)Cl(P i Pr3)2}2(μ-CHCH–C6H4–CHCH–C6H4–CHCH) (Ru 2 v p-phen 2 ) by vBTD2 or eBTD2 enhances electronic coupling and charge delocalization of their one-electron-oxidized mixed-valent forms. While the latter radical cations are still charge-localized species on the IR time scale, they are fully delocalized on the slower EPR time scale. As a token of a quinoidally distorted bridge, Ru 2 e BTD 2 2+ features a characteristic IR stretch of a cumulenic CCCC increment. For compound Ru 2 v BTD 2 , rearrangement to a quinoidal structure is manifested through potential inversion (i.e., the half-wave potential of the second oxidation is lower than that of the 0/1+ redox couple) in the CH2Cl2/NBu4BArF electrolyte. The BTD complexes are intensely colored in their neutral states and exhibit strong NIR absorptions of their radical cations as well as of their dioxidized forms.

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Section: Resultsmentioning

confidence: 85%

Section: •+mentioning

confidence: 99%

Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

2019

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“…Photolytic decarbonylation of 2 and deprotonation using KO t Bu gave K + 3 − , the first bimetallic complex of type B . Its formation can be monitored by IR spectroscopy through the characteristic changes of the CO stretching frequencies (2015/1927 cm −1 for 2 versus 1919(1896)/1848(1816) cm −1 for 3 − ) 8…”

Section: Methodsmentioning

confidence: 99%

Bifunctional Cp∩N Complexes—Unusual Structural Features and Electronic Coupling in Highly Preorganized Bimetallic Systems

Röder

Meyer

Kaifer

2002

Angew. Chem. Int. Ed.

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Dedicated to Professor Lutz F. Tietze on the occasion of his 60th birthdayComplexes of cyclopentadienyl (Cp) ligands with functional amino or amido side chains are currently receiving enormous attention in organometallic chemistry. [1,2] While the donor substituent tethered to the Cp moiety usually serves a hemilabile chelate function in generic type A complexes, we recently put forward a novel approach in which a pyrazolate group in complexes of type B links two Cp units and acts both as an intramolecular N donor and as a bridging group spanning two metal ions . [3] Such a strategy, that is the formal coupling of two N-containing ligand compartments through a functionalized pyrazolate bridge to constitute a preorganized dinuclear scaffold, has successfully been employed for mimicking cooperative effects in biomimetic coordination compounds. [4] Accordingly, type B systems are now expected to give rise to novel organometallic chemistry in which two adjacent metal ions might work in concert. Here we report the first transition metal complex of type B, its unusual structural features in the solid state, and characteristics of the metal ± metal interaction in the mixed-valent form.It proved difficult to introduce the parent Cp into the side arms of functionalized pyrazole derivatives such as 1, [5] and thus we employed a ™protected∫ form of Cp: attachment of [CpMn(CO) 3 ] to the pyrazole nucleus was achieved in a [Pd(PPh 3 ) 2 ]/ZnCl 2 -catalyzed cross-coupling reaction [6] yielding 2 (Scheme 1).A single-crystal structure analysis [7] showed that 2 contains a protonated (noncoordinating) 1H-pyrazole heterocycle suitably arranged to potentially interact with the pendant Scheme 1. Synthesis of the complex K 3 À . metal carbonyl fragments. Photolytic decarbonylation of 2 and deprotonation using KOtBu gave K 3 À , the first bimetallic complex of type B. Its formation can be monitored by IR spectroscopy through the characteristic changes of the CO stretching frequencies (2015/1927 cm À1 for 2 versus 1919(1896)/1848(1816) cm À1 for 3 À ). [8] Single crystals of K 3 À ¥ 0.9 THF obtained from THF/light petroleum were analyzed by X-ray crystallography. [9] The asymmetric unit contains four (very similar) dimanganese(i) units of the anticipated constitution-one of which is depicted in Figure 1. The N-Mn-C CO angles in 3 À are rather large (mean value 101.98) compared to those in other [CpMn(CO) 2 L] complexes (L N-donor ligand; 92.6 ± 98.18 according to a CSD search), indicating a somewhat strained situation in the chelate complex 3 À . Figure 1. Molecular structure of 3 À (30 % probability ellipsoids). Selected interatomic distances [ä] and range of selected bond angles and dihedral angles [8]; values for the other three independent molecules in square brackets: Mn1-N1 2.

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“…The chemistry of dinuclear organometallic complexes containing the fulvalene (Fv) ligand has recently become a topic of renewed interest. − Besides their interesting electrochemical , and magnetic properties, the reactivities of Fv complexes should differ from those of their Cp analogues. There are at least two important reasons that suggest this difference.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Reactivity, Electrochemical Study, and Crystal Structures of (η⁵:η⁵-(C₅H₃CO₂Me)₂)Mo₂(CO)₆

Delgado¹,

Macazaga²,

Medina³

et al. 1996

Organometallics

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The reaction of a dicarbomethoxydihydrofulvalene solution with Mo(CO)6 leads to the formation of two isomers of (η5:η5-(C5H3CO2Me)2)Mo2(CO)6 (1 and 2). The X-ray structure of both compounds has been determined. Reaction of 2 with LiEt3BH yields Li2[(η5:η5-(C5H3CO2Me)2)Mo2(CO)6] (3), and this with Hg(CN)2 results in the insertion of Hg into the Mo−Mo bond giving (η5:η5-(C5H3CO2Me)2)Mo2(CO)6Hg (4). The electrochemical study of 1−4 is reported. The two-electron reduction of 1 and 2, through an ECE mechanism, leads to the dianions. This reduction takes place at a significantly less negative potential than for the unsubstituted fulvalene (η5:η5-C10H8)Mo2(CO)6 (5) due to the electron-withdrawing properties of the carbomethoxy substituents. The oxidation of 1 and 2 is also affected by the substituents, taking place at a more positive potential than 5. The reduction of 4 yields the dianion 2 2- and liberates Hg.

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Structural consequences of electron-transfer reactions. 26. Evidence for time-dependent valence detrapping in a mixed-valent dimanganese fulvalenyl cation

Cited by 69 publications

References 0 publications

Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

Bifunctional Cp∩N Complexes—Unusual Structural Features and Electronic Coupling in Highly Preorganized Bimetallic Systems

Synthesis, Reactivity, Electrochemical Study, and Crystal Structures of (η⁵:η⁵-(C₅H₃CO₂Me)₂)Mo₂(CO)₆

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Structural consequences of electron-transfer reactions. 26. Evidence for time-dependent valence detrapping in a mixed-valent dimanganese fulvalenyl cation

Cited by 69 publications

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Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

Influence of Quinoidal Distortion on the Electronic Properties of Oxidized Divinylarylene-Bridged Diruthenium Complexes

Bifunctional Cp∩N Complexes—Unusual Structural Features and Electronic Coupling in Highly Preorganized Bimetallic Systems

Synthesis, Reactivity, Electrochemical Study, and Crystal Structures of (η5:η5-(C5H3CO2Me)2)Mo2(CO)6

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Synthesis, Reactivity, Electrochemical Study, and Crystal Structures of (η⁵:η⁵-(C₅H₃CO₂Me)₂)Mo₂(CO)₆