ESR Spectrum of 2,2′ Dipyridyl-Na Complex

Zahlan, A. B.; Heineken, F. W.; Bruin, M.; Bruin, F.

doi:10.1063/1.1701406

Cited by 21 publications

(4 citation statements)

References 2 publications

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“…In fluid solution, 2 + is close to EPR silent. This together with the unresolved EPR spectrum of the solid sample unfortunately precludes a more detailed analysis of the spin density distribution within the CHCH-bipy-CHCH bridge by comparing the 14 N or 1 H hyperfine splittings (hfs) to those of authentic bipy – radical anions. − Considering the rather small magnitudes of the hfs constants in bipy – , the additional 31 P and 99/101 Ru hfs expected in 2 + and the overall broadening of the EPR signal in the solid or the low intensity of the EPR signal in fluid solution it is, however, not wholly surprising to see only an unresolved EPR signal for that species.…”

Section: Resultsmentioning

confidence: 99%

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

et al. 2015

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We report here on ruthenium alkenyl complexes 2 and 3 derived from 2,2'-bipyridine and their Re(CO)3X adducts 4a,b and 5. Detailed electrochemical studies on these complexes and spectroscopic characterization of their oxidized forms by IR, UV/vis/NIR, and electron paramagnetic resonance spectroscopies as well as quantum chemical studies reveal sizable (bridging) ligand contributions to the redox orbitals. Engagement of the free bipy functions of complexes 2 and 3 in binding to the electron-withdrawing fac-Re(CO)3X (X = Br, Cl) moiety enhances the metal-to-ligand charge-transfer character of the optical excitations, causes sizable anodic shifts of the redox potentials, and decreases the number of observable anodic redox waves by one when compared to complexes 2 and 3. Despite the decreasing electron density at the terminal or bridging alkenyl bipyridine ligand, the anodic redox processes still maintain appreciable ligand character as is seen by the shifts of the Ru(CO) and Re(CO)3 stretching frequencies on oxidation. Binding of the fac-Re(CO)3X moiety also attenuates the degree of ground-state delocalization in the mixed-valent states.

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Section: Resultsmentioning

confidence: 99%

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

et al. 2015

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“…Thus the nitrogen spin density is given by eq. 3. Since carbon 2 is situated Px = 0.254 -(p7c + p2c) (3) between atoms of fairly large positive spin densities, the possibility exists that p2c is negative.26 Thus while the (23) The notation p,-c indicates spin density on the carbon atom at the ith position (see Figures 4 and 5).…”

Section: Resultsmentioning

confidence: 99%

An Electron Spin Resonance Study of the Anion Radicals of 9,10-Diazaphenanthrene, 2,2'-Bipyrimidine, and Δ^2,2'-Biisobenzimidazolylidene

Geske¹,

Padmanabhan²

1965

J. Am. Chem. Soc.

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“…The triple-ζ STO atomic basis set was augmented with a 2p polarization function for H, a 3d polarization function for C, N, and P, and a 5p polarization function for Ru. We have used the two (meta-)hybrid functionals B3LYP ,,, and PBE0 , and one meta-hybrid functional M06-2X , to evaluate magnetic coupling constants. In that case, an all-electron basis set was necessary.…”

Section: Methodsmentioning

confidence: 99%

Ruthenium Carbon-Rich Group as a Redox-Switchable Metal Coupling Unit in Linear Trinuclear Complexes

et al. 2017

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The preparation and properties of novel ruthenium carbon-rich complexes [(Ph-C≡C-)Ru(dppe)(-C≡C-bipyM(hfac))] (n = 1, 2; M = Cu, Mn; bipy = 2,2'-bipyridin-5-yl) characterized by single-crystal X-ray diffraction and designed for molecular magnetism are reported. With the help of EPR spectroscopy, we show that the neutral ruthenium system sets up a magnetic coupling between two remote paramagnetic Cu units. More specifically, these copper compounds are unique examples of bimetallic and linear heterotrimetallic compounds for which a complete rationalization of the magnetic interactions could be made for exceptionally long distances between the spin carriers (8.3 Å between adjacent Cu and Ru centers, 16.6 Å between external Cu centers) and compared at two different redox states. Surprisingly, oxidation of the ruthenium redox-active metal coupling unit (MCU), which introduces an additional spin unit on the carbon-rich part, leads to weaker magnetic interactions. In contrast, in the simpler parent complexes bearing only one paramagnetic metal unit [Ph-C≡C-Ru(dppe)-C≡C-bipyCu(hfac)], one-electron oxidation of the ruthenium bis(acetylide) unit generates an interaction between the Cu and Ru spin carriers of magnitude comparable to that observed between the two far apart Cu ions in the above corresponding neutral trimetallic system. Evaluation and rationalization of this coupling with theoretical tools are in rational agreement with experiments for such complex systems.

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ESR Spectrum of 2,2′ Dipyridyl-Na Complex

Cited by 21 publications

References 2 publications

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

An Electron Spin Resonance Study of the Anion Radicals of 9,10-Diazaphenanthrene, 2,2'-Bipyrimidine, and Δ^2,2'-Biisobenzimidazolylidene

Ruthenium Carbon-Rich Group as a Redox-Switchable Metal Coupling Unit in Linear Trinuclear Complexes

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ESR Spectrum of 2,2′ Dipyridyl-Na Complex

Cited by 21 publications

References 2 publications

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

Vinyl Ruthenium-Modified Biphenyl and 2,2′-Bipyridines

An Electron Spin Resonance Study of the Anion Radicals of 9,10-Diazaphenanthrene, 2,2'-Bipyrimidine, and Δ2,2'-Biisobenzimidazolylidene

Ruthenium Carbon-Rich Group as a Redox-Switchable Metal Coupling Unit in Linear Trinuclear Complexes

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An Electron Spin Resonance Study of the Anion Radicals of 9,10-Diazaphenanthrene, 2,2'-Bipyrimidine, and Δ^2,2'-Biisobenzimidazolylidene