Mixed-Valence Properties of an Acetate-Bridged Dinuclear Ruthenium (II,III) Complex
(2003) In The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory 107(22). p.4373-4380- Abstract
- The mixed-valence dinuclear ruthenium complex [Ru2(bpmp)(-OAc)2]2+ (where bpmp is the phenolate anion of 2,6-bis[bis(2-pyridylmethyl) aminomethyl]-4-methylphenol, H-bpmp) has been studied by UV-Vis-NIR, IR, and EPR spectroscopic and electrochemical techniques. The Ru2II,III complex undergoes reversible one-electron reduction (E1/2 = -0.61 V vs Fc+/0) and oxidation (E1/2 = 0.09 V vs Fc+/0), resulting in the Ru2II,II and Ru2III,III complexes, respectively. A comproportionation constant of Kc = 1.10 × 1012 (Gc = -68 kJ mol-1) indicates considerable stability of the mixed-valence state. The paramagnetic complex displays a rhombic EPR spectrum (g1 = 2.492; g2 = 2.242; g3 = 1.855) arising from a ground state in a S = 1/2 low spin system in a low... (More)
- The mixed-valence dinuclear ruthenium complex [Ru2(bpmp)(-OAc)2]2+ (where bpmp is the phenolate anion of 2,6-bis[bis(2-pyridylmethyl) aminomethyl]-4-methylphenol, H-bpmp) has been studied by UV-Vis-NIR, IR, and EPR spectroscopic and electrochemical techniques. The Ru2II,III complex undergoes reversible one-electron reduction (E1/2 = -0.61 V vs Fc+/0) and oxidation (E1/2 = 0.09 V vs Fc+/0), resulting in the Ru2II,II and Ru2III,III complexes, respectively. A comproportionation constant of Kc = 1.10 × 1012 (Gc = -68 kJ mol-1) indicates considerable stability of the mixed-valence state. The paramagnetic complex displays a rhombic EPR spectrum (g1 = 2.492; g2 = 2.242; g3 = 1.855) arising from a ground state in a S = 1/2 low spin system in a low symmetry environment. Three intense, distinguishable intervalence bands are observed in the NIR to mid-IR spectrum of [Ru2(bpmp)(-OAc)2]2+ at 3765 cm-1 ( = 1840 M-1cm-1), 5615 cm-1 ( = 10590 M-1cm-1 ), and 7735 cm-1 ( = 3410 M-1cm-1). All intervalence bands are symmetric but more narrow than predicted for the classical limit and independent of solvent polarity. The results of the spectroscopic and electrochemical characterization indicate that [Ru2(bpmp)(-OAc)2]2+ is either electronically delocalized (class III, Hab = 1880 cm-1) or at the borderline between localization and delocalization (class II-III, Hab 590 cm-1) with rapid electron transfer (kET > 4 × 1012 s-1) decoupled from solvent reorientation but with a residual activation barrier (Ea 440 cm-1) from inner reorganization. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/124683
- author
- Lomoth, Reiner ; Magnusson, Ann LU ; Xu, Yunhua and Sun, Licheng
- organization
- publishing date
- 2003
- type
- Contribution to journal
- publication status
- published
- subject
- in
- The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
- volume
- 107
- issue
- 22
- pages
- 4373 - 4380
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000183223300007
- scopus:0038511085
- ISSN
- 1520-5215
- DOI
- 10.1021/jp022563y
- language
- English
- LU publication?
- yes
- id
- c76dcbf4-8d39-4d67-8e7e-c3821e3bdb35 (old id 124683)
- date added to LUP
- 2016-04-01 16:20:15
- date last changed
- 2022-01-28 19:01:18
@article{c76dcbf4-8d39-4d67-8e7e-c3821e3bdb35, abstract = {{The mixed-valence dinuclear ruthenium complex [Ru2(bpmp)(-OAc)2]2+ (where bpmp is the phenolate anion of 2,6-bis[bis(2-pyridylmethyl) aminomethyl]-4-methylphenol, H-bpmp) has been studied by UV-Vis-NIR, IR, and EPR spectroscopic and electrochemical techniques. The Ru2II,III complex undergoes reversible one-electron reduction (E1/2 = -0.61 V vs Fc+/0) and oxidation (E1/2 = 0.09 V vs Fc+/0), resulting in the Ru2II,II and Ru2III,III complexes, respectively. A comproportionation constant of Kc = 1.10 × 1012 (Gc = -68 kJ mol-1) indicates considerable stability of the mixed-valence state. The paramagnetic complex displays a rhombic EPR spectrum (g1 = 2.492; g2 = 2.242; g3 = 1.855) arising from a ground state in a S = 1/2 low spin system in a low symmetry environment. Three intense, distinguishable intervalence bands are observed in the NIR to mid-IR spectrum of [Ru2(bpmp)(-OAc)2]2+ at 3765 cm-1 ( = 1840 M-1cm-1), 5615 cm-1 ( = 10590 M-1cm-1 ), and 7735 cm-1 ( = 3410 M-1cm-1). All intervalence bands are symmetric but more narrow than predicted for the classical limit and independent of solvent polarity. The results of the spectroscopic and electrochemical characterization indicate that [Ru2(bpmp)(-OAc)2]2+ is either electronically delocalized (class III, Hab = 1880 cm-1) or at the borderline between localization and delocalization (class II-III, Hab 590 cm-1) with rapid electron transfer (kET > 4 × 1012 s-1) decoupled from solvent reorientation but with a residual activation barrier (Ea 440 cm-1) from inner reorganization.}}, author = {{Lomoth, Reiner and Magnusson, Ann and Xu, Yunhua and Sun, Licheng}}, issn = {{1520-5215}}, language = {{eng}}, number = {{22}}, pages = {{4373--4380}}, publisher = {{The American Chemical Society (ACS)}}, series = {{The Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory}}, title = {{Mixed-Valence Properties of an Acetate-Bridged Dinuclear Ruthenium (II,III) Complex}}, url = {{http://dx.doi.org/10.1021/jp022563y}}, doi = {{10.1021/jp022563y}}, volume = {{107}}, year = {{2003}}, }