ESR study of reduced mixed ligand complexes of Ru(II): 4,4'- and 5,5'-diester bipyridines with Ru(II)
The electron spin resonance spectra for a series of reduced tris (ML/sub 3//sup (2-n)+/) and mixed ligand complexes (ML/sub 2/L'/sup (2-n)+/), where L and L' are 2,2'-bipyridine (bpy), 4,4'-dicarbethoxy-2,2'-bipyridine (4-COOEt), and 5,5'-dicarbethoxy-2,2'-bipyridine (5-COOEt), exhibit a range of behavior. The one-electron (n = 1) spectra of (Ru(bpy)/sub 2/L/sup -/)/sup +/ where L = 4-COOEt and 5-COOEt give hyperfine structure with no temperature-dependent line broadening. While the n = 1 and n = 2 reduction products of the tris RuL/sub 3//sup 2 +/ complexes exhibit a temperature-dependent S = 1/2 signal from which an activation energy for intramolecular electron hopping can be obtained, the n = 3 product does not broaden with temperature. These results are consistent with the spatially isolated localized orbital model. The ESR for the n = 4 and n = 5 reduction products of (Ru(5-COOEt)/sub 3/)/sup 2 +/ give only an S = 1/2 signal that is not temperature dependent. The n = 6 species is diamagnetic, consistent with expectation. The hyperfine splitting constants (a/sub i/) obtained from the monocomplexes indicate a small spin density at the Ru/sup 2 +/ metal center.
- Research Organization:
- North Carolina State Univ., Raleigh
- OSTI ID:
- 6087201
- Journal Information:
- J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:18; ISSN JPCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ACTIVATION ENERGY
AZINES
BIPYRIDINES
CHEMICAL REACTIONS
COMPLEXES
DATA
ELECTRON SPIN RESONANCE
ENERGY
ESTERS
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LIGANDS
MAGNETIC RESONANCE
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIDINES
RADICALS
REDUCTION
RESONANCE
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES