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Electron Paramagnetic Resonance Investigation of Some 11‐Tungstoruthenate(III) Polyoxoanions
Author(s) -
Rong Charles C.,
So Hyunsoo,
Pope Michael T.
Publication year - 2009
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200900578
Subject(s) - chemistry , ruthenium , electron paramagnetic resonance , ligand (biochemistry) , unpaired electron , ligand field theory , hyperfine structure , atomic orbital , pyridine , crystallography , paramagnetism , molecular orbital , stereochemistry , nuclear magnetic resonance , electron , medicinal chemistry , molecule , atomic physics , ion , biochemistry , physics , receptor , organic chemistry , quantum mechanics , catalysis
EPR spectra of three Keggin structure polyoxotungstates containing ruthenium(III), [PW 11 O 39 Ru(L)] 4– (L = H 2 O, pyridine, dimethyl sulfoxide), have been recorded at 77 K and yield details of the symmetry and ligand field parameters of the embedded low‐spin d 5 ruthenium cation. The magnitudes of the g tensors and 99,101 Ru hyperfine coupling constants of the dmso derivative show that the unpaired electron occupies a d xy ‐type orbital as a result of the axial component of the ligand field with Δ(d xy – d xz ,d yz ) ≈ 6200 cm –1 . A weak broad absorption in the electronic spectrum at ca. 5600 cm –1 is consistent with this interpretation. A smaller rhombic component imposed by the polytungstate ligand further splits the d xz and d yz orbitals (< 2000 cm –1 ). The orbital reduction factor k of the dmso complex (0.69) is significantly smaller than those for the aqua and pyridine derivatives (0.80, 0.83), and this implies that, as previously found for the Ru II analog, the dmso ligand is S ‐bonded in the Ru III complex.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)