ISSN:
0749-1581
Keywords:
Electron paramagnetic resonance
;
Electron spin resonance
;
Metal carbonyl radical
;
Iron-tungsten carbonyl
;
Unpaired electron
;
g Matrix
;
Odd-electron carbonyl
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Single crystals of PPN+HFeW(CO)9- prepared from THF · W(CO)5 and PPN+HFe(CO)4- exhibit weak single-line EPR spectra corresponding to the presence of two paramagnetic impurities. One of the spectra increases in intensity by an order of magnitude on 60Co γ-irradiation. The g2 matrices for both species in an orthogonal crystal-axis system were assembled from measurements of g values made at 77 K on crystallographically oriented samples. The intense spectrum has principal g values of 2.0064, 2.0468 and 2.1320 and principal directions of g which lie close to bonds emanating from the Fe nucleus of the undamaged anion. Consideration of the principal g values and directions for this species leads to an assignment to a FeW(CO)9- radical in which the unpaired electron is principally located in a Fe 3dz2 orbital directed along the Fe—H bond of the host anion. The other signal has principal g values (2.0229, 2.0425, 2.0950) close to those established for the singly bridged isomer of Fe2(CO)8-, but their directions do not correlate well with bond directions within the host anion. It is concluded that small amounts of the persistent Fe2(CO)8- radical generated in the preparative procedures substitute for the host anion in the crystals of PPN+HFeW(CO)9-.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260290512
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