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OLS Field Name OLS Field Data
Main Title Cobalt-59 Nuclear Magnetic Resonance Studies of Chloro-, Bromo-, and Iodo-Substituted Tris(acetylacetonato)cobalt(III) Complexes.
Author Busse, S. C. ; Abbott, E. H. ;
CORP Author New Mexico Univ., Albuquerque. School of Medicine. ;Montana State Univ., Bozeman. Dept. of Chemistry.;Environmental Research Lab.-Duluth, MN.;National Science Foundation, Washington, DC.
Publisher c1989
Year Published 1989
Report Number EPA-R-809478 ;NSF-CHE78-26160; EPA/600/J-89/013;
Stock Number PB89-236343
Additional Subjects Cobalt isotopes ; Nuclear magnetic resonance ; Relaxation time ; Cobalt halides ; Electrostatics ; Ligands ; Temperature ; Chelates ;
Holdings
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Status
NTIS  PB89-236343 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 12/18/1989
Collation 6p
Abstract
The cobalt-59 nuclear magnetic resonance spectra and longitudinal relaxation times have been studied for tris(acetylacetonato)cobalt(III) complexes with chloride, bromide, and iodide substitution at the methine carbon atom of the chelate ring. The cobalt-59 chemical shift is sufficiently sensitive to this remote substitution that cobalt-59 resonances are well resolved for each complex in a series of monohalo-, dihalo-, and trihalo-substituted complexes. The chemical shift is not linearly dependent on substitution. For the more electronegative halides, chlorine and bromine, static electric field gradient effects can be observed in the mixed-ligand complexes, but these effects amount to less than 10% of the observed relaxation rate. Through comparison of carbon-13 and cobalt-59 relaxation times it appears that in the solvents benzene, diglyme, and acetone, the cobalt-59 relaxation is a consequence of rotational reorientation, but for the solvent chloroform the cobalt-59 relaxation is different. Several possible explanations for this observation are considered. (Copyright (c) 1989 by the American Chemical Society and reprinted by permission of the copyright owner.)