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Title:Multifrequency Electron Paramagnetic Resonance Spectroscopy of Group Viib Carbonyl Radicals
Author(s):Rattinger, Gail Beth
Department / Program:Chemistry
Discipline:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Chemistry, Inorganic
Abstract:Interest in organometallic 17e('-) free radical systems has increased dramatically due to their potential roles in catalytic processes. Multi-frequency electron paramagnetic resonance spectroscopy studies of (.)Mn(CO)(,3){P(n-Bu)(,3)}(,2), (.)Mn(CO)(,3){P(i-Bu)(,3)}(,2), (.)Mn(CO)(,3){P(i-Pr)(,3)}(,2') (.)Mn(CO)(,3){P(O-i-Pr)(,3)}(,2) and (.)Re(CO)(,3){P(cy)(,3)}(,2) (cy = cyclohexyl) were performed at conventional X-band ((DBLTURN) 9 GHz), S-band ((DBLTURN) 3 GHz) and L-band ((DBLTURN) 1 GHz) frequencies. Computer simulations of the X- and S-band frozen solution spectra as well as room temperature X-band solution spectra were obtained. Anisotropic g-shifts, metal hyperfine, and phosphorus super-hyperfine spin Hamiltonian parameters are reported and compared to values reported for (.)Mn(CO)(,5).
A perturbation treatment is developed and used in the interpretation of the anisotropic metal center parameters obtained for these square pyramidal d('7) systems. Information about the distribution of unpaired spin density is obtained. Variation of ligand steric and electronic parameters does not drastically vary the amount of unpaired spin density in the manganese 3d(,z)('2) orbital. Only a small percentage of unpaired spin density is found to be delocalized onto the phosphorus ligands. Upper and lower limits of core polarization as well as the energy difference, (DELTA)E, between the ground state and d(pi) excited state are estimated. Kinetics implications are discussed.
Issue Date:1984
Type:Text
Description:244 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
URI:http://hdl.handle.net/2142/70281
Other Identifier(s):(UMI)AAI8502277
Date Available in IDEALS:2014-12-15
Date Deposited:1984


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