THE STUDY OF COMPLEXES OF HETEROCYCLIC BASES BY ULTRAVIOLET PHOTOELECTRONSPECTROSCOPY.
Item
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Title
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THE STUDY OF COMPLEXES OF HETEROCYCLIC BASES BY ULTRAVIOLET PHOTOELECTRONSPECTROSCOPY.
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Identifier
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AAI8103928
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identifier
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8103928
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Creator
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GIN, ALLEN WILLIAM.
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Contributor
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Michael Weiner
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Date
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1980
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Inorganic
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Abstract
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The UV photoelectron spectra of Cr(CO)(,5).L, BH(,3).L and BF(,3).L (where L = 4-substituted pyridine) were measured, and the ionization potentials observed below 12 eV are discussed. For Cr(CO)(,5).L, bands found in the region 7-8 eV are assigned to ionization from the d-orbitals. The IP values increase with the increasing electron acceptor nature of the ring substituents. The remaining bands below 12 eV are assigned to the pyridine orbitals. The IP values of the uncomplexed pyridine increase on complexation, and a comparison is made of the effects of complexation with the CR(CO)(,5) and BH(,3) moieties. MNDO calculations were utilized to explain the increases in a(,2) ((pi)) and b(,1) ((pi)) energies upon borane and boron trifluoride complexation. The increase in a(,2) ((pi)) upon adduct formation can be related to changes in charge densities. Symmetry conditions prevent orbital interactions between the a(,2) ((pi)) and (pi) components of the acid or substituent. Since the b(,1) ((pi)) orbital can be perturbed by orbital interactions, a simple explanation for the energy changes of b(,1) ((pi)) upon complexation is not possible.;The ionization potentials of symmetric and unsymmetric tetraalkyltin compounds (R(,4)Sn, RSnMe(,3) and R(,2)SnMe(,2); R = alkyl groups) are correlated linearly with the sum of the Taft (sigma)('*) values ((SUMM)(sigma)('*)) for the alkyl ligands only if the weighted average IP values are used. This takes into account the orbital degeneracy of the lowest energy bands in the photoelectron spectra.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Chemistry
