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|Title:||Part I. Synthesis of Polyoxoanion Supported Organoactinides. Part Ii. Surface Oxygen Reactivity in Decavanadate|
|Author(s):||Maltbie, David John|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Part I. The MW(,5)O(,19)('3-) anions, M = Nb and Ta react with (C(,5)H(,5))(,3)- AcCl, Ac=Th and U, to form 2:1 polyoxoanion to actinide adducts. According to a single crystal X-ray diffraction study of (C(,5)H(,5))(,3)U- (NbW(,5)O(,19))(,2) (n-C(,4)H(,9))(,4)N (,5), IR spectroscopy, and ('17)O NMR spectros- copy, all four adducts contain MW(,5)O(,19)('3-) ligands which coordinate to the metal center as unidentate ligands through terminal OM oxygens. ('1)H(' )NMR and labeling studies were used to show that the actinide - oxygen bonds in these adducts are quite labile.
Reaction of the MW(,5)O(,19)('3-) anions with (C(,5)H(,5))(,3)Ac(NCCH(,3))(,2)('+) cati- ons resulted in the formation of 1:1 polyoxoanion to actinide adducts. ('17)O(' )NMR spectroscopic studies of the (C(,5)H(,5))(,3)Ac(MW(,5)O(,19)) ('2-) anions revealed that, like the 2:1 adducts, the MW(,5)O(,19)('3-) ligands in the 1:1 adducts bind to the actinide center through a terminal OM oxygen.
A thermally and kinetically stable polyoxoanion-supported organoactinide, (C(,5)H(,5))(,2)U(TiW(,5)O(,19)) (,2)('4-), was isolated from the reaction of (C(,5)H(,5))(,3)UCl and ClTiW(,5)O(,18)('3-) in refluxing CH(,3)CN. An X-ray diffraction study performed by Professor Victor W. Day at the University of Nebraska showed that this anion contained TiW(,5)O(,19)('4-) ligands which were bound to one uranium center through a terminal OTi and a bridging OTiW oxygen, and to the other uranium center through a terminal OTi oxygen. Variable temperature ('17)O NMR spectroscopy and ('18)O label crossover experiments were used to demonstrate that this anion undergoes a fluxional process in CH(,3)CN solution, and a mechanism for this process was proposed.
Part II. Selective metal decoupling was used in an ('17)O ('51)V NMR study of aqueous Na(,6)V(,10)O(,28) solutions to unambiguously assign all resonances in the fully resolved ('17)O and ('51)V decavanadate NMR
spectra. These assignments were then used in a study which deter- mined the protonation sites in the H(,3)V(,10)O(,28)('3-) anion in the solid state
and in CH(,3)CN solution. An X-ray crystallographic study of H(,3)V(,10)O(,28)- (C(,6)H(,5))(,4)P (,3) determined that the solid state protonation sites were
triply and double bridging oxygens by crystallographically locating the protons associated with the anion. The same protonation sites
were found in CH(,3)CN solution for the anion in H(,3)V(,10)O(,28) (n-C(,4)H(,9))(,4)N (,3) using dynamic ('17)O NMR spectroscopy.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-15|