| The chemistry of the P73− and [P 7W(CO)3]3− ions has been investigated. The novel compound, [K(2,2,2-)]2[(cyclohexyl)3SnP 7W(CO)3], has been prepared and fully characterized. Through extensive solution studies including 1H, 13C, and variable temperature 31P NMR, it was determined that [(cyclohexyl) 3SnP7W(CO)3]2− undergoes pyramidal inversion at phosphorus. The ΔG‡ value of this process was calculated to be 18.5 kcal/mol. Another solution study systematically examined the basicity of the P73− and [P7W(CO)3]3− ions. The phosphorous cage of [P7W(CO)3]3− ions is highly nucleophilic as shown by its high reactivity with weak electrophiles, however, only moderate basicity is observed. In these studies, reactions to protonate the P73− ion were unsuccessful at room temperature but the pKa value for [P7W(CO)3]3− in dimethylsulfoxide was determined to be in the range 17.9–22.6.; The coordination chemistry of uranium has been investigated through the preparation of novel compounds. Acidic solutions of UO2(C 2H3O2)2·2H2O, alkali metals, halides, and crown ethers reacted to give the sandwich-type compounds [K(18-crown-6)]2[UO2Cl4] (1), [K(18-crown-6)]2[UO2Br4] (2), [Na(15-crown-5)]2[UO2Cl4] (3), [Na(15-crown-5)]2[UO2Br4] (4), [Li(12-crown-4)]2[UO2Cl4] (5), and [Li(12-crown-4)]2[UO2Br4] (6). In all six cases, the resulting structure consists of a [UO2X 4]2− ion sandwiched between two [A(crown)] + ions. A systematic, structural study has been performed evaluating the effect of the alkali metal/halide on the coordination geometry of [UO 2X4]2− to the metallated crown ether cation. The [UO2X4]2− ions coordinate to two [A(crown)]+ cations through four halides (1, 2), through two halides (3), through the two uranyl oxygens and two halides (3, 4) or through the two uranyl oxygen atoms only (5, 6). The six compounds were characterized by single crystal X-ray diffraction, powder diffraction, elemental analysis, IR and Raman spectroscopy. The structural trends identified are consistent with the classical principles of hard-soft acid-base (HSAB) theory.; Four novel uranium phosphate compounds have been prepared and characterized by single crystal X-ray diffraction, as well as IR and Raman spectroscopy techniques. Through traditional aqueous solution routes, [UO2(H 2PO4)2(H2O)]2·(18-crown-6)·5H 2O, UO2(H2PO4)2(H2 O)·(18-crown-6)·3H2O, and U2(HPO 4)2(H2PO4)2(μ 2-C2O4)(H2O)2)·2H 2O have been isolated and their structures determined. Hydrothermal synthesis produced the first structurally characterized example of an organically templated open-framework uranium phosphate, [(C2H5) 2<... |
