Uranium derivative

Because of the high temperatures involved in magmatic- and metasomatic-related uranium deposits, variations in their 238y 23Sy pg jgg should be minimal, unless later alteration has resulted in mobilization of uranium. The calcrete deposits measured so far (Fig. 1) are known to have uranium derived from a near-by igneous source, and they have... 

Nearly all the methods described in Chapter 2 have been applied for the preparation of uranium derivatives. The reaction of metallic uranium with alcohols in the presence of halogenes (method 1) doesn t lead, as it turned out, to homoleptic alkoxides, but is a facile route to alkoxide halides [79, 1669] ... 

Figure 5.8 Tra-cyclopentadienyl uranium derivative chemistry. (From Ref. 263, with permission.)...

Ullmann synthesis, ] 15 Unsaturated acid chlorides, acylation, 49 Uranium derivatives, 154 Uranyl ions, 108 Urea, with azothiazoles. 111 to thiazolyl urea, 56 see also Thiazolyl urea Urine, 2-aminothiazoles in, 85 metabolite in, 85... 

Most pyrazole complexes are inert to moist air, with only the silver and gold compounds 206 and 207 showing limited stability 178). The X-ray structures of the unsubstituted thorium and uranium derivatives 209a and 210a, which are isostructural, have been reported 280). The hexafluoro-acetonylpyrazole complexes are listed in Table IX. 

Another constraint on the origin of the xenon now found in the upper mantle is obtained from the composition of fissiogenic Xe. In a closed-system reservoir, plutonium-derived Xe will dominate over uranium-derived Xe (see Section 4.11.3.2). In a system that has been closed throughout solar system history and starting with a chondritic ratio of... 

The iodide complexes are somewhat less stable, and well-characterized examples exist only for thorium, protactinium, and uranium. The thorium and uranium derivatives can be coveniently prepared by the reaction of iodine and metal, while protactinium tetraiodide is generated by reduction of Pals. The molecular structure of Thl4 has been examined the metal lies within a distorted square antiprism of iodide ions. 

Nevertheless, the existence of biscyclooctatetraenyl metal complexes, bonded via the metal f-orbitals and the aromatic 7r-systems of the rings, was first predicted on the basis of Wolfsberg-Helmholz MO calculations by Fischer (7) in 1963, who treated the then hypothetical U(Cot)2 molecule, and demonstrated experimentally by Streit-wieser and Miiller-Westerhoff (8) in 1968. These authors succeeded in synthesising the uranium derivative, U(Cot)2, and gave to it the trivial name, uranocene, in order to underline its resemblance to the d-series metallocenes both structurally and, as they proposed, in its mode of metal-ring bonding. 

Camphene condensed with methyl propiolate under the influence of Lewis acids to give spiro-cyclobutene derivatives525 and with PCl2Me-AlCl3 to form C-3—C-8 bridged phosphorus adducts.526 Isocamphan-10-al condensed with rhodanine to yield a fungicidal product.527 Camphenyl-lithium can readily be converted into the tetra-alkyl-chromium or -uranium derivatives.528... 

However, despite the fact that in the natmal state the Navajo are mostly free from cancer, there are tragic uranium-derived consequences for the Navajos and other tribes, and for their land and water and also for others who have lived and worked around the manium mines and mine tailings, near test sites, and at the Los Alamos National Laboratory (LANL). These facts are amplified at a personal... 

Actinides, especially thorium and uranium derivatives, found some uses in organic synthesis. For some details see in (5,6). Organometallic chemistry of thorium and uranium is undergoing rapid and give good hope to lead to useful application in catalysis. 

The compound UCp3(C3H3N2) (C3H3N2 = pyrazolate anion) was synthesized (30) with the expectation of forming a dimeric organo-uranium derivative. This was based on the known coordination behavior of the ligand in transition metal chemistry where it is almost exclusively exo-bidentate. The structure of the molecule is shown in Fig. 10 and reveals a novel n -endo-bidentate bonding mode for the... 

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