Theoretical prediction of electronic spectra of uranium-containing complexes remains quite a challenge for quantum chemistry since it requires an accurate treatment of both correlation and relativistic effects at the same time. While reliable electronic excitation energies can be obtained from correlated wave function approaches that take relativistic effects into account, they are, however, li...

U 0 2 and U 3 0 8 were inhaled by baboons in amounts such that the mass concentrat ions in the lungs were between about 3 and 20, and 1 and 7.4 t imes respectively those calculated in human lungs after exposure to 1 ALI of the compounds . The results show that 1 year later : 1) the initial lung deposits of uranium retained in the chest are greater for U 0 2 than for U 3 0 8 ; 2) the ratios of t...

background: measurement of back ground concentration of uranium in drinking water is very important for many reasons, specially, for human health. the uranium concentration in drinking water in many counties is a matter of concern for clinical and radioactive poisoning. materials and methods: the uranium concentration in drinking water is determined using laser flourimatric uranium analyzer. fo...

recognize +4 and +6 as the main oxidation states for uranium and +4 as the only important oxidation state for thorium; appreciate that coordination numbers of >6 are the norm; be familiar with the main features of the chemistry of the other actinides, and appreciate the transition in chemical behaviour across the series; appreciate the importance of nitrate complexes; recognize the characterist...

A new series of substituted quinoline and pyridine derivatives 6a-h are synthesized by the coupling of hydrazide derivatives 4a-b with substituted carboxylic acids 5a-c in the presence of N,N,N’,N’-tetramethyl-o-(benzotriazol-1-yl) uranium tetrafluoroborate TBTU as a coupling agent and lutidine as a base. The newly synthesized compounds 6a–l is characterized by analytical NMR and mass spectral ...

Reaction of [(((Ad)ArO)(3)tacn)U(III)] (1) or [((Me(3)Si)(2)N)(3)U(III)] (3) with tetramethylimidazol-2-ylidene (Me(4)IMC:) yields novel N-heterocyclic carbene complexes [(((Ad)ArO)(3)tacn)U(III)(Me(4)IMC:)] (2) and [((Me(3)Si)(2)N)(3)U(III)(Me(4)IMC:)] (4). Uranium complexes 2 and 4 represent the first examples of compounds with an N-heterocyclic carbene ligand coordinated to a low-valent uran...

The bis(imido) uranium(VI)-C(5)H(5) and -C(5)Me(5) complexes (C(5)H(5))(2)U(N(t)Bu)(2), (C(5)Me(5))(2)U(N(t)Bu)(2), (C(5)H(5))U(N(t)Bu)(2)(I)(dmpe), and (C(5)H(5))(2)U(N(t)Bu)(2)(dmpe) can be synthesized from reactions between U(N(t)Bu)(2)(I)(2)(L)(x) (L=THF, x=2; L=dmpe, x=1) and Na(C(5)R(5)) (R=H, Me); these complexes represent the first structurally characterized C(5)H(5)-compounds of uraniu...