Uranyl-containing compounds

It is well-known that many organic excited states (e.g. the triplet state of benzophenone) can effectively abstract hydrogen atoms from organic compounds such as alkanes and alcohols. This behaviour is not commonly found for metal-containing compounds - a notable exception being the lowest excited state of uranyl ion which abstracts H atoms from alcohols, sugars etc., with the resultant formation of free radicals and U(V) compounds. Recent work has shown that it is very effective in inducing strand breaks in DNA (see Sect. 8). 

After irradiation with 3.3 MGy of a DCH18C6 solution in 1 mol L 1 nitric acid containing 20 g I. of uranyl nitrate, compounds 2 and 4 (presented in Figure 8.15 with their radiolytic yields) were shown to be the main products of radiolysis nevertheless, 50% of DCH18C6 remained unchanged. In these conditions, the disappearance yield G(-DCH18C6) was estimated to be 0.72 molecule/100 eV (7). 

Uranium trioxide is slightly basic, but with the exception of uranium hexafluoride, the salts formed by interaction with acids still contain two-thirds of its oxygen in the form of the uranyl radical, compounds of the type UOjR g being produced. On the other hand, however, the oxide acts towards strong bases as an acid anhydride, similar to chromic anhydride, and produces stable uranates. In contact with water it readily forms uranic acid, U02(0H)2. ... 

The structure of PbU02(Se03)2 contains two-dimensional uranyl selenite sheets that are substantially different than those found in other uranyl selenite compounds. The selenite ligands chelate and bridge between uranyl moeities. 

Figure 1 The francevillite anion topology (a) and the uranyl vanadate layers in camotite-type compounds (b) layer P in hT-, or 1,3-diaminopropane- containing compounds (c) layer P in ethylenediamine- and 1,4-dimithylpiperazine- containing compounds.

Emanations from radioactive substances affect photographic plates just as ordinary visible light does. Becquerel s discovery of radioactivity resulted from the unexpected exposure of such a plate, wrapped in black paper, by a nearby enclosed sample of a uranium-containing compound, potassium uranyl sulfate. After a photographic plate has been developed and fixed, the intensity of the exposed spot is related to the amount of radiation that struck the plate. Quantitative detection of radiation by this method is difficult and tedious. 

A variety of molecular patterns occur in uranyl oxalate compounds. Apart from the simple uranyl oxalate trihydrate, four other oxalate compounds containing the uranyl ion have been synthesized and their structures investigated. 

Summary of Reaction Conditions Employed in Attempts to Complex the Uranyl Ion with Sulfonate and Sulfate Containing Compounds... 

During primary wall formation the plastids contain starch and other materials which stain heavily with uranyl acetate and lead citrate. When the tracheid starts to form the Si layer, the plastid becomes surrounded by an endoplasmic reticulum. While the fate of these compounds is unknown, it can be envisaged that they are used for generation of energy and/or a source of cell wall materials. 

The dioxouranium(VI), or uranyl, ion is peculiar in forming two 8-quinolinol derivatives. Only the red crystalline compound containing an added mol of 8-quinolinol can be prepared by direct precipitation. This material has been recommended for the accurate determination of uranium-(VI)1,3,6,7 because of its insolubility, constancy of composition, ease of drying, and large molecular weight. 

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