Two copper-uranium heterometallic compounds, [(UO2)3Cu(II)O2(C6NO2)5] (1) and [(UO2)Cu(I)(C6NO2)3] (2), have been synthesized by the reaction of uranyl acetate with copper salts in the presence of isonicotinic acid. Both compounds have been characterized by single-crystal X-ray diffraction, IR, Raman, and UV-vis spectroscopy. In compound 1, interactions between copper and uranium centers occur and result in a three-dimensional pillar layered structure. Compound 1 is also the first example of a heterometallic uranyl organic framework with a trinuclear U3O18 building block. Compound 2 is the first uranyl organic framework that contains monovalent copper, which arises from the reaction of Cu(II) chloride and is assumed to be due to the oxidation of chloride at low pH.

Molecular hydrogen is a primary product of the interaction of low-LET (γ, β) radiation with water, and previous measurements have shown that its initial yield increases at elevated temperature. This has been the subject of controversy because more atomic H and (e(-))aq free radicals escape recombination at elevated temperature, and the corresponding production of H2 should decrease. Room temperature experiments have demonstrated that a large fraction of H2 also comes from early physicochemical processes (presumably electron-hole charge recombination and/or dissociative electron attachment), which can be suppressed by scavenging presolvated electrons. In the present work we extend these scavenging measurements up to 350 °C to investigate why the H2 yield increases. We find that most of the H2 yield increase is due to the "presolvation" processes. Relatively small changes in the scavenging efficiency vs LET, and a significant effect of temperature depending on the (positive or negative) charge of the scavenger, indicate that the presolvation H2 is dominated by electron-hole charge recombination rather than dissociative electron attachment at all temperatures.

Low Linear Energy Transfer (LET) radiolysis escape yields (G values) are reported for the sum (G(H) + G(e-) aq) and for G(H 2) in subcritical water up to 350 o C. The scavenger system 1-10 mM acetate/0.001M hydroxide/0.00048M N 2 O was used with simultaneous mass spectroscopic detection of H 2 and N 2 product. Temperature-dependent measurements were carried out with 2.5MeV electrons from a van de Graaff accelerator, while room temperature calibration measurements were done with a 60 Co gamma source. The concentrations and dose range were carefully chosen so that initial spur chemistry is not perturbed and the N 2 product yield corresponds to those reducing radicals that escape recombination in pure water. In comparison with a recent review recommendation of Elliot and Bartels (AECL report 153-127160-450-001, 2009), the measured reducing radical yield is seven percent smaller at room temperature but in fairly good agreement above 150 o C. The H 2 escape yield is in good agreement throughout the temperature range with several previous studies that used much larger radical scavenging rates. Previous analysis of earlier high temperature measurements of G esc (OH) is shown to be flawed, although the actual G values may be nearly correct. The methodology used in the present report greatly reduces the range of possible error and puts the high temperature escape yields for low-LET radiation on a much firmer quantitative foundation than was previously available.

Abstract. In calcite and aragonite, -irradiated at 77 K, several paramagnetic centers were generated and detected by EPR spectroscopy; in calcite, CO 3 -(orthorhombic symmetry, bulk and bonded to surface), CO 3 C more detailed information about the formed radicals was possible to be obtained. In both natural (white coral) and synthetic aragonite the same radicals were identifi ed with main differences in the properties of CO 2 -radicals. An application of Q-band EPR allowed to avoid the signals overlap giving the characteristics of radical anisotropy.

Gamma irradiated synthetic hydroxyapatite, bone substituting materials NanoBone(®) and HA Biocer were examined using EPR spectroscopy and compared with powdered human compact bone. In every case, radiation-induced carbon centered radicals were recorded, but their molecular structures and concentrations differed. In compact bone and synthetic hydroxyapatite the main signal assigned to the CO(2) (-) anion radical was stable, whereas the signal due to the CO(3) (3-) radical dominated in NanoBone(®) and HA Biocer just after irradiation. However, after a few days of storage of these samples, also a CO(2) (-) signal was recorded. The EPR study of irradiated compact bone and the synthetic graft materials suggest that their microscopic structures are different. In FT-IR spectra of NanoBone(®), HA Biocer and synthetic hydroxyapatite the HPO(4) (2-) and CO(3) (2-) in B-site groups are detected, whereas in compact bone signals due to collagen dominate.