Binucleating multidentate amine bis(phenolate) ligands with rigid terphenyl backbones were designed to support two zirconium centers locked in close proximity. Polymerizations of propylene or 1-hexene with the synthesized bimetallic precatalysts resulted in polymers with significantly higher isotacticity (up to 79% mmmm) in comparison to the stereoirregular polymers produced with previously rep...

New azanucleosides were obtained using sulphated zirconia (ZS) as catalyst in the nucleophilic oxirane ring opening reaction of 1-allyl-3-(oxiran-2-ylmethyl) pyrimidine-2,4(1H,3H)-dione and 1-allyl-5-methyl-3-(oxiran-2-ylmethyl)-pyrimidine-2,4(1H,3H)-dione, with (S)-prolinol. The new templates were obtained with good yields following a route which exploits the reactivity of epoxides in the pres...

AIMS To report the appearances of zirconium dioxide and barium sulphate in interface membranes, synovium, and other tissues around joint prostheses. METHODS Histological sections from 23 specimens were reviewed by light microscopy and polarisation. Scanning electron microscopy and x ray microanalysis were performed on routinely processed paraffin wax sections. RESULTS Polyethylene, metals, ...

The mechanical properties and good biocompatibility of zirconium and some of its alloys make these materials good candidates for biomedical applications. The attractive in vivo performance of zirconium is mainly due to the presence of a protective oxide layer. In this preliminary study, the surface of pure zirconium modified by anodisation in acidic media at low potentials to enhance its barrie...

Recent concepts for nuclear fuel and targets for transmuting long-lived radionuclides (minor actinides) and for the development of innovative Gen-IV nuclear fuel cycles imply fabricating host phases for actinide or mixed actinide compounds. Cubic stabilized zirconia (Zr, Y, Am)O(2-x) is one of the mixed phases tested in transmutation experiments. Wet chemical routes as an alternative to the pow...

Title of Document: Synthesis, Stability, and Reactivity of High Oxidation State Pentamethylcyclopentadienyl Acetamidinate β-Hydrideor β-Methide-Bearing Alkyl Complexes of Zirconium, Titanium, and Tantalum Albert Epshteyn, Doctor of Philosophy, 2006 Directed By: Professor Lawrence R. Sita Department of Chemistry and Biochemsitry University of Maryland, College Park, MD 20740 In the course of stu...

A bifunctional imidazolium functionalized zirconium metal-organic framework (Zr-MOF), (I-)Meim-UiO-66 (2), was successfully prepared from the imidazole-containing Zr-MOF Im-UiO-66 (1) by a post-synthetic modification (PSM) method. It was found that the crystal size and pore features of the imidazole-containing 1 could be tuned at the nanoscale. The bifunctional MOF 2, containing Brønsted acid s...

A 51 yr old, nonsmoking female suffered from relapsing progressive pneumonia for several years. The patient had worked for 16 yrs in the nuclear industry and was exposed to grinding particles and welding fumes working with zirkaloy, an alloy containing tin, iron, chromium and zirconium. During an exacerbation of the pneumonia radiography of the lung showed interstitial infiltrations of both low...

Two new intercalates of tris[4-(pyridin-4-yl)phenyl]amine (TPPA) with zirconium hydrogen phosphate and zirconium 4-sulfophenylphosphonate having formulae Zr(HPO4)2·0.21(C33H24N4)·2.5H2O and Zr(HO3SC6H4PO3)(1.3)(C6H5PO3)(0.7)·0.35(C33H24N4)·2.5H2O were prepared and characterized by thermogravimetry, IR spectroscopy, and powder X-ray diffraction. The TPPA molecule has been selected as a model tri...

Ternary hybrid film composed of -zirconium phosphate nanosheet, 1,2-bis(dimethylchlorosilyl)ethane and polypyrrole was prepared by anodic electrodeposition. In the hybrid film, ordered -zirconium nanosheets with grafts by silylation lay down parallel to the substrate and the polypyrrole molecules were intercalated between the nanosheets. The electrochemical measurements confirmed that the hyb...