Fabrication, thermal analysis, and heavy ion irradiation resistance of epoxy matrix nanocomposites loaded with silane-functionalized ceria nanoparticles.

This paper describes a detailed understanding of how nanofillers function as radiation barriers within the polymer matrix, and how their effectiveness is impacted by factors such as composition, size, loading, surface chemistry, and dispersion. We designed a comprehensive investigation of heavy ion irradiation resistance in epoxy matrix composites loaded with surface-modified ceria nanofillers, utilizing tandem computational and experimental methods to elucidate radiolytic damage processes and relate them to chemical and structural changes observed through thermal analysis, vibrational spectroscopy, and electron microscopy. A detailed mechanistic examination supported by FTIR spectroscopy data identified the bisphenol A moiety as a primary target for degradation reactions.

Monomeric thorium chalcogenolates with bipyridine and terpyridine ligands.

Thorium chalcogenolates Th(ER)4 react with 2,2'-bipyridine (bipy) to form complexes with the stoichiometry (bipy)2Th(ER)4 (E = S, Se; R = Ph, C6F5). All four compounds have been isolated and characterized by spectroscopic methods and low-temperature single crystal X-ray diffraction. Two of the products, (bipy)2Th(SC6F5)4 and (bipy)2Th(SeC6F5)4, crystallize with lattice solvent, (bipy)2Th(SPh)4 crystallizes with no lattice solvent, and the selenolate (bipy)2Th(SePh)4 crystallizes in two phases, with and without lattice solvent.

Thorium Cubanes-Synthesis, Solid-State and Solution Structures, Thermolysis, and Chalcogen Exchange Reactions.

Thorium cubanes (py)Th(μ-E')(μ-EPh)(η-EPh) (E, E' = S, Se) were prepared from ligand-based redox reactions of elemental E' with Th(EPh). Products with all four possible E/E' combinations (E,E' = S,S; Se,Se; S,Se; Se,S) were isolated and structurally characterized, ligand exchange reactions were explored, and the heterochalcogen compounds (py)Th(μ-S)(μ-SePh)(η-SePh) and (py)Th(μ-Se)(μ-SPh)(η-SPh) were heated to deliver solid solutions of ThS Se. NMR spectroscopy indicated that the structure of (py)Th(μ-Se)(μ-SePh)(η-SePh) is static in pyridine solution, with no exchange between bridging and terminal PhE ligands on the NMR time scale.

Iridium-catalyzed, substrate-directed C-H borylation reactions of benzylic amines.

The iridium-catalyzed arene C-H borylation reaction of benzylic amines has been developed, which inverts the typical steric-controlled product distribution to provide ortho-substituted boronate esters. Picolylamine was found to be an ideal ligand to replace 4,4'-di-tert-butylbipyridine to induce the directing effect. Preliminary experiments are consistent with a mechanism involving dissociation of one amine of the hemilabile diamine ligand.