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Results for “THALLIUM HYDRIDES”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Communication: Four-component density matrix renormalization group

We present the first implementation of the relativistic quantum chemical two- and four-component density matrix renormalization group algorithm that includes a variational description of scalar-relativistic effects and spin–orbit coupling. Numerical results based on the four-component Dirac–Coulomb Hamiltonian are presented for the standard reference molecule for correlated relativistic benchmarks: thallium hydride.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

Exploring Spin‐Orbit Effects in a [Cu 6 Tl] + Nanocluster Featuring an Uncommon Tl−H Interaction

Reaction of [CuH(PPh 3 )] 6 with 1 equiv. of Tl(OTf) results in formation of [Cu 6 TlH 6 (PPh 3 ) 6 ][OTf] ([1]OTf]), which can be isolated in good yields. Variable-temperature 1 H NMR spectroscopy, in combination with density functional theory (DFT) calculations, confirms the presence of a rare Tl−H orbital interaction. According to DFT, the 1 H chemical shift of the Tl-adjacent hydride ligands of [1] + includes 7.7 ppm of deshielding due to spin-orbit effects from the heavy Tl atom. In conclusion, this study provides valuable new insights into a rare class of metal hydrides, given that [1][OTf] is only the third isolable species reported to contain a Tl−H interaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Spin‐Orbit Effects in a Thallium Borohydride Stabilized by Coordination to Bis(diisopropylamino)Cyclopropenylidene (BAC)

The reaction of Tl(OTf) with 2 equiv of bis(diisopropylamino)cyclopropenylidene (BAC) in THF results in formation of [Tl(BAC) 2 (OTf)] (1) in moderate yields. Subsequent reaction of 1 with [K][H 2 -9-BBN] ([H 2 -9-BBN] − = dihydrido 9-boratabicyclo[3.3.1]nonane) in THF results in formation of [Tl(BAC)(μ-H 2 -9-BBN)] 2 (3), also in moderate yield. Complex 3 is the first reported thallium borohydride. We attribute its thermal stability to the strong donor ability of the BAC co-ligand. Both 1 and 3 exhibit trigonal pyramidal geometries about Tl + in the solid-state, indicative of the presence of stereochemically active lone pairs. The hydride environment in 3 is calculated to exhibit a 3.9 ppm downfield shift attributed to spin-orbit effects from the adjacent Tl center.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Developing High-Energy Laser-Driven Bremsstrahlung Radiation Sources for Imaging and Analysis of Nuclear Waste Packages - 17300

Radiographic imaging of small scale simulated nuclear waste packages (a 28 mm uranium penny encapsulated in grout) was achieved using a single pulse exposure from an x-ray source driven by a high-power laser. The high-energy laser pulse was generated at the Vulcan laser facility, which focused the photon burst onto a tantalum target foil in order to produce a bright burst of highly penetrating x-rays (with energy >500 keV) from a source size less than 0.5 mm. The sample was imaged using BAS-TR and BAS-SR image plates alongside a Thallium doped Caesium Iodide scintillator-based detector coupled to CCD chips for rapid image acquisition. The penny was resolved to sub-mm accuracy over a 30 cm{sup 2} scan area from a single shot. In addition, on a parallel beamline, neutron generation (of 10{sup 7}-10{sup 9} neutrons per steradian per pulse) was achieved, thereby demonstrating the potential application for criticality testing of waste packages. The principle concern regarding intermediate level waste (ILW) containers is the internal volumetric expansion due to the formation of corrosion products. Therefore, simulated waste samples with hydride corrosion have been formed and characterised in order to emulate this phenomenon. In addition, samples containing controlled isotopic ratios have been formed. This next generation of simulated waste samples have been produced in preparation for a second phase of analysis at the Vulcan laser facility to quantify the identification ability of radiographic imaging and characterisation accuracy of neutronics measurements. This feasibility study successfully demonstrated non-destructive radiography of encapsulated, high density, nuclear material and this paper details the next phase of technological development. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Organometallic complexes of bulky, optically active, C 3 -symmetric tris(4 S -isopropyl-5,5-dimethyl-2-oxazolinyl)phenylborate (To P *)

A bulky, optically active monoanionic scorpionate ligand, tris(4S-isopropyl-5,5-dimethyl-2-oxazolinyl)phenylborate (To P* ), is synthesized from the naturally occurring amino acid l-valine as its lithium salt, Li[To P* ] (1). That compound is readily converted to the thallium complex Tl[To P* ] (2) and to the acid derivative H[To P* ] (3). Group 7 tricarbonyl complexes To P* M(CO) 3 (M = Mn (4), Re (5)) are synthesized by the reaction of MBr(CO) 5 and Li[To P* ] and are crystallographically characterized. The ν CO bands in their infrared spectra indicate that π back-donation in the rhenium compounds is greater with To P* than with non-methylated tris(4S-isopropyl-2-oxazolinyl)phenylborate (To P ). The reaction of H[To P* ] and ZnEt 2 gives To P* ZnEt (6), while To P* ZnCl (7) is synthesized from Li[To P* ] and ZnCl 2 . The reaction of To P* ZnCl and KOtBu followed by addition of PhSiH 3 provides the zinc hydride complex To P* ZnH (8). In this study, compound 8 is the first example of a crystallographically characterized optically active zinc hydride. We tested its catalytic reactivity in the cross-dehydrocoupling of silanes and alcohols, which provided Si-chiral silanes with moderate enantioselectivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗