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We report a low-temperature colloidal synthesis of WSe2nanocrystals from tungsten hexacarbonyl and diphenyl diselenide in trioctylphosphine oxide (TOPO). We identify TOPO-substituted intermediates, W(CO)5TOPO andcis-W(CO)4(TOPO)2by infrared spectroscopy. To confirm these assignments, we synthesize aryl analogues of phosphine-oxide-substituted intermediates, W(CO)5TPPO (synthesized previously, TPPO = triphenylphosphine oxide) andcis-W(CO)4(TPPO)2andfac-W(CO)3(TPPO)3(new structures reported herein). Ligation of the tungsten carbonyl by either the alkyl or aryl phosphine oxides results in facile labilization of the remaining CO, enabling low-temperature decomposition to nucleate WSe2nanocrystals. The reactivity in phosphine oxides is contrasted with syntheses containing phosphine ligands, where substitution results in decreased CO labilization and higher temperatures are required to induce nanocrystal nucleation.
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High-pressure studies of size dependent yield strength in rhenium diboride nanocrystals
Non-hydrostatic high pressure X-ray diffraction is used to study the hardness of superhard ReB2nanocrystals. All nanocrystals show less plastic deformation under load than bulk ReB2, with the smallest nanocrystals showing the most enhancement.
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- Award ID(s):
- 2312942
- PAR ID:
- 10512060
- Publisher / Repository:
- RSC Nanoscale Horizons
- Date Published:
- Journal Name:
- Nanoscale Horizons
- Volume:
- 9
- Issue:
- 4
- ISSN:
- 2055-6756
- Page Range / eLocation ID:
- 646 to 655
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.1039/D3NH00489A
