AUTHOR=Geisenhoff Jessica Q. , Yin Hang , Oget Natacha , Chang Haeun , Chen Linfeng , Schimpf Alina M. 

TITLE=Controlled CO labilization of tungsten carbonyl precursors for the low-temperature synthesis of tungsten diselenide nanocrystals

JOURNAL=Frontiers in Nanotechnology

VOLUME=4

YEAR=2022

URL=https://www.frontiersin.org/journals/nanotechnology/articles/10.3389/fnano.2022.1026635

DOI=10.3389/fnano.2022.1026635

ISSN=2673-3013

ABSTRACT=<p>We report a low-temperature colloidal synthesis of WSe<sub>2</sub> nanocrystals from tungsten hexacarbonyl and diphenyl diselenide in trioctylphosphine oxide (TOPO). We identify TOPO-substituted intermediates, W(CO)<sub>5</sub>TOPO and <italic>cis-</italic>W(CO)<sub>4</sub>(TOPO)<sub>2</sub> by infrared spectroscopy. To confirm these assignments, we synthesize aryl analogues of phosphine-oxide-substituted intermediates, W(CO)<sub>5</sub>TPPO (synthesized previously, TPPO = triphenylphosphine oxide) and <italic>cis-</italic>W(CO)<sub>4</sub>(TPPO)<sub>2</sub> and <italic>fac-</italic>W(CO)<sub>3</sub>(TPPO)<sub>3</sub> (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 WSe<sub>2</sub> nanocrystals. 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.</p>