Dibenzyl Diselenide as a Monitorable, Atom-Efficient Se Source for the Synthesis of Cu₃PSe₄ Nanoparticles

Complex ternary composition nanoparticles (NPs) are highly desired for a range of potential applications, but their syntheses often rely on empirical syntheses rather than designed, ideally mechanism-based, syntheses. Here, we focus on colloidal Cu3PSe4 nanoparticles as a model system, one we have previously prepared from Cu3–xP and solid Se. However, in that prior system quantitatively following the conversion of solid Se into the Cu3PSe4 product is problematic, in turn meaning that the balanced reaction stoichiometry and, hence, mechanistic insights remain elusive. Herein, we show that dibenzyl diselenide (Bn2Se2) has considerable utility in the synthesis of Cu3PSe4 NPs. Using Cu3–xP plus 2 equiv of Bn2Se2 yields Cu3PSe4 as the main NP product. The benzyl moiety (PhCH2−), coupled with NMR and gas chromatography–mass spectrometry (GC-MS) handles, establishes that benzyl loss and toluene (PhCH3) gain are a monitorable proxy for net Se02 delivery when the facile, net two H• donor 9,10-dihydroanthracene is added. The experiments performed and the results obtained help to further lay the groundwork for the expanded use of Bn2Se2 as a Se02 delivery reagent for the syntheses of Se-containing materials. More broadly, the results herein support the use of molecular precursors, chosen based on previously established chemistry, that allow trackable, quantifiable reaction products in NP and related material syntheses.