1H nuclear magnetic resonance (NMR), 77Se NMR, and powder X-ray diffraction (XRD) were used to monitor the thermal decomposition of diphenyl and dibenzyl diselenide precursors toward the synthesis of copper selenides. Copper was found to promote the decomposition of both precursors. The inorganic nanocrystals and organic byproducts were sensitive to the specific diaryl diselenides and the presence of oleylamine and copper. Molecular mechanistic routes are proposed. Berzelianite (Cu1.8Se), klockmannite (CuSe), umangite (Cu3Se2), and both petřı́čekite (m-CuSe2) and krutaite (p-CuSe2) were identified as products. Multistep transformations between phases were discovered through reactions with the organoselenium precursors, and organic decomposition products are proposed.

This study demonstrates that a dialkyl ditelluride reagent can produce metastable and difficult-to-achieve metal telluride phases in nanocrystal syntheses. Using didodecyl ditelluride and without the need for phosphine precursors, nanocubes...