Dithiocarbamate Precursors for Rare-Earth Sulfides

We have synthesized a series of lanthanide dithiocarbamate precursors for the synthesis of lanthanide sulfide materials and nanoparticles. Three dithiocarbamate complexes with europium, Eu(S2CNRR‘)3L, where L = 1,10-phenanthroline, and R = methyl, R‘ = ethyl (1), R = R‘ = nPropyl (2), and R = R‘ = iButyl (3), as well as the lanthanide complexes, Ln(S2CNR2)3 L, where R = ethyl, L = 1, 10-phenanthroline, and Ln = Nd (4), Sm (5), Gd (6), Ho (7), and Er (8), were synthesized and characterized by single-crystal X-ray diffraction, infrared, NMR, and UV−visible spectroscopy. We have used thermal analysis coupled with GC−MS and X-ray powder diffraction to determine the mechanism of decomposition. With R = Et, smaller Ln ions give lower precursor decomposition temperatures, consistent with the higher lattice energies of the product Ln sulfides. Because they are monomeric, and water- and air-stable, these compounds should be ideal precursors for forming LnS as nanoparticles and bulk materials.