Transition Metal Polysulfide Complexes as Single-Source Precursors for Metal Sulfide Nanocrystals

The metal polysulfide complexes [M(N-MeIm)(6)]S-8 (M = Fe, Ni) and ZnS6(N-MeIm)(2) (N-MeIm = N-methylimidazole) were synthesized and used as single-source precursors for the synthesis of metal sulfide nanocrystals. Rapid injection of [Ni(N-MeIm)(6)]S-8 into oleylamine at 300 degrees C, followed by immediate cooling, led to the formation of spherical, monodisperse 6 nm NiS2 nanocrystals. Whereas reaction of [Ni(N-MeIm)(6)]S-8 by gradual heating in oleylamine to 300 degrees C led to the formation of irregularly shaped 45 nm alpha-Ni1-xS nanocrystals. Rapid injection of [Fe(N-MeIm)(6)]S-8 into oleylamine at 300 degrees C, followed by immediate cooling, led to the information of 16 nm Fe3S4 nanocrystals. Whereas reaction of [Fe(N-MeIm)(6)]S-8 in oleylamine at 300 degrees C for 4 h led to the formation of faceted, submicrometer Fe1-xS crystallites. Reaction of ZnS6(N-MeIm)(2) in oleylamine at 300 degrees C for 30 min led to the formation of monodisperse 11 x 5 nm ZnS nanorods. Metal polysulfide complexes were shown to be viable single-source precursors for a range of transition metal sulfide nanocrystals, with all samples demonstrating a high degree of crystallinity and excellent phase-purity.