Synthesis and Molecular Structure of Iron(III) Diaryl-Dithiocarbamate Complexes, [Fe(S2CNAr2)3], and a Preliminary Study Exploring Their Potential as Single-Source Precursors for Nanoscale Iron Sulfides

Diaryldithiocarbamate complexes, [Fe(S2CNAr2)3], have been prepared and their structure, reactivity, and thermal degradation to afford iron sulfide nanomaterials have been investigated. The addition of three equivalents of LiS2CNAr2 to FeCl2·4H2O in water-air affords dark red [Fe(S2CNAr2)3] in high yields. All show magnetic measurements consistent with a predominantly high-spin electronic arrangement at room temperature. The molecular structure of [Fe{S2C(N-p-MeOC6H4)2}3] reveals the expected distorted octahedral geometry, but Fe-S distances are more consistent with a low-spin electronic configuration, likely a result of the low temperature (120 K) of the data collection. The thermal stability of [Fe{S2C(N-p-MeC6H4)2}3] has been investigated. TGA shows that it begins to decompose at a significantly lower temperature (ca. 160 °C) than previously observed for [Fe(S2CNEt2)3], and this is further lowered (to ca. 100 °C) in oleylamine. The decomposition of [Fe{S2C(N-p-MeC6H4)2}3] in oleylamine, via either a heat-up or hot injection process, affords nanoparticles of Fe3S4 (greigite), while in contrast, dry heating at 450 °C affords FeS (troilite) as large agglomerates.