A New Approach to the Synthesis of Nanocrystalline Cobalt Boride in the Course of the Thermal Decomposition of Cobalt Complexes [Co(DMF)] with Boron Cluster Anions.

In the course of the study, nanocrystalline cobalt monoboride was prepared by thermal decomposition of precursors [Co(DMF)][An], where [An] = [BH] (), [-BH] () or [BCl] () in an argon atmosphere. Three new salt-like compounds - were prepared when Co(NO) was allowed to react with (EtNH)[An]. Compound is new; the structures of compounds and have been previously reported. Samples - were annealed at 900 °C in argon to form samples -, which were characterized by single crystal XRD for and powder XRD for . Powder XRD on the products showed the formation of BN and CoB for in a 1:1 ratio; gave a higher CoB:BN ratio but an overall decreased crystallinity. For , only CoB was found. IR spectra of samples - as well as X-ray spectral fluorescence analysis for 3a confirmed these results. The nanoparticular character of the decomposition products - was shown using TEM; quite small particle sizes of about 10-15 nm and a quite normal size distribution were found for and a, while the decomposition of gave large particles with 200-350 nm and a broad distribution.