Synthesis, Characterization, and Single-Crystal X-ray Structures of d0 Refractory Metal Compounds as Precursors for the Single-Source Chemical Vapor Deposition of Metal Nitrides

The chemical vapor deposition of refractory metal nitrides requires volatile precursors and has previously been achieved using metal complexes containing a variety of imide ligands. Recently the 1,4-di-tert-butyl-1,3-diazabutadiene (DAD) adduct of bis(tert-butylimide)dichloridemolybdenum(VI) was shown to be an excellent precursor for the single-source CVD of Mo2N thin films. Leveraging the success of this work, we have prepared chromium and tungsten compounds with the same framework. Additionally, the framework has been modified slightly to allow the isolation of mono(tert-butylimide)trichloride complexes of vanadium, niobium, tantalum, and molybdenum(V) to extend the search for new vapor phase precursors. These compounds were all fully characterized using the standard methods of multi-nuclear magnetic resonance spectroscopy, combustion analysis, and single-crystal X-ray diffraction. Their thermal properties were determined using thermogravimetric analysis and differential scanning colorimetry to assess their utility as vapor phase precursors. Finally, preliminary deposition studies were carried out to investigate their potential as single-source CVD precursors.