New octahedral Ta(V) hydrazido-substituted compounds for atomic layer deposition: Syntheses, X-ray diffraction structures of TaCl(NMe2)3[N(TMS)NMe2] and Ta(NMe2)4[N(TMS)NMe2], and fluxional behavior of the amido and hydrazido ligands in solution

The synthesis and structural characterization of new tantalum(V) compounds containing a single hydrazido(I) ligand are reported. Hydrazinolysis of TaCl(NMe2)4 using trimethylsilyl(dimethyl)hydrazine affords the compound TaCl(NMe2)3[N(TMS)NMe2] in essentially quantitative yield. Metathetical replacement of the chloride ligand in TaCl(NMe2)3[N(TMS)NMe2] by LiNMe2 gives the all-nitrogen coordinated compound Ta(NMe2)4[N(TMS)NMe2]. VT 1H NMR studies support the existence of low-energy pathways involving rotation about the Ta–N bonds of the ancillary amido and hydrazido ligands in both hydrazido-substituted compounds. X-ray crystallographic analyses confirm the octahedral disposition about the tantalum metal in TaCl(NMe2)3[N(TMS)NMe2] and Ta(NMe2)4[N(TMS)NMe2] and the presence of an η2-hydrazido(I) ligand. Preliminary data using Ta(NMe2)4[N(TMS)NMe2] as an ALD precursor for the preparation of tantalum nitride and tantalum oxide thin films are presented.

The new hydrazido-substituted compounds TaCl(NMe2)3[N(TMS)NMe2] and Ta(NMe2)4[N(TMS)NMe2] have been synthesized and their structures established by X-ray crystallography. The latter product represents the first structurally characterized octahedral tantalum(V) complex containing a single hydrazido(I) ligand in an all-nitrogen coordinated environment about the metal center. The fluxional properties of the amido and hydrazido ligands in these new compounds have been established by VT 1H NMR spectroscopy. Preliminary data using Ta(NMe2)4[N(TMS)NMe2] as an ALD precursor for the preparation of tantalum nitride and tantalum oxide thin films are presented.Figure optionsDownload as PowerPoint slide