Titanium(IV)azido and imido complexes as potential precursors to titanium nitride

Abstract

Synthetic and structural studies have been performed for two imido complexes of titanium(IV). The reaction between [{Ti(NBu^t)Cl₂(NH₂Bu^t)₂}₃] and 6 equivalents of Me₃SiN₃ at room temperature in the presence of pyridine resulted in the substitution of only one chloride per titanium atom and formation of the dimeric complex [{Ti(NBu^t)Cl(N₃)(py)₂}₂] (py = pyridine). An alternative approach to such complexes, which involved the reaction between [Ti(NMe₂)₂(N₃)₂(py)₂] and 1 equivalent of CyNH₂ at room temperature, resulted in the dimeric bis(azide) complex [{Ti(NCy)(N₃)₂(py)₂}₂] (Cy = cyclohexyl). The two new complexes have been characterised by X-ray crystallography; the solid state of each comprises dimeric units in which the two titanium atoms are bridged by a pair of azide ligands. A gas-phase pyrolysis study has been conducted on [Ti(NMe₂)₂(N₃)₂(py)₂] and preliminary CVD experiments on the two new complexes revealed that they are not effective titanium nitride precursors.