Monomeric Titanium(IV) Azides as a New Route to Titanium Nitride

The reaction of Ti(NMe2)4 with 2 equiv of Me3SiN3 in toluene solution affords a dark red polymeric material of composition [Ti(NMe2)2(N3)2]n (1). If the reaction is carried out in pyridine (py) solution, dark red, crystalline [Ti(NMe2)2(N3)2(py)2] (2) is formed. Analogous reactions of Ti(NMe2)4 with 2 or 1 equiv of Me3SiN3 in the presence of 1 equiv of bipyridyl (bipy) in toluene solution afford brown crystals of [Ti(NMe2)2(N3)2(bipy)] (3) and dark red crystals of [Ti(NMe2)3(N3)(bipy)] (4), respectively. Crystallographic data for 2: orthorhombic, C2221, a = 7.120(1) Å, b = 15.899(3) Å, c = 16.946(4) Å, V = 1918.3(6) Å3, ρ = 1.310 g/cm3, Z = 4. Crystallographic data for 3: monoclinic, I2/a, a = 7.358(2) Å, b = 16.808(4) Å, c = 14.837(6) Å, β = 95.40(2)°, V = 1826.8(1) Å3, ρ = 1.368 g/cm3, Z = 4. Crystallographic data for 4: monoclinic, P21/c, a = 15.682(2) Å, b = 8.814(1) Å, c = 15.128(1) Å, β = 108.39(1)°, V = 1984.2(4) Å3, ρ = 1.267 g/cm3, Z = 4. Compounds 1 and 2 deposit thin films of titanium nitride (TiN) on silica and/or nickel substrates in the temperature range 300−400 °C. The TiN films deposited from precursor 2 are superior to those deposited from 1.