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)(N-3)(2)](n) (1) If the reaction is carried out in pyridine (py) solution, dark red, crystalline [Ti(NMe2)(2)(N-3)(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)(N-3)(2)(bipy)] (3) and dark red crystals of [Ti(NMe2)(3)(N-3)(bipy)] (4), respectively. Crystallographic data for 2: orthorhombic, C222(1), a = 7.120(1) Angstrom, b = 15.899(3) Angstrom, c = 16.946(4) Angstrom, V = 1918.3(6) Angstrom(3), rho = 1.310 g/cm(3), Z = 4. Crystallographic data for 3: monoclinic, I2/a, a = 7.358(2) Angstrom, b = 16.808(4) Angstrom, c = 14.837(6) Angstrom, beta = 95.40(2)degrees, V = 1826.8(1) Angstrom(3), rho = 1.368 g/cm(3), Z = 4. Crystallographic data for 4: monoclinic, P2(1)/c, a = 15.682(2) Angstrom, b = 8.814(1) Angstrom, c = 15.128(1) Angstrom, beta = 108.39(1)degrees, V = 1984.2(4) Angstrom(3), rho = 1.267 g/cm(3), 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 degrees C. The TiN films deposited from precursor 2 are superior to those deposited from 1.