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.