Treatment of the mono(η2-iminoacyl) compound Ti(OAr-2,6-Pri2)2(η2-ButNCCH2Ph)(CH2Ph) with 1 equiv of pyridine ligands L = pyridine (py) 4-phenylpyridine (py-4-Ph) 4-ethylpyridine (py-4-Et) 4-pyrrolidinopyridine (py-4-pd) leads to the quantitative formation of the η2-imine compounds Ti(OAr-2,6Pri2)2[η2-ButNC(CH2Ph)2](L) (1a, L = py; 1b, L = py-4-Ph; 1c, L = py-4-Et; 1d, L = py-4-pd). The η2-CN binding of the imine ligands in compounds 1 was confirmed both by spectroscopic data and by a single-crystal X-ray diffraction analysis of 1b and 1c. In both compounds, the presence of an azametallacyclopropane (metallaaziridine) ring was shown with distances Ti-N = 1.846 (4), 1.855 (2) Å, Ti-C = 2.158 (5), 2.150 (2) Å, and N‒C = 1.421 (7), 1.410 (3) Å for 1b and 1c, respectively. These parameters are interpreted in terms of a Ti(IV) metal center bound to a dianionic [RʹN-CR2]2- fragment and not as a neutral imine ligand loosely π-bound to Ti(II). Consistent with this is the treatment of 1 with H2O to generate the amine ButNHCH(CH2Ph)2 along with titanium oxo species. Treatment of 1 with the α-diimine PhN═C(Me)C(Me)═NPh leads to the formation of the enediamide compound Ti(OAr-2,6-Pri2)2[PhNC-(Me)=C(Me)NPh] (2). The η2-bound imine in 1 will also undergo reaction with azobenzene to generate free ΒutN═C(ΟΗ2Ρ1h)2 and the η2-azobenzene complex Ti(OAr-2,6Pri2)2(η2-PhNNPh)(py)2 (3). A single-crystal X-ray diffraction analysis of 2 showed the azobenzene strongly bound with Ti-N = 1.95 Å (average) and with an N-N single-bond distance of 1.42 Å (average). Crystal data for TiO2N2C54H66 (1b) at -155 °C: a = 12.970 (4), b = 12.927 (3), c = 28.140 (4) Å; β = 97.38 (2)°; Z = 4; dcalcd = 1.168 g cm-3 in space group P21/c. Crystal data for TiO2N2C50H67 (1c) at -100 °C: a = 10.748 (2), b = 17.424 (3), c = 24.673 (2) ~; β = 98.442 (9)°; Z = 4; dcalcd = 1.128 g cm-3 in space group P21/c. Crystal data for TiO2N4C46H54 (3) at -162 °C: a = 38.770 (6), b = 17.858 (30), c = 9.892 (3) Å; β = 97.18 (2)°; Z = 6; dcalcd= 1-089 g cm-3 in space group C2. © 1990, American Chemical Society. All rights reserved.
