Titanium Imido Complexes with Tetradentate Schiff Base Ligands

New mono- and binuclear titanium imido complexes supported by tetradentate, dianionic N2O2-donor Schiff base
ligands were prepared in good yield from the readily available [Ti(NBut)Cl2(py)3] (1a). Thus treatment of 1a
with Na2[substituted-salen] gave monomeric [Ti(NBut)(substituted-salen)] where substituted-salen = Et2salen (2)
or But4salen (4). In contrast, the binuclear complex [Ti(NBut){μ-(MeO)2salen}]2 (5) was obtained from 1a and
Na2[(MeO)2salen]. The less sterically crowded compounds 2 and 5 undergo tert-butyl imide/arylamine exchange
reactions to form [Ti(N-2,6-C6H3Me2)(Et2salen)] (3) and [Ti(N-2,6-C6H3Me2){μ-(MeO)2salen}]2 (6), respectively,
whereas 4 does not exhibit this kind of reactivity. The compound 3 can also be obtained directly from Na2[Et2salen]
and [Ti(N-2,6-C6H3Me2)Cl2(py)3] (1b). Crystal data for 3:  triclinic, P1̄, a = 12.216(4) Å, b = 12.312(11) Å, c
= 17.246(2) Å, α = 90.352(12)°, β = 102.59(2)°, γ = 104.96(2)°, V = 2440.3(8) Å3, Z = 4, R = 0.051, Rw =
0.066 for 7011 data with I > 2σ(I). Crystal data for 5·CH2Cl2:  orthorhombic, Pbca, a = 14.747(4) Å, b =
17.042(4) Å, c = 20.545(3) Å, V = 5163.5(13) Å3, Z = 4, R1 = 0.096, wR2 = 0.086 for 3765 data with I > 2σ(I).
Crystal data for 6:  monoclinic, C2/c, a = 17.902(5) Å, b = 12.411(4) Å, c = 21.068(5) Å, β = 90.27(2)°, V =
4681(2) Å3, Z = 4, R = 0.034, Rw = 0.039 for 3633 data with I > 2σ(I).