Synthesis and characterization of 2-hydroxy-pyridine modified Group 4 alkoxides
Journal of Coordination Chemistry
The reaction of Group 4 metal alkoxides ([M(OR)4]) with the potentially bidentate ligand, 2-hydroxy-pyridine (2-HO-(NC5H4) or H-PyO), led to the isolation of a family of compounds. The products isolated from the reaction of [M(OR)4] [where M = Ti, Zr, or Hf; OR = OPri (OCH(CH3)2), OBut (OC(CH3)3), or ONep (OCH2C(CH3)3] under a variety of stoichiometries with H-PyO were identified by single crystal X-ray diffraction as [(OPri)2(PyO-κ2(O,N))Ti(μ-OPri)]2 (1), [(ONep)2Ti(μ(O)-PyO-κ2(O,N))2(μ-ONep)Ti(ONep)3] (2), [(ONep)2Ti(μ(O)-PyO-κ2(O,N))(η1(N),μ(O)-PyO)(μ-O)Ti(ONep)2]2 (2a), [H][(PyO-κ2(O,N))(η1(O)-PyO)Ti(ONep)3] (3), [(OR)2Zr(μ(O)-PyO-κ2(O,N))2(μ-OR)Zr(OR)3] (OR = OBut (4), ONep (5)), [(OR)2Zr(μ(O,N)-PyO-κ2(O,N))2(μ(O,N)-PyO)Zr(OR)3] (OR = OBut (6), ONep (7)), [[(OBut)2Zr(μ(O)-PyO-(κ2(N,O))(μ(O,N)-PyO)2Zr(OBut)](μ3-O)]2 (6a), [[(ONep)(PyO-κ2(N,O))Zr(μ(O,N)-PyO-κ2(N,O))2(μ(O)-PyO-κ2(N,O))Zr(ONep)](μ3-O)]2 (7a), [(OBut)(PyO-κ2(O,N))Zr(μ(O)-PyO-κ2(O,N))2((μ(O,N)-PyO)Zr(OBut)3] (8), [(OBut)2Hf(μ(O)-PyO-κ2(N,O))2(μ-OBut)Hf(OBut)3] (9), [(OR)2 M(μ(O)-PyO-κ2(N,O))2(μ(O,N)-PyO)M(OR)3] (OR = OBut (10), ONep (11)), and [(ONep)3Hf(μ-ONep)(η1(N),μ(O)-PyO)]2Hf(ONep)2 (12)·tol. The structural diversity of the binding modes of the PyO led to a number of novel structure types in comparison to other pyridine alkoxy derivatives. The majority of compounds adopt a dinuclear arrangement (1, 2, 4–11) but oxo-based tetra- (2a and 7a), tri- (12), and monomers (3) were observed as well. Compounds 1–12 were further characterized using a variety of analytical techniques including Fourier Transform Infrared Spectroscopy, elemental analysis, and multinuclear NMR spectroscopy.