95045-72-0Relevant academic research and scientific papers
Synthesis, structure, spectroscopic properties, and electrochemical behavior of group 4 metal derivatives containing bulky aryloxide ligands
Latesky, Stanley L.,Keddington, Judy,McMullen, Anne K.,Rothwell, Ian P.,Huffman, John C.
, p. 995 - 1001 (2008/10/08)
Use of the sterically demanding ligand 2,6-di-tert-butylphenoxide (OAr′) allows the isolation of a number of mononuclear, mixed halo-aryloxides of titanium, zirconium, and hafnium. The products can be grouped into three types. The dihalides Ti(OAr′)2X2 (X = Cl, Br) are deep red solids extremely soluble in all hydrocarbon solvents. Molecular weight measurements indicate a monomeric structure in benzene. The monohalides M(OAr′)3Cl (M = Ti, Zr, Hf) and Ti(OAr′)3X (X = Br, I) are monomeric in solution, and 1H NMR data show that restricted rotation about the M-O-Ar′ bonds occur, leading to nonequivalent tert-butyl groups at low temperature. X-ray diffraction studies on HfCl(OAr′)3 and TiI(OAr′)3 show the compounds to be isostructural with an extremely congested metal coordination sphere. The paramagnetic, blue complex Ti(OAr′)3 can be obtained in good yield from TiCl3(NMe3)2 and excess LiOAr′ in benzene. Crystal data for HfCl(OAr′)3 at -165°C: a = 17.521 (5) A?, b = 11.155 (2) A?, c = 10.686 (2) A?, α = 104.71 (1)°, β= 99.51 (1)°, γ = 83.82 (1)°, Z = 2, and dcalcd = 1.387 g cm-3 in space group P1. Crystal data for TiI(OAr′)3 at -164°C: a = 17.327 (8) A?, b = 11.088 (5) A?, c = 10.928 (4) A?, α = 106.09 (2)°, β = 100.29 (2)°, γ = 82.54 (2)°, Z = 2, and dcalcd, = 1.328 g cm-3 in space group P1. An investigation of the electrochemistry of these compounds shows that the dihalides Ti(OAr′)2X2 (X = Cl, Br) undergo reversible one-electron reductions to the corresponding monoanions while for the more sterically crowded Ti(OAr′)3X (X = Cl, Br, I) reduction products are halide dependent.
