110527-87-2Relevant academic research and scientific papers
Synthesis and crystal and molecular structures of M(OAr′)2(CH2-py-6Me)2 (M = Hf, Th; OAr′ = 2,6-di-tert-butylphenoxide; CH2-py-6Me = 2-(6-methylpyridyl)methyl), complexes containing two C,N-chelating pyridyl-methyl ligands
Beshouri, Sharon M.,Fanwick, Phillip E.,Rothwell, Ian P.,Huffman, John C.
, p. 2498 - 2502 (2008/10/08)
The reaction of the tetrachlorides MCl4 (M = Hf, Th) with excess of LiCH2-py-6Me (LiCH2-py-6Me = (2-(6-methylpyridyl)methyl)lithium) leads to the sparingly soluble dialkyls MCl2(CH2-py-6Me)2 (M = Hf, Th). Further treatment of these materials with LiOAr′ (>2 equiv; OAr′ = 2,6-di-tert-butylphenoxide) leads to the pale yellow, crystalline compounds M(OAr′)2(CH2-py-6Me)2 (M = Hf, Th) which are soluble in hydrocarbon solvents and are more amenable to study. Structural studies show both the hafnium and thorium compounds to be isomorphous and isostructural, the metal being found to be six-coordinate with both pyridyl-methyl ligands C,N-chelating. Some distortions of the coordination environment are evident, presumably due to the formation of two strained, four-membered rings. Although the M-N(py) distances do not appear to be elongated, solution studies indicate that dissociation of pyridine groups is facile. However, 13C NMR data are supportive of the idea that the ligands remain predominantly, C,N-bound in solution. Hf(OAr′)2(CH2-py-6Me)2 crystallizes in space group I2/a with a = 16.980 (4) ?, b = 10.438 (1) ? c = 21.865 (5) ?, β = 106.77 (1)°, Z = 4, and dcalcd = 1.435 g cm-3 at -157°C. Th(OAr′)2(CH2-py-6Me)2 also crystallizes in space group I2/a with a = 16.826 (5) ?, b = 10.679 (1) ?, c = 22.491 (5) ?, β = 106.04 (2)° Z = 4, and dcalcd = 1.462 g cm-3 at 22°C.
