- Facile solution routes to hydrocarbon-soluble Lewis base adducts of thorium tetrahalides. Synthesis, characterization, and X-ray structure of ThBr4(THF)4
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The direct combination of thorium metal turnings with 2 equiv of elemental bromine or iodine in THF solution at 0°C provides white crystalline ThX4(THF)4 (X = Br, 1; X = I, 2; THF = tetrahydrofuran), in 70-80% isolated yield. These new compounds are soluble in hydrocarbon solvents and react readily with oxygen- and nitrogen-donor ligands in toluene solution to give ThBr4py4 (3), ThI4py4 (4), ThBr4(NCMe)4, (5), and ThBr4(DME)2 (6) in high yield (py = pyridine, DME = 1,2-dimethoxyethane). Compounds 1-6 have been characterized by elemental and thermogravimetric analysis, 1H NMR, infrared, and diffuse-reflectance spectroscopy, and, for 1, a single-crystal X-ray structure determination. The X-ray diffraction study of 1 revealed a slightly distorted dodecahedral coordination geometry about the central thorium atom with two interpenetrating tetrahedra of bromide and THF ligands. Oxygen atoms of the THF ligands occupy A vertices (Th-O = 2.549 (17) A?, average) and bromide ions occupy B vertices (Th-Br = 2.859 (3) A?, average) of an irregular dodecahedron. 1 is an excellent synthetic precursor to thorium coordination and organometallic complexes and can be prepared on a 100-150-g scale in a single day. Crystal data for 1 (at -40°C): Rhombohedral space group R3, with a = 26.317 (4) A?, c = 18.340 (4) A?, V = 11000 A?3, dcalc = 2.299 g cm-3, and Z = 18.
- Clark, David L.,Frankcom, Tracey M.,Miller, Mary M.,Watkin, John G.
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p. 1628 - 1633
(2008/10/08)
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