DISSOLUTION OF LANTHANIDE AND ACTINIDE METALS USING IODINE AND 2-PROPANOL - SYNTHESIS AND X-RAY CRYSTAL-STRUCTURES OF LNI(3)(HO-I-PR)(4) (LN=LA, CE) AND TH2I4(O-I-PR)(4)(HO-I-PR)(2)

Reaction of lanthanum, cerium, or neodymium metals with 3/2 equiv of iodine in 2-propanol leads to formation of the alcohol adducts LnI(3)(HO-i-Pr)(4) (Ln = La (1), Ce (2), Nd (3)) in good yield. Reaction of thorium metal turnings with 2 equiv of iodine in 2-propanol produces the dimeric halide-alkoxide complex Th2I4(O-i-Pr)(4)(HO-i-Pr)(2) (4). The molecular structures of 1, 2, and 4 have been determined by means of single-crystal X-ray diffraction studies. 1 and 2 are found to be isostructural, and consist of seven-coordinate metal centers best described as capped trigonal prisms in which an iodide ligand caps a rectangular face defined by the four 2-propanol oxygen atoms. Ln-I bond lengths lie in the ranges 3.180(1)-3.224(1) for 1 and 3.157(1)-3.191(1) Angstrom for 2, while Ln-O distances to the 2-propanol ligands average 2.509(7) and 2.488(5) Angstrom for 1 and 2, respectively. 4 exhibits an edge-shared bioctahedral geometry with 2-propoxide ligands occupying bridging positions. Bridging Th-O distances in 4 are 2.327(6) and 2.399(6) Angstrom, while the Th-O distance to the terminal 2-propoxide ligand is extremely short at 2.056(7) Angstrom. The Th-O bond length to the 2-propanol ligand is characteristically long at 2.437(6) Angstrom, while Th-I distances are 3.094(1) and 3.104(1) Angstrom. Crystal data for 1 (at -70 degrees C): orthorhombic space group Pbca, a = 17.240(3) Angstrom, b = 13.944(2) Angstrom, c = 19.178(2) Angstrom, V = 4610.3 Angstrom(3), d(calc) = 2.190 g cm(-3), Z = 8, R = 0.0439, R(w) = 0.0739. Crystal data for 2 (at -70 degrees C): orthorhombic space group Pbca, a = 17.199(3) Angstrom, b = 13.884(3) Angstrom, c = 19.153(4) Angstrom, V = 4573.5 Angstrom(3), d(calc) = 2.211 g cm(-3), Z = 8, R = 0.0352, R(w) = 0.0619. Crystal data for 4 (at -48 degrees C): triclinic space group P $($) over bar$$ 1, a = 9.658(2) Angstrom, b = 9.754(2) Angstrom, c = 11.563(2) Angstrom, alpha = 109.41(3)degrees, beta = 95.18(3)degrees, gamma = 117.33(3)degrees, V = 873.5 Angstrom(3), d(calc) = 2.521 g cm(-3), Z = 1, R = 0.0319, R(w) = 0.0506.