156822-13-8Relevant articles and documents
Synthesis, properties, and X-ray structures of the lanthanide η6-arene-bridged aryloxide dimers Ln2(O-2,6-i-Pr2C6H3)6 and their lewis base adducts Ln(O-2,6-i-Pr2C6H3)3(THF)2 (Ln = Pr, Nd, Sm, Gd, Er, Yb, Lu)
Barnhart, David M.,Clark, David L.,Gordon, John C.,Huffman, John C.,Vincent, Rebecca L.,Watkin, John G.,Zwick, Bill D.
, p. 3487 - 3497 (2008/10/08)
Reaction of 3 equiv of 2,6-diisopropylphenol with Ln[N(SiMe3)2]3 (Ln = Nd, Sm, Er) in refluxing toluene and subsequent crystallization yield pale blue (Nd), deep yellow (Sm), or light pink (Er) crystals of the tris(aryloxide) complexes Ln2(O-2,6-i-Pr2C6H3)6 (Ln = Nd (1), Sm (2), Er (3)) in good yield. X-ray crystallographic studies of 1 and 2 reveal centrosymmetric, dimeric units bridged by η6-π-arene interactions of a unique aryloxide ligand. Ln-O bond lengths average 2.122(9) (1, Nd) and 2.101(6) A? (2, Sm) for terminal ligands and 2.211(8) (1) and 2.198(5) A? (2) for bridging aryloxide ligands. η6-Arene bridges hold the dimeric units together with an average Ln-C distance of 3.035 A? for 1 and 2.986 and 3.016 A? for the two independent molecules in the asymmetric unit of 2. Compounds 1-3 react with THF in toluene solution to give the THF bisadducts Ln(O-2,6-i-Pr2C6H3)3(THF) 2 (Ln = Nd (4), Sm (5), Er (6)) in essentially quantitative yield. In a related fashion, Lu(O-2,6-i-Pr2C6H3)3(THF) 2 (7) was prepared following the reaction of Lu[N(SiMe3)2]3 with 3 equiv of diisopropylphenol in the presence of THF. The anhydrous trichlorides of Sm, Pr, Gd, and Yb react with 3 equiv of potassium 2,6-diisopropylphenoxide in THF solution to give the 5-coordinate THF bisadducts Ln(O-2,6-i-Pr2C6H3)3(THF) 2 (Ln = Sm (5), Pr (8), Gd (9), Yb (10)). X-ray crystal structures have been obtained for Ln(O-2,6-i-Pr2C6H3)3(THF) 2 (Ln = Er (6), Lu (7), Pr (8), Gd (9)). The four compounds are isostructural, and the molecular structure consists of a distorted trigonal bipyramidal lanthanide metal center with two axial THF and three equatorial aryloxide ligands. Ln-O distances for the aryloxide ligands average 2.078 (6, Er), 2.044 (7, Lu), 2.172 (8, Pr), and 2.130 (9, Gd) while Ln-O distances for the THF ligands average 2.346 (6), 2.296 (7), 2.482 (8), and 2.394 A? (9). Solution 1H and 13C NMR data, together with solution IR data, strongly support the proposal that the π-arene-bridged dimeric structures of 1-3 are maintained in both benzene and toluene solutions at room temperature. Crystal data for 1 (at -162°C): monoclinic space group P21/a, a = 9.536(2) A?, b = 21.219(6) A?, c = 17.162(5) A?, β = 104.43(1)°, V = 3363.0 A?3, Z = 2, dcalc = 1.335 g cm-3, R(F) = 0.0518, Rw(F) = 0.0522. Crystal data for 2 (at -70°C): monoclinic space group P21/c, a = 9.555(2) A?, b = 21.301(2) A?, c = 33.220(4) A?, β = 91.50(3)°, V = 6759 A?3, Z = 2 (2 molecules per asymmetric unit), dcalc = 1.341 g cm-3, R(F) = 0.0447, Rw(F) = 0.0640. Crystal data for 6 (at -170°C): monoclinic space group P21, a = 9.693(1) A?, b = 19.141(3) A?, c = 12.083(1) A?, β = 109.48(1)°, V = 2113.50 A?3, dcalc = 1.325 g cm-3, Z = 2, R(F) = 0.047, Rw(F) = 0.063. Crystal data for 7 (at-70°C): monoclinic space group P21, a = 9.632(1) A?, b = 19.269(2) A?, c = 12.164(1) A?, β = 109.52(1)°, V = 2127.9 A?3, dcalc = 1.328 g cm-3, Z = 2, R(F) = 0.021, Rw(F) = 0.031. Crystal data for 8 (at -70°C): monoclinic space group P21, a = 9.857(2) A?, b = 19.408(4) A?, c = 12.085(3) A?, β = 109.81(2)°, V = 2175.1 A?3, dcalc = 1.247g cm-3, Z = 2, R(F) = 0.045, RW(F) = 0.061. Crystal data for 9 (at -70°C): monoclinic space group P21, a = 9.755(1) A?, b = 19.377(2) A?, c = 12.184(1) A?, β = 109.65(1)°, V = 2168.1 A?3, dcalc = 1.276 g cm-3, Z = 2, R(F) = 0.054, Rw(F) = 0.073.
