Europium(II) and Ytterbium(II) cyclic organohydroborates: An Europium(II) complex with an agostic interaction
Europium(II) and Ytterbium(II) cyclic organohydroborates: An Europium(II) complex with an agostic interaction
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DOI：
10.1021/ic030249s
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发表时间：
2004-01-26
影响因子：
4.6
通讯作者：
Shore, SG
中科院分区：
文献类型：
--
作者：
Chen, XN;Lim, SY;Shore, SG
通过(THF)(x)LnCl(2)和K[H2BC8H14]在THF中以1:2的摩尔比进行复分解反应合成了镧系元素双((环辛烷-1,5-二基)二氢硼酸盐)配合物(THF)(4)Ln{(mu-H)(2)BC8H14}(2) (Ln = Eu, 1; Yb, 2)。制备单取代镧系元素环状有机硼氢化物(THF)(x)LnCl{(mu-H)(2)BC8H14}的尝试未成功。根据 1 的分子结构和红外光谱，Eu(II) 和 {(mu-H)(2)BC8H14} 单元中的一个 α-C-H 氢之间存在一种激动的相互作用。 2 没有观察到这种相互作用。1 和2 中的配位THF 可以在动态真空下除去，但当2 直接溶解在Et2O 或甲苯中时，溶剂配体仍然与Yb 结合。在强路易斯碱性溶剂中，例如吡啶或 CH3CN，会攻击 Yb-H-B 桥键。通过 B-11 和 H-1 NMR 光谱观察到 2 在 CD2Cl2 中分解为 9-BBN 二聚体。化合物2与2当量的氢负离子提取试剂B(C6F5)(3)反应，得到溶剂分离的离子对[Yb(THF)(6)][HB(C6F5)(3)](2)(3)。通过单晶 X 射线衍射分析对配合物 1、2 和 3 进行了表征。晶体数据：1为斜方晶系，Pna2(1)，a = 21.975(1) Angstrom，b = 9.310(1) Angstrom，c = 16.816(1) Angstrom，Z = 4； 2是三斜晶体，P1，a=9.862(1)埃，b=10.227(1)埃，c=10.476(1)埃，α=69.87(1)度，β=76.63(1)度，gamma=66.12(1)度，Z=1； 3(.)Et(2)O 是三斜晶系，P1，a = 13.708(1) 埃，b = 14.946(1) 埃，c = 17.177(1) 埃，α = 81.01(1) 度，β = 88.32(1) 度，gamma = 88.54(1) 度，Z = 2.
Lanthanide bis((cyclooctane- 1,5-diyl)dihydroborate) complexes (THF)(4)Ln{(mu-H)(2)BC8H14}(2) (Ln = Eu, 1; Yb, 2) were synthesized by a metathesis reaction between (THF)(x)LnCl(2) and K[H2BC8H14] in THF in a 1:2 molar ratio. Attempts to prepare the monosubstituted lanthanide cyclic organohydroborates (THF)(x)LnCl{(mu-H)(2)BC8H14} were unsuccessful. On the basis of the molecular structure and IR spectrum of 1, there is an agostic interaction between Eu(II) and one of the alpha-C-H hydrogens from the {(mu-H)(2)BC8H14} unit. No such interaction was observed for 2. The coordinated THF in 1 and 2 can be removed under dynamic vacuum, but the solvent ligands remain bound to Yb when 2 is directly dissolved in Et2O or toluene. In strong Lewis basic solvents, such as pyridine or CH3CN, attack of the Yb-H-B bridge bonds results. Decomposition of 2 to the 9-BBN dimer in CD2Cl2 was observed by B-11 and H-1 NMR spectroscopies. Compound 2 was reacted with 2 equiv of the hydride ion abstracting reagent B(C6F5)(3) to afford the solvent-separated ion pair [Yb(THF)(6)][HB(C6F5)(3)](2) (3). Complexes 1, 2, and 3 were characterized by single-crystal X-ray diffraction analysis. Crystal data: 1 is orthorhombic, Pna2(1), a = 21.975(1) Angstrom, b = 9.310(1) Angstrom, c = 16.816(1) Angstrom, Z = 4; 2 is triclinic, P1, a = 9.862(1) Angstrom, b = 10.227(1) Angstrom, c = 10.476(1) Angstrom, alpha = 69.87(1)degrees, beta = 76.63(1)degrees, gamma = 66.12(1)degrees, Z = 1; 3(.)Et(2)O is triclinic, P1, a = 13.708(1) Angstrom, b = 14.946(1) Angstrom, c = 17.177(1) Angstrom, alpha = 81.01(1)degrees, beta = 88.32(1)degrees, gamma = 88.54(1)degrees, Z = 2.