Reversible Coordination of Boron-, Aluminum-, Zinc-, Magnesium-, and Calcium-Hydrogen Bonds to Bent {CuL2} Fragments: Heavy σ Complexes of the Lightest Coinage Metal
Reversible Coordination of Boron-, Aluminum-, Zinc-, Magnesium-, and Calcium-Hydrogen Bonds to Bent {CuL2} Fragments: Heavy σ Complexes of the Lightest Coinage Metal
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DOI：
10.1021/acs.inorgchem.7b00182
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发表时间：
2017-08-07
影响因子：
4.6
通讯作者：
Crimmin, Mark R.
中科院分区：
文献类型：
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作者：
Hicken, Alexandra;White, Andrew J. P.;Crimmin, Mark R.
制备了一系列铜(I)配合物，这些配合物带有缺电子-二氯二胺酸配体。研究包括[{{ArNC(CR3)}(2)CH)-Cu（eta(2)-甲苯）(n)] (Ar = Mes, R = F, n = 0.5,[1(2)中心dot tol]；Ar = C6F5, R = Me, n = 1, [2]；Ar = 2,6- cl2c6h3, R = H, n = 0.5，[32中心点tol])。[1-3(n)中心点tol]与硼烷、烷烷、氢化锌、氢化镁和氢化钙反应生成相应的a配合物（[1-3中心点B]、[3中心点B']、[3中心点Al]、[3]）。[1-3个中心点Zn]，[1个中心点Mg]，[1个中心点Ca])。这些物质都是可逆形成的，与溶液中的芳烃溶剂化物处于平衡状态。除了钙配合物外，所有配合物都用单晶x射线衍射研究进行了表征。在溶液中，铝、锌、镁和钙衍生物的西格玛氢化物在-0.12和-1.77 ppm （C6D6或甲苯-d(8),193-298 K）之间共振。对于sigma-硼烷配合物，氢化物在2 - 3.5 ppm （C6D6, 298 K）之间观察到单一共振，桥接氢化物和末端氢化物在核磁共振时间尺度上即使在193 K下也能快速交换，通过范特霍夫分析得到的溶液动力学定量结果显示，δ H度值较小，as值为负值，符合弱结合和不涉及铜类聚集的可逆过程。供体-受体复合物可以用Dewar-Cliatt-Duncanson模型来合理化。密度泛函理论计算表明，铜碎片的sigma -M-H（或E-H）电子在4基轨道（LUMO或LUMO+1）上的供能伴随着d（xz）基轨道（HOMO或HOMO-1）向sigma*-M-H（或E-H）轨道的弱反向供能。
A series of copper(I) complexes bearing electron-deficient beta-diketiminate ligands have been prepared. The study includes [{{ArNC(CR3)}(2)CH)-Cu(eta(2)-toluene)(n)] (Ar = Mes, R = F, n = 0.5, [1(2)center dot tol]; Ar = C6F5, R = Me, n = 1, [2 center dot tol]; Ar = 2,6-Cl2C6H3, R = H, n = 0.5, [32 center dot tol]). Reactions of [1-3(n)center dot tol] with boranes, alanes, a zinc hydride, a magnesium hydride, and a calcium hydride generate the corresponding a complexes ([1-3 center dot B], [3 center dot B'], [3 center dot Al], [3.Al'], [1-3 center dot Zn], [1 center dot Mg], and [1 center dot Ca]). These species all form reversibly, being in equilibrium with the arene solvates in solution. With the exception of the calcium complex, the complexes have all been characterized by single-crystal X-ray diffraction studies. In solution, the sigma-hydride of the aluminum, zinc, magnesium, and calcium derivatives resonates between -0.12 and -1.77 ppm (C6D6 or toluene-d(8),193-298 K). For the sigma-borane complexes, the hydrides are observed as a single resonance between 2 and 3.5 ppm (C6D6, 298 K) and bridging and terminal hydrides rapidly exchange on the NMR time scale even at 193 K Quantification of the solution dynamics by van't Hoff analysis yields expectedly small values of Delta H degrees and negative values of AS consistent with weak binding and a reversible process that does not involve aggregation of the copper species. The donor acceptor complexes can be rationalized in terms of the Dewar-Cliatt-Duncanson model. Density functional theory calculations show that the donation of sigma-M H (or E-H) electrons into the 4s-based orbital (LUMO or LUMO+1) of the copper fragment is accompanied by weak back-donation from a d(xz)-based orbital (HOMO or HOMO-1) into the sigma*-M-H (or E-H) orbital.