Department of Chemistry, University of Alberta, Edmonton, AB T6G2G2, Canada.
Université de Toulouse, CNRS, INSA, UPS, UMR 5215, LPCNO, 135 avenue de Rangueil, F-31077 Toulouse, France.
Inorg Chem. 2023 Jul 17;62(28):11179-11187. doi: 10.1021/acs.inorgchem.3c01319. Epub 2023 Jul 6.
The synthesis, characterization, and solid-state structure of bulky alkoxy- and aryloxy-supported yttrium polynuclear hydrides are reported. Hydrogenolysis of the supertrityl alkoxy anchored yttrium dialkyl, Y(OTr*)(CHSiMe)(THF) () (Tr* = tris(3,5-di--butylphenyl)methyl), resulted in the clean conversion to the tetranuclear dihydride, [Y(OTr*)H(THF)] (). X-ray analysis revealed a highly symmetrical structure (̅ site symmetry) with the four Y atoms located on the corners of a compressed tetrahedron, each bonded to an OTr* and tetrahydrofuran (THF) ligand and the cluster held together by four face-capping, μ-H, and four edge-bridging, μ-H, hydrides. DFT calculations on the full system with and without THF, but also on model systems, clearly show that the structural preference for complex is controlled by the presence and coordination of THF molecules. Contrary to the exclusive formation of the tetranuclear dihydride, hydrogenolysis of the bulky aryloxy yttrium dialkyl, Y(OAr*)(CHSiMe)(THF) () (Ar* = 3,5-di--butylphenyl) gave a mixture of the analogous tetranuclear and trinuclear, [Y(OAr*)H(THF)], polyhydride, . Similar results, i.e., a mixture of tetra-/tri-nuclear products, were obtained from hydrogenolysis of the even bulkier Y(OAr)(CHSiMe)(THF) compound. Experimental conditions were established to optimize the production of either the tetra- or trinuclear products. X-ray structure of revealed a triangular array of three yttrium atoms with two face-capping μ-H and three edge-bridging μ-H hydrides, with one yttrium bonded to two aryloxy ligands while the other two have a complement of one aryloxy and two THF ligands; the solid-state structure is close to being C symmetric, with the C axis running through the unique Y and unique μ-H hydride. As opposed to , which shows distinct H NMR resonances for μ/ μ-H (δ = 5.83/6.35 ppm, respectively), no hydride signals for were observed at room temperature, indicating hydride exchange on the NMR time scale. Their presence and assignment were secured at -40 °C from H SST (spin saturation) experiment.
报道了大位阻烷氧基和芳氧基支撑的钇多核氢化物的合成、表征和固态结构。超三苯甲基烷氧基锚定的钇二烷基 Y(OTr*)(CHSiMe)(THF) ()（Tr*=三（3,5-二叔丁基苯基）甲基）的氢解反应导致了四核二氢化物 [Y(OTr*)H(THF)] () 的干净转化。X 射线分析显示出高度对称的结构（̅点群对称性），其中四个 Y 原子位于压缩四面体的角上，每个原子都与一个 OTr和四氢呋喃（THF）配体键合，簇由四个面桥接的 μ-H 和四个边缘桥接的 μ-H 氢化物连接在一起。对完整体系（含或不含 THF）以及模型体系的密度泛函理论（DFT）计算清楚地表明，配合物的结构偏好由 THF 分子的存在和配位控制。与四核二氢化物的专一地形成相反，大位阻芳氧基钇二烷基 Y(OAr)(CHSiMe)(THF) ()（Ar*=3,5-二叔丁基苯基）的氢解反应得到了类似的四核和三核产物的混合物，[Y(OAr*)H(THF)]。类似的结果，即四-/三核产物的混合物，也从更位阻的 Y(OAr)(CHSiMe)(THF)化合物的氢解反应中获得。实验条件的建立是为了优化四核或三核产物的产量。的 X 射线结构显示出三个钇原子的三角形排列，其中两个是面桥接的 μ-H，三个是边缘桥接的 μ-H 氢化物，一个钇原子与两个芳氧基配体键合，而另外两个有一个芳氧基和两个 THF 配体；固态结构接近 C 对称，C 轴穿过独特的 Y 和独特的 μ-H 氢化物。与显示出明显的 μ/ μ-H 氢核共振（δ=5.83/6.35 ppm）的不同，在室温下没有观察到的氢化物信号，表明在 NMR 时间尺度上发生了氢化物交换。通过在-40°C 下进行 H SST（自旋饱和）实验，确保了它们的存在并对其进行了归属。
