Methylaluminum-supported rare-earth-metal dihydrides.-猫眼课题宝

DOI：

10.1002/anie.201306783

发表时间：

2013-12

期刊：

Angewandte Chemie

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

Christoph Schädle;Dorothea Schädle;K. Eichele;R. Anwander

结合大的稀土金属（Ln）中心与最小的阴离子配体H2O（H2O）的化合物继续在基础化学和应用化学中提出具有挑战性的问题。[1]固态二元LnHx相（例如，导致金属行为）以及配体支持的分子对应物（揭示独特的簇化学，参见支持信息）中的固有键合特性一直是广泛研究的焦点。此外，异质结固态材料，如Ni 5LaHx，特征批准的可再充电电池组件，或如LnAlH 6（由LnCl 3和NaAlH 4通过释放氢获得），被讨论为中温储氢材料。[2]另一方面，对可溶性分子生物学的探索引发了巨大的研究努力。与此同时，单和双配位体衍生物“L2 LnH”和“LLnH 2”（L=单阴离子配体）分别在各种化学计量和催化转化中起着至关重要的作用，[3]而[LnH 3（Do）x]型络合物（Do=中性供体配体）仍然难以捉摸。虽然单氢化物络合物可以作为单体存在，例如[（C5 H2 tBu 3）2CeH]，[4]二氢物种“LLnH 2”，每个镧系元素中心仅携带一个辅助配体，倾向于形成含有少至两个[5]和多达六个镧系金属中心的多核络合物（参见支持信息）。[6]几种类型的辅助配体已被用于稳定低核性的络合物，包括空间要求高的配体衍生物，如C5 Me 4SiMe 3 [6]三（吡唑基）硼酸酯，[7]四氮杂环酰胺，[8]双（膦基苯基）酰胺钳，[5]和吡啶基酰胺[9]配体以及螯合二酰胺基配体（参见支持信息）。[10]然而，迄今为止，单体稀土金属二氢化物的合成并不成功。（3-叔丁基-5-甲基吡唑基）硼酸配体（TptBu，Me）以稳定诸如烷基、[11]卡宾、[12]酰胺、[11b]卤化物、[11，[13]或[14]，并且还能够使用Tp配体的体积较小的二甲基、二异丙基或未取代的衍生物获得镧系元素二氢化物络合物，但是报道了对于体积较大的TptBu，Me配体形成产物的混合物

Compounds combining the large rare-earth-metal (Ln) centers with the smallest anionic ligand, HÀ (hydrido), continue to pose challenging questions both in fundamental and applied chemistry.[1] The inherent bonding properties in solid-state binary LnHx phases (eg, causing metallic behavior) as well as in ligand-supported molecular counterparts (revealing unique cluster chemistry, see Supporting Information) have been the focus of extensive research. Moreover, heterobimetallic solid-state materials, such as Ni5LaHx, feature approved rechargeable battery components or, such as LnAlH6 (obtained from LnCl3 and NaAlH4 by the release of hydrogen), are discussed as intermediate-temperature hydrogen-storage materials.[2] On the other hand, the quest for soluble molecular hydrides has triggered immense research efforts. In the meantime, mono and dihydrido derivatives “L2LnH” and “LLnH2”(L= monoanionic ligand), respectively, are assigned a crucial role in a variety of stoichiometric and catalytic transformations,[3] whereas complexes of type [LnH3 (Do) x](Do= neutral donor ligand) are still elusive. While mono hydride complexes can exist as monomers, eg,[(C5H2tBu3) 2CeH],[4] dihydrido species “LLnH2”, carrying only one ancillary ligand per lanthanide center, tend to form polynuclear complexes (see Supporting Information) containing as few as two [5] and up to six lanthanide metal centers.[6] Several types of ancillary ligands have been employed in an effort to stabilize complexes of low nuclearity, including sterically demanding cyclopentadienyl derivatives such as C5Me4SiMe3[6] tris (pyrazolyl) borato scorpionates,[7] tetraazacycloamido,[8] bis (phosphinophenyl) amido pincer,[5] and pyridylamido [9] ligands as well as chelating diamido ligands (see Supporting Information).[10] However, the synthesis of a monomeric rare-earth-metal dihydride was not successful to date.The group of Takats used the sterically demanding hydrotris (3-tert-butyl-5-methylpyrazolyl) borato ligand (TptBu, Me) to stabilize Ln2+ centers in species such as alkyls,[11] carbenes,[12] amides,[11b] halides,[11, 13] or hydrides [14] and was also able to obtain lanthanide dihydride complexes using the less-bulky dimethyl, diisopropyl, or unsubstituted derivative of the Tp ligand, but reported the formation of a mixture of products for the more bulky TptBu, Me ligand

Methylaluminum-supported rare-earth-metal dihydrides.

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