Wen Qingqing, Feng Bin, Xiang Li, Leng Xuebing, Chen Yaofeng
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China.
Chongqing Key Laboratory of Green Synthesis and Applications, College of Chemistry, Chongqing Normal University, Chongqing 401331, P. R. China.
Inorg Chem. 2021 Sep 20;60(18):13913-13919. doi: 10.1021/acs.inorgchem.1c00686. Epub 2021 May 17.
While the chemistry of trivalent rare-earth metal hydrido complexes has been well developed in the past 40 years, that of the divalent rare-earth metal hydrido complexes remains in its infancy because of the synthetic challenge of such complexes. In this paper, we report the synthesis and structural characterization of a divalent ytterbium hydrido complex supported by a bulky β-diketiminato-based tetradentate ligand. This hydrido complex is a dimer containing two μ-hydrogen ligands, and it easily undergoes a hydrido shift reaction to form a new divalent ytterbium hydrido complex that contains only one hydrido bridge. Furthermore, this hydrido complex reacts with pyridine and pyridine derivatives, showing versatile reactivity [Yb-H addition to pyridine, hydrido shift to ancillary ligand, and ytterbium(II)-center-induced redox reaction with bipyridine]. This hydrido complex reacts with PhP═O, resulting in a P-C cleavage of PhP═O and an elimination of CH; on the other hand, the reaction with PhP═S is a hydrido coupling-based redox reaction. The reactions of this hydrido complex with 1 and 2 equiv of PhSSPh clearly indicate that the hydrido coupling-based redox reaction is prior to the ytterbium(II) oxidation-based redox reaction.
尽管三价稀土金属氢化物配合物的化学在过去40年中已得到充分发展，但由于二价稀土金属氢化物配合物合成上的挑战，其化学研究仍处于起步阶段。在本文中，我们报道了一种由庞大的β-二酮亚胺基四齿配体支撑的二价镱氢化物配合物的合成及结构表征。这种氢化物配合物是一种含有两个μ-氢配体的二聚体，并且它容易发生氢迁移反应，形成一种仅含一个氢桥的新型二价镱氢化物配合物。此外，这种氢化物配合物与吡啶及吡啶衍生物发生反应，表现出多样的反应活性[向吡啶进行Yb-H加成、氢迁移至辅助配体以及二价镱中心引发的与联吡啶的氧化还原反应]。这种氢化物配合物与PhP═O反应，导致PhP═O发生P-C键断裂并消除CH；另一方面，与PhP═S的反应是基于氢偶联的氧化还原反应。这种氢化物配合物与1当量和2当量的PhSSPh的反应清楚地表明，基于氢偶联的氧化还原反应先于基于二价镱氧化的氧化还原反应。
