Chiu Tzu-Hao, Liao Jian-Hong, Gam Franck, Wu Ying-Yann, Wang Xiaoping, Kahlal Samia, Saillard Jean-Yves, Liu C W
Department of Chemistry, National Dong Hwa University, Hualien 974301, Taiwan (Republic of China).
CNRS, ISCR-UMR 6226, Univ Rennes, Rennes F-35000, France.
J Am Chem Soc. 2022 Jun 15;144(23):10599-10607. doi: 10.1021/jacs.2c03715. Epub 2022 Jun 2.
Recent reports on hydride-doped noble metal nanoclusters strongly suggest that the encapsulated hydride is a part of the core, but no accurate location of the hydride could be experimentally proved, so far. We report herein a hydride-doped eight-electron platinum/silver alloy nanocluster in which the position of four-coordinated hydride was determined by neutron diffraction for the first time. X-ray structures of [PtHAg(dtp/desp)] (dtp = SP(OPr), ; dsep = SeP(OPr), ) describe a central platinum hydride (PtH) unit encapsulated within a distorted Ag icosahedron, the resulting (PtH)@Ag core being stabilized by an outer sphere made up of 7 capping silver atoms and 12 dichalcogenolates. Solid-state structures of and differ somewhat in the spatial configuration of their outer spheres, resulting in overall different symmetries, and , respectively. Whereas the multi-NMR spectra of in solution at 173 K reveal that the structure of symmetry is the predominant one, H and Pt NMR spectra of at the same temperature disclose the presence of isomers of both and symmetry. DFT calculations found both isomers to be very close in energy, supporting the fact that they co-exist in solution. They also show that the [PtH@Ag] kernel can be viewed as a closed-shell core, the μ-hydride electron contributing to its eight-electron count. On the other hand, the 1s(H) orbital contributes only moderately to the orbitals, being mainly involved in the building of a Pt-H bonding electron pair with the 5(Pt) orbital.
最近关于氢化物掺杂贵金属纳米团簇的报道有力地表明，封装的氢化物是核心的一部分，但到目前为止，氢化物的准确位置尚未通过实验得到证实。我们在此报告一种氢化物掺杂的八电子铂/银合金纳米团簇，其中首次通过中子衍射确定了四配位氢化物的位置。[PtHAg(dtp/desp)]（dtp = SP(OPr)，；dsep = SeP(OPr)，）的X射线结构描述了一个中心氢化铂（PtH）单元封装在一个扭曲的银二十面体中，所得的（PtH）@Ag核心由由7个封端银原子和12个二硫醇盐组成的外层稳定。 和 的固态结构在其外层的空间构型上略有不同，分别导致整体不同的对称性 和 。虽然 在173 K溶液中的多核磁共振光谱表明 对称性结构是主要的，但在相同温度下 的氢和铂核磁共振光谱揭示了 对称性和 对称性异构体的存在。密度泛函理论计算发现这两种异构体的能量非常接近，支持它们在溶液中共存的事实。计算还表明，[PtH@Ag]核可以被视为一个闭壳 核心，μ-氢化物电子对其八电子计数有贡献。另一方面，1s(H)轨道对 轨道的贡献仅为中等程度，主要参与与5(Pt)轨道形成Pt-H键电子对。
