Solid State NMR Studies of H/CO Dynamics on Multi-nuclear Transition-metal Clusters

多核过渡金属团簇 H/CO 动力学的固态核磁共振研究

• 批准号: 09640606
• 负责人: EGUCHI Taro
• 金额: $ 2.24万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640606/
• 关键词: Transition-metal cluster; Carbonyl; Hydride; Dynamics; Solid state NMR; Crystal structure; 多核遷移金属クラスター; スピン-格子緩和時間

Variable temperature, MAS and wide-line solid state NMR measurements have been carried out on H_4Ru_4(CO)_<12> and H_4Ru_4(CO)_<12>{P(OMe)_3}. The variation of spin-lattice relaxation time (Ti) and linewidth at half intensity (DELTAupsilonl/2) of the hydride resonance with temperature for both samples are very similar and suggests that a common hydride movement occurs with Ealpha=17 * 2 LI mo1^<-1>. We attribute this movement to a 2-site H-flip about H-occupied Ru-Ru edges which preserves the site symmetry of the crystals.The molecular structures of(NMe_4)4-x[H_xNi_<12>(CO) _<21>].S (x=1, S=Me2CO ; x=2, S=1/2 THF) are reported. Both anions are similar and consist of a central Ni_6(CO)_3(mu-CO)_6 - layer flanked on both sides by two Ni_3(CO)_3(mu-CO)_3-layers such that the Ni_<12>-fragrpent is hexagonal close-packed. The separation between the central Ni_6-plane (B) and the two outer Ni_3-planes (A, C) is consistent with H-occupancy of either one (x=1) or both (x=2) of the two octahedra … More l metal cavities. Variable temperature solid state ^1H MAS and ^<13>C CP/MAS NMR spectra are reported for both clusters. For the dihydride, the solid state ^1H and ^<13>C NMR spectra remain unchanged from low to room temperature and are consistent with the X-ray structure ; at room temperature, there are two hydride resonances consistent with them being on the plane of symmetry on opposite sides of the Ni_6-layer and the highfield shift is consistent with them not being in the center of the Ni_6- octahedral cavity. For [H_2Ni_<12>(CO)_<12>]^<2->, there is close agreement between the solution and solid state ^<13>CO chemical shifts except for the inner bridging carbonyls which appear in solution as one resonance whereas in the solid state occur as two resonances due to the bridging CO's being either above or below the Ni6-plane. At higher temperatures, there is evidence for H-movement (probably oscillation about the plane of symmetry) but ^<13>C spectra indicate that the CO's remain essentially static. For the monohydride, three of the bridging CO's are almost co-planar with the Ni_6-plane, one, C6, is significantly bent towards the hydride and two CO's are in intermediate positions ; the low temperature solid state ^<13>CO NMR spectra appear to be entirely consistent with this structure. At room temperature, there is some coalescence of the ^<13>CO resonances, suggesting some carbonyl-movement, but there is no evidence for H-migration from the occupied interstitial octahedral site to the unoccupied octahedral site. Less

本文对H_4Ru_4（CO）_3<12>和H_4Ru_4（CO）_<12>{P（OMe）_3}进行了变温、MAS和宽线固体NMR测量。对于两种样品，氢化物共振的自旋-晶格弛豫时间（Ti）和半强度处的线宽（Δ 1/2）随温度的变化非常相似，并且表明在Ealpha=17 * 2LImo 1/2时发生共同的氢化物运动<-1>。本文报道了（NMe_4）_4-x[H_xNi_<12>（CO）_<21>]·S（x=1，S= Me_2CO; x=2，S=1/2 THF）的分子结构。这两种阴离子结构相似，都是由一个中心Ni_6（CO）_3（mu-CO）_6层和两侧的两个Ni_3（CO）_3（mu-CO）_3层组成，因此Ni_<12>-芳香族化合物是六方密排的。中心Ni_6面（B）和两个外Ni_3面（A，C）之间的分离与两个八面体中的一个（x=1）或两个（x=2）的H占据一致 ...更多信息 l金属腔。这两个团簇的变温固态^1H MAS和^<13>C CP/MAS NMR谱都有报道。对于二氢化物，固态^1H和1H <13>NMR谱从低温到室温保持不变，并且与X射线结构一致;在室温下，存在两个氢化物共振，这与它们位于Ni_6层相对两侧的对称平面上一致，并且高场位移与它们不在Ni_6八面体空腔的中心一致。对于[H_2Ni_<12>（CO）_<12>]~（2+）<2->，<13>除了内桥羰基在溶液中出现一个共振，而在固态中出现两个共振外，溶液和固态的~（2+）CO化学位移基本一致。在更高的温度下，有证据表明H-运动（可能是关于对称平面的振荡），但^<13>C光谱表明CO基本上保持静止。对于一氢化物，三个桥连CO几乎与Ni_6面共面，一个C_6明显向氢化物弯曲，两个CO位于中间位置，低温固态~ <13>1HNMR谱似乎与这种结构完全一致。在室温下，有一些聚结的^<13>CO共振，表明一些羰基运动，但没有证据表明H-迁移从占据间隙八面体网站的未占用的八面体网站。少

项目成果

Taro Eguchi and Brian T.Heaton.: "“Comparative Solid State and Solution NMR Structural and Dynamic Studes on Tetra-and Higher-Nuclearity Transition Metal Carbonyl Clusters"" J.Chem.Soc.Dalton Trans.(Submitted.).

Taro Eguchi 和 Brian T.Heaton.：“关于四核和更高核过渡金属羰基团簇的比较固态和溶液 NMR 结构和动态研究””J.Chem.Soc.Dalton Trans.（已提交）。

Taro Eguchi and Brian T.Heaton: ""Comparative Solid State and Solution NMR Structural and Dynamic Studies on Tetra-and Higher-Nuclearity Transition Metal Carbonyl Clusters"" J.Chem.Soc.Dalton Trans. (Submitted.).

Taro Eguchi 和 Brian T.Heaton：“四核和更高核过渡金属羰基团簇的比较固态和溶液 NMR 结构和动态研究”J.Chem.Soc.Dalton Trans。

Rachel A.Harding, Hirokazu Nakayama, Taro Eguchi, Nobuo Nakamura, Brian T.Heaton, and Anthony K.Smith: ""H-Motion in H_4Ru_4(CO)_<12-x>L_x (x=0,1 ; L=P(OMe)_3) from Solid State NMR Studies"" Polyhedron. 17(17). 2857-2863 (1998)

Rachel A.Harding、Hirokazu Nakayama、Taro Eguchi、Nobuo Nakamura、Brian T.Heaton 和 Anthony K.Smith：“”H_4Ru_4(CO)_<12-x>L_x (x=0,1 ; L) 中的 H 运动

Rachel A.Harding,et al.: "“H-Motion in H_4Ru_4(CO)_<12-x>L_x(x=0,1 ; L=P(OMe)_3)from Solid State NMR Studies"" Polyhedron. 17,(17). 2857-2863 (1998)

Rachel A. Harding 等人：“来自固态 NMR 研究的 H_4Ru_4(CO)_<12-x>L_x(x=0,1 ; L=P(OMe)_3) 中的 H 运动”” 多面体。 17，（17）2857-2863（1998）。

J.V. Barkley et al.: "Solid State Studies (X-ray and 'H, ^<13>C NMR) on (NMe_4)_<4-x> [H_2Ni_<12>(CO)_<21>]・S (X=1,S=Me_2CO; X=2, S=1/2THF" J. Organometal. Chem.573. 254-260 (1999)

J.V. Barkley 等人：“(NMe_4)_<4-x> [H_2Ni_<12>(CO)_<21>]·S 的固态研究（X 射线和 H, ^<13>C NMR） (X=1,S=Me_2CO;X=2,S=1/2THF" J. Organometal. Chem.573. 254-260 (1999)