Regium bonds between Mn clusters (M = Cu, Ag, Au and n = 2-6) and nucleophiles NH3 and HCN.
Regium bonds between Mn clusters (M = Cu, Ag, Au and n = 2-6) and nucleophiles NH3 and HCN.
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DOI：
10.1039/c8cp03883j
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发表时间：
2018-09
期刊：
影响因子：
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通讯作者：
W. Zierkiewicz;M. Michalczyk;S. Scheiner
中科院分区：
文献类型：
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作者：
W. Zierkiewicz;M. Michalczyk;S. Scheiner
铸币金属（或金属）原子（Cu, Ag, Au）簇Mn （n ~ 6）的最稳定的几何形状都是平面的，并采用尽可能低的自旋多重性。因此，具有偶数个M原子的团簇是单重态，而具有奇数个n原子的团簇是开壳重态。对每个簇的分子静电势（MEP）的检查提供了一个强有力的迹象，表明最有可能被接近的亲核试剂攻击的位置，通常是两个位置中的一个。亲核试剂（NH3或HCN）最倾向于接近每个簇的一个特定的M原子，而不是键的中点或面。在闭壳团簇中，相互作用能高度依赖于MEP的强度，但在本工作中研究的开壳体系中，这种相关性逐渐减弱。相互作用的强度也与亲核试剂的碱度密切相关。态键能可大于30 kcal mol-1，并趋向于Au > Cu b> Ag的顺序。这些相互作用能量在很大程度上来自库仑引力，轨道相互作用的贡献较小。
The most stable geometries of the coinage metal (or regium) atom (Cu, Ag, Au) clusters Mn for n up to 6 are all planar, and adopt the lowest possible spin multiplicity. Clusters with even numbers of M atoms are thus singlets, while those with odd n are open-shell doublets. Examination of the molecular electrostatic potential (MEP) of each cluster provides strong indications of the most likely site of attack by an approaching nucleophile, generally one of two positions. A nucleophile (NH3 or HCN) most favorably approaches one particular M atom of each cluster, rather than a bond midpoint or face. In the closed-shell clusters, the interaction energies are highly dependent upon the intensity of the MEP, but this correlation fades for the open-shell systems studied in this work. The strength of the interaction is also closely related to the basicity of the nucleophile. Regium bond energies can be more than 30 kcal mol-1 and tend to follow the Au > Cu > Ag order. These interaction energies are in large part derived from Coulombic attraction, with a smaller orbital interaction contribution.