The transition from nanocluster to nanocrystal is a central issue in nanoscience. The atomic structure determination of metal nanoparticles in the transition size range is challenging and particularly important in understanding the quantum size effect at the atomic level. On the basis of the rationale that the intra- and interparticle weak interactions play critical roles in growing high-quality single crystals of metal nanoparticles, we have reproducibly obtained ideal crystals of Au₁₄₄(SR)₆₀ and successfully solved its structure by x-ray crystallography (XRC); this structure was theoretically predicted a decade ago and has long been pursued experimentally but without success until now. Here, XRC reveals an interesting Au₁₂ hollow icosahedron in thiolated gold nanoclusters for the first time. The Au-Au bond length, close to that of bulk gold, shows better thermal extensibility than the other Au-Au bond lengths in Au₁₄₄(SR)₆₀, providing an atomic-level perspective because metal generally shows better thermal extensibility than nonmetal materials. Thus, our work not only reveals the mysterious, long experimentally pursued structure of a transition-sized nanoparticle but also has important implications for the growth of high-quality, single-crystal nanoparticles, as well as for the understanding of the thermal extensibility of metals from the perspective of chemical bonding.

中文翻译：

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通过X射线晶体学揭示了长期追求的Au144结构。

从纳米团簇到纳米晶体的转变是纳米科学中的中心问题。确定过渡尺寸范围内的金属纳米粒子的原子结构具有挑战性，对于理解原子级的量子尺寸效应特别重要。基于粒子内和粒子间弱相互作用在生长金属纳米粒子的高质量单晶中起关键作用的基本原理，我们可再现地获得了理想的Au ₁₄₄（SR）₆₀晶体，并通过X射线成功解析了其结构晶体学（XRC）；这种结构理论上是在10年前预测的，长期以来一直通过实验进行尝试，但直到现在都没有成功。在这里，XRC揭示了一个有趣的Au ₁₂首次在硫醇化的金纳米簇中形成空心二十面体。Au-Au键长接近于大块金，与Au ₁₄₄（SR）_60中的其他Au-Au键长相比，具有更好的热延展性，提供了原子级的观点，因为金属通常比非金属材料具有更好的热延展性。因此，我们的工作不仅揭示了过渡尺寸纳米颗粒的神秘的，长期的实验追求，而且对高质量单晶纳米颗粒的生长以及对金属的热扩展性的理解具有重要意义。从化学键的角度来看。