CNR-ISOF, via Gobetti 101, 40129 Bologna, Italy.
Nanoscale. 2018 Dec 13;10(48):23018-23026. doi: 10.1039/c8nr07109h.
Metal-organic composites are of great interest for a wide range of applications. The control of their structure remains a challenge, one of the problems being a complex interplay of covalent and supramolecular interactions. This paper describes the self-assembly, thermal stability and phase transitions of ordered structures of silver atoms and thiol molecules spanning from the molecular to the mesoscopic scale. Building blocks of molecularly defined clusters formed from 44 silver atoms, each particle coated by a monolayer of 30 thiol ligands, are used as ideal building blocks. By changing solvent and temperature it is possible to tune the self-assembled 3D crystals of pristine nanoparticles or, conversely, 2D layered structures, with alternated stacks of Ag atoms and thiol monolayers. The study investigates morphological, chemical and structural stability of these materials between 25 and 300 °C in situ and ex situ at the nanoscale by combining optical and electronic spectroscopic and scattering techniques, scanning probe microscopies and density-functional theory (DFT) calculations. The proposed wet-chemistry approach is relatively cheap, easy to implement, and scalable, allowing the fabricated materials with tuned properties using the same building blocks.
金属有机复合材料在广泛的应用中具有重要的意义。对其结构的控制仍然是一个挑战，其中一个问题是共价和超分子相互作用的复杂相互作用。本文描述了从分子到介观尺度上银原子和硫醇分子有序结构的自组装、热稳定性和相变。由 44 个银原子组成的分子定义的团簇的构建块，每个粒子都涂有一层 30 个硫醇配体，被用作理想的构建块。通过改变溶剂和温度，可以调节原始纳米粒子的自组装 3D 晶体，或者相反，可以调节交替堆积的 Ag 原子和硫醇单层的 2D 层状结构。该研究通过结合光学和电子光谱和散射技术、扫描探针显微镜和密度泛函理论（DFT）计算，原位和非原位在纳米尺度上研究了这些材料在 25 至 300°C 之间的形态、化学和结构稳定性。所提出的湿化学方法相对便宜、易于实施且可扩展，允许使用相同的构建块制造具有可调性能的材料。
