In recent years, metal–organic frameworks (MOFs) have become an area of intense research interest because of their adjustable pores and nearly limitless structural diversity deriving from the design of different organic linkers and metal structural building units (SBUs). Among the recent great challenges for scientists include switchable MOFs and their corresponding applications. Switchable MOFs are a type of smart material that undergo distinct, reversible, chemical changes in their structure upon exposure to external stimuli, yielding interesting technological applicability. Although the process of switching shares similarities with flexibility, very limited studies have been devoted specifically to switching, while a fairly large amount of research and a number of Reviews have covered flexibility in MOFs. This Review focuses on the properties and general design of switchable MOFs. The switching activity has been delineated based on the cause of the switching: light, spin crossover (SCO), redox, temperature, and wettability.

In order to study the charge effect on the formation of an anion-templated silver cluster, a trivalent tetrahedral anion was incorporated into the silver assembly. A 26-nuclear silver cluster was prepared, and its structure was confirmed by single-crystal X-ray diffraction. Also, the resulting structure was characterized by powder X-ray diffraction data. Its light absorption and photoluminescent properties were studied by solid-state UV diffuse-reflectance and fluorescence spectroscopy. Compared with the other reported silver clusters with tetrahedral anion templates, the more negative VO 4 3− anion led to the formation of a bigger silver cluster. Also, the supramolecular motif O−H(CH 3 OH)•••O(trifluoroacetate) was confirmed on the cluster surface for the first time.

Advancement of the synthesis and control of the self-assembly process of new high-nucleus silver clusters with desired structures is important for both the material sciences and the many applications. Herein, three new silver clusters, 20-, 22-, and 8-nucleus, based on alkynyl ligands were constructed and their structures were confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, and Fourier-transform infrared spectroscopy (FT-IR). For the first time, the trivalent tetrahedron anion of AsO 4 3− , as a template, and the surface ligand of Ph 2 PO 2 H, with new coordination modes, were employed in preparation of the silver clusters. The role of surface ligands and template anions in the size and structure of the clusters was investigated. The presence of the template in the structure of the clusters led to the formation of the high-nucleus clusters. Also, in this report, it was shown that the participation of the template in the assembly of a cluster can be controlled by the surface ligands. UV−vis absorption and luminescent properties of the clusters and the thermal stability of the 8-nucleus cluster were also studied.

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The first silver nanocluster with an octahedral template of TeO6 6– was synthesized as a neutral 36-nucleus nanocluster, and its structure was demonstrated using single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, electrospray ionization mass spectrometry, and X-ray photoelectron spectroscopy. The peripheral ligands of the cagelike skeleton of the nanocluster are CF3COO– and tBuCC–. During the synthesis, the TeO6 6– template arranged the nanocluster, and a 36-nucleus nanocluster was formed. The effect of the template nature was displayed on the structural features of the nanocluster in comparison with an 8-nucleus cluster, with the same synthesis conditions. The photoluminescence and UV–vis absorption analyses of the nanocluster were also investigated. The nanocluster displayed near-infrared luminescence emission at 690 nm.

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