Entrapping Atomically Precise Clusters in Cyclodextrin-Functionalized Aminoclay Sheets: Synthesis and Enhanced Luminescence

In this article, a unique covalently linked aminoclay substrate, grafted with β-cyclodextrin (AC-CD), was prepared to entrap luminescent silver nanoclusters. Chemically synthesized aminoclay (AC) sheets grafted with β-cyclodextrins (β-CDs) were used to develop a supramolecular entity. Here, we grafted β-CD onto aminoclays using cyanuric chloride as a linker. The AC-CD material was thoroughly characterized using Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The grafting ratio of β-CD onto AC-CD was determined using the phenolphthalein inclusion protocol. The as-prepared functionalized clay (AC-CD) is an effective and attractive material for entrapping a luminescent silver chalcogenide cluster stabilized by 4-(t-butyl)benzyl mercaptan (Ag56Se13S15@SBB28 shortened as Ag2Se@SBB). The cluster AC-CD (AC-CD∩Ag2Se@SBB) supramolecular nanocomposite is based on specific host-guest interactions involving β-CD of AC-CD and SBB of a silver cluster. Entrapment of the cluster into the β-CD cavity was verified using optical absorption, luminescence spectroscopy, XRD, and TEM. The entrapment resulted in enhanced luminescence and stability of the cluster. Such a dispersible nanocomposite system exhibiting intense luminescence will be useful in creating novel materials for various applications such as sensors, optoelectronic devices, etc.