Developing Two High-Nuclearity Ag Nanoclusters with Temperature-Sensitive Fluorescence Properties

Abstract

Two new high-nuclearity silver nanopolyclusters, templated with chromate and molybdate, were synthesized through a simple synthesis process. The structure of the nanoclusters, with the formulas (CrO4)@Ag19(C≡CPh)7(Ph2PO2)8(H2O)‧(BF4)2‧CH3OH (YL-1) and (MoO4)@Ag19(C≡CPh)9(Ph2PO2)7‧(OTf)‧CH3OH (YL-5), were determined by single-crystal X-ray analysis and confirmed using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electrospray ionization mass spectrometry (ESI-MS), and Fourier transform infrared spectroscopy (FT IR). Absorption and luminescence properties of the nanoclusters were studied. However, only nanocluster YL-5 showed temperature-dependent green fluorescence at 77 K, with a maximum emission wavelength of 497 nm. The excitation properties of the two silver nanoclusters were investigated by Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. The synthesis conditions of both nanoclusters are similar except that two different templates were used in their synthesis process. Therefore, the influence of template molecules on the self-assembly process and the creation of different structures, as well as the emergence of new properties based on the nature of the template, is interesting and noteworthy.