Assembly of Atomically Precise Silver Nanoclusters into Nanocluster-Based Frameworks

Abstract

Here, we demonstrate an approach to synthesizing and structurally characterizing three atomically precise anion-templated silver thiolate nanoclusters, two of which form one-and two-dimensional structural frameworks composed of bipyridine-linked nanocluster nodes (referred to as nanocluster-based frameworks, NCFs). We describe the critical role of the chloride (Cl − ) template in controlling the nanocluster's nuclearity with atomic precision and the effect of a single Ag atom difference in the nanocluster's size in controlling the NCF dimensionality, modulating the optical properties, and improving the thermal stability. With atomically precise assembly and size control, nanoclusters could be widely adopted as building blocks for the construction of tunable cluster-based framework materials.

Ligand engineering to achieve enhanced ratiometric oxygen sensing in a silver cluster-based metal-organic framework

“…The significant decrease in the ligand-based Fl lifetimes of Ag 12 bpy-NH 2 from 3.59 to 0.37 ns, which is accompanied by a considerable increase in the Ph lifetime from 0.2 μs to 3.12 ms (Table 1), suggested the occurrence of an efficient ISC process from the lowest singlet to the lowest triplet excited states (vide infra). The 15,000-fold enhancement in the Ph lifetime is an unprecedented phenomenon among luminescent MOFs [19][20][21][22][23][24][25][26][27][28][33][34][35][36][37][38] and metal clusters [39][40][41][42][43] , even in metal-containing phosphors 12,13,[44][45][46] , which means that the triplet excited state(s) of Ag 12 bpy-NH 2 is capable of responding to oxygen molecules with a sensitivity of one-15,000th of the original sensitivity of unsubstituted Ag 12 bpy if one merely considers the lifetime factor. Of course, this also presents a challenge for obtaining precise measurements in the range of hypoxia.…”

“…6). Ag 12 bpy-NH 2 , with an LOD as low as 0.11 ppm, is applicable for nearly anoxic systems with oxygen levels in the range of 0.1-24 ppm and has sensitivities that are orders of magnitude above those of conventional sensing MOFs [19][20][21][22][23][24][25][26][27][28][33][34][35][36][37][38] . Ag 12 bpy-NH 2 opens the door to completely new applications for monitoring oxygen in previously inaccessible concentration regions and is likely to become invaluable in diverse fields of science and technology.…”

“…Traditionally, dual emission in MOFs is mostly achieved with lanthanide ion or luminescent linker on a host MOF framework as one emissive center and a post-introduced luminescent species including lanthanide ion, dye or carbon dot as another emissive center, which make it difficult to realize ultrasensitive and ratiometric detection towards oxygen gas 11 . Silver-chalcogenolate-cluster-based metal-organic frameworks (SCC-MOFs) [33][34][35][36][37][38] , in which each SBU consists of tens of silver and chalcogen atoms, have become a new member of the MOF family. SCC-MOFs combine the advantages of silver clusters [39][40][41][42][43] and MOFs [8][9][10][11][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] ; SCC-MOFs have shown remarkably improved luminescent properties relative to discrete silver clusters and unique excellent luminescent responses for sensing gases and volatile organic compounds (VOCs) [33][34][35][36][37] .…”

Three‐dimensional Octameric Assembly of Icosahedral M13 Units in [Au8Ag57(Dppp)4(C6H11S)32Cl2]Cl and its [Au8Ag55(Dppp)4(C6H11S)34][BPh4]2 Derivative

“…Metal nanoclusters are an emerging class of promising nanomaterials owing to their atomically precise structures and intriguing properties . Because of the quantum size effect of the nanoclusters, variations in the assembly of the structures may induce tremendous variations on the properties of clusters . Therefore, the atomically precise, well‐defined nanoclusters provide ideal models for furthering our fundamental understanding of structure‐related properties .…”

Highly stable folic acid functionalized copper-nanocluster/silica nanoparticles for selective targeting of cancer cells

“…), have attracted extensive attention in bioimaging owing to their superior features including, facile synthesis, tunable emission wavelength, water dispersibility, excellent biocompatibility and low toxicity. [16][17][18] In particular, Cu-based NCs have gained immense research interests for the merits of available raw materials and relatively low cost of copper. 19,20 However, the CuNCs are typically coating with thiol-containing proteins or small molecules, which are usually susceptive to the external stimulus or the complex and varying biological environments, resulting in the aggregation/ oxidation of the CuNCs corresponding to the uorescence quenching.…”