1D silver cluster-assembled materials act as a platform for selectively erasable photoluminescent switch of acetonitrile

Assembly of Copper Alkynyl Clusters into Dimensionally Diverse Coordinated Polymers Mediated by Pyridine Ligands

Surface ligands play crucial roles in modifying the properties of metal nanoclusters and stabilizing atomically precise structures, and also serve as vital linkers for constructing cluster-based coordination polymers. In this study, we present the results of the solvothermal synthesis of eight novel copper alkynyl clusters incorporating pyridine ligands using a one-pot method. The resulting compounds underwent characterization through elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), and single-crystal X-ray diffraction (SCXRD). Our observations revealed that distinct pyridine ligands with varying lengths and coordination sites exert significant influence on the structure and dimensionality of the clusters. The structural diversity of these clusters led to the formation of one-dimensional (1D), two-dimensional (2D), or dimer arrangements linked by seven pyridine bridging ligands. Remarkably, these complexes exhibited unique UV-vis absorption and photoluminescence properties, which were influenced by the specific bridging ligand and structural framework. Furthermore, density functional theory (DFT) calculations demonstrated the capability of the conjugated system in the pyridine ligand to impact the band gap of clusters. This study not only unveils the inherent structural diversity in coordination polymers based on copper alkynyl clusters but also offers valuable insights into harnessing ligand engineering for structural and property modulation.

Recent progress in atomically precise silver nanocluster-assembled materials

In the dynamic landscape of nanotechnology, atomically precise silver nanoclusters (Ag NCs) have emerged as a novel and promising category of materials with their fascinating properties and enormous potential. However, recent research endeavors have surged towards stabilizing Ag-based NCs, leading to innovative strategies like connecting cluster nodes with organic linkers to construct hierarchical structures, thus forming Ag-based cluster-assembled materials (CAMs). This approach not only enhances structural stability, but also unveils unprecedented opportunities for CAMs, overcoming the limitations of individual Ag NCs. In this context, this review delves into the captivating realm of atomically precise nitrogen-based ligand bonded Ag(I)-based CAMs, providing insights into synthetic strategies, structure-property relationships, and diverse applications. We navigate the challenges and advancements in integrating Ag(I) cluster nodes, bound by argentophilic interactions, into highly connected periodic frameworks with different dimensionalities using nitrogen-based linkers. Despite the inherent diversity among cluster nodes, Ag(I) CAMs demonstrate promising potential in sensing, catalysis, bio-imaging, and device fabrication, which all are discussed in this review. Therefore, gaining insight into the silver nanocluster assembly process will offer valuable information, which can enlighten the readers on the design and advancement of Ag(I) CAMs for state-of-the-art applications.

The structure and application portfolio of intricately architected silver cluster-assembled materials

Silver Cluster-Assembled Materials (SCAMs) represent a new frontier of crystalline extended solids hallmarked by their customizable structures, commendable stabilities, and unique physical/chemical properties. Since their discovery in 2017, the diversity of organic linkers has endowed SCAMs with ingenious architectures and the application scenario has expanded beyond photoluminescence sensing to environmental sustainability and biomedical applications. It is critically important to chronicle these recent key advances and review the progress of SCAMs that can enable translating the material discoveries into real implementation. Herein, we provide a succinct overview of the trajectory of SCAM research, with crucial insights into atomic-level structural correlations with the phenomena at the nanoscale and discuss the gaps and opportunities that are still open in addition to charting a roadmap for future research directions.

Silver Cluster Assembled Materials: A Model-Driven Perspective on Recent Progress, with a Spotlight on Ag12 Cluster Assembly

The exploration of individual nanoclusters is rapidly advancing, despite stability concerns. To address this challenge, the assembly of cluster nodes through linker molecules has been successfully implemented. However, the linking of the cluster nodes itself introduces a multitude of possibilities, especially when additional factors come into play. While this method proves effective in enhancing material stability, the specific reasons behind its success remain elusive. In our laboratory, we have undertaken extensive studies on Ag cluster-assembled materials. So, here our goal is to establish a model system that allows for the discernment of various factors, eliminating unnecessary complexities during the linking approach. So, we hope that the systematic discourse presented in here will contribute significantly to future endeavors, helping to set clear priorities, and provide solutions to concerns that arise when working with a model system.

Synthesis and luminescence properties of two silver cluster-assembled materials for selective Fe3+ sensing

Silver cluster-assembled materials (SCAMs) are emerging light-emitting materials with molecular-level structural designability and unique photophysical properties. Nevertheless, the widespread application scope of these materials is severely curtailed by their dissimilar structural architecture upon immersing in different solvent media. In this work, we report the designed synthesis of two unprecedented (4.6)-connected three-dimensional (3D) luminescent SCAMs, [Ag₁₂(S^tBu)₆(CF₃COO)₆(TPEPE)₆]_n (denoted as TUS 1), TPEPE = 1,1,2,2-tetrakis(4-(pyridin-4-ylethynyl)phenyl)ethene and [Ag₁₂(S^tBu)₆(CF₃COO)₆(TPVPE)₆]_n (denoted as TUS 2), TPVPE = 1,1,2,2-tetrakis(4-((E)-2-(pyridin-4-yl)vinyl)phenyl)ethene, composed of an Ag₁₂ cluster core connected by quadridentate pyridine linkers. Attributed to their exceptional fluorescence properties with absolute quantum yield (QY) up to 9.7% and excellent chemical stability in a wide range of solvent polarity, a highly sensitive assay for detecting Fe³⁺ in aqueous medium is developed with promising detection limits of 0.05 and 0.86 nM L^-1 for TUS 1 and TUS 2 respectively, comparable to the standard. Furthermore, the competency of these materials to detect Fe³⁺ in real water samples reveals their potential application in environmental monitoring and assessment.

Silver cluster-assembled materials for label-free DNA detection

Herein, we report two newly synthesized silver cluster-assembled materials (SCAMs), [Ag₁₄(S^tBu)₁₀(CF₃COO)₄(bpa)₂]_n (bpa = 1,2-bis(4-pyridyl)acetylene) and [Ag₁₂(S^tBu)₆(CF₃COO)₆(bpeb)₃]_n (bpeb = 1,4-bis(pyridin-4-ylethynyl)benzene) composed of Ag₁₄ and Ag₁₂ chalcogenolate cluster cores, respectively, bridged by acetylenic bispyridine linkers. The linker structures and electrostatic interaction between positively charged SCAMs and negatively charged DNA confer the SCAMs with the ability to suppress the high background fluorescence of single-stranded (ss) DNA probes with SYBR Green I nucleic acid stain, leading to high signal-to-noise ratio for label-free target DNA detection.

N-Heterocyclic Thione-Protected Ag4 Tetrahedra and Ag8 Cubes Cocrystallized in a Single Crystal

Polynuclear silver clusters have attracted intensive attention in the academic community owing to their rich physicochemical properties. The development of thione-protected silver clusters has been lagging behind the well-explored thiolate-protected silver-sulfide clusters. Herein, we report two N-heterocyclic thione-protected silver clusters: [Ag₄(2-TBI)₆(SO₄)₃]^2- (Ag₄) and [Br@Ag₈(2-TBI)₁₂(SO₄)₂]³⁺ (Ag₈) (2-TBI = 2-thiobenzimidazol), which cocrystallize to form cluster-based molecular crystals with a CaF₂-type structure. The cocrystal shows high thermal stability in air. Notably, the two cluster-based layers are alternately assembled to exhibit a unique k-vector-differential crystallographic arrangement. This work may lay a foundation for synthesis of atomically precise and stable silver clusters using readily available N-heterocyclic thione ligands.

Solvent-Dependent Photophysical Properties of a Semiconducting One-Dimensional Silver Cluster-Assembled Material

Unraveling the total structure of the atom-precise silver cluster-assembled materials (CAMs) is extremely significant to elucidating the structure-property correlation, but it is a very challenging task. Herein, a new silver CAM is synthesized by a facile synthetic pathway with a unique distorted elongated square-bipyramid-based Ag₁₁ core geometry. The core is protected by two different kinds of the surface protecting ligands (adamantanethiolate and trifluoroacetate) and connected through a bidentate organic linker. The crystallographic data show that this material embraces a one-dimensional periodic structure that orchestrates by various noncovalent interactions to build a thermally stable supramolecular assembly. Further characterization confirms its n-type semiconducting property with an optical band gap of 1.98 eV. The impact of an adamantanethiol-protected silver core on the optical properties of this type of periodic framework is analyzed by the UV-vis absorbance and emission phenomena. Theoretical calculations predicted that the occupied states are majorly contributed by Ag-S. Solvent-dependent photoluminescence studies proved that a polar solvent can significantly perturb the metal thiolate and thiolate-centered frontier molecular orbitals that are involved in the electronic transitions.

Self-assembly of thiolate-protected silver coordination polymers regulated by POMs

Two polyoxometalate (POM)-based thiolate-protected silver coordination polymers were obtained using different Lindquist-type POM precursors under the same conditions. [Ag10(StBu)6(CH3CN)8(Mo6O19)2·2CH3CN]n (abbreviated as Ag10-Mo6) was observed to feature chain-like structures containing Ag10 clusters linked by [Mo6O19]2- anions through Ag-O bonds and to exhibit unprecedented green photoluminescence at room temperature. Interestingly, [Ag18(StBu)12(CH3CN)5(Mo6O19)2·Mo6O19·2CH3CN]n (abbreviated as Ag18-Mo6) was found to contain 20-membered cycle-Ag10S10 each with a diameter of approximately 11.382 Å and constructed from alternating silver and sulfur atoms and interconnected into an elegant Ag-S sheet by interstitial the Ag3StBu and AgCH3CN motifs, and to also contain [Mo6O19]2- counter ions filling in the spaces made by the cycle-Ag10S10 and strengthening the structure by forming Ag-O bonds. Such a stacking structure for thiolate-protected silver compounds has not been previously reported.