Synthesis Of Nanoclusters Research Articles

Synthesis of Photoluminescent 2D Self-Assembled Silver Thiolate Nanoclusters for Sensors and Biomolecule Support.

Silver thiolate nanoclusters (Ag NCs) show distinctive optical properties resulting from their hybrid nature, metallic and molecular, exhibiting size-, structure-, and surface-dependent photoluminescence, thus enabling the exploitation of Ag NCs for potential applications in nanobiotechnology, catalysis, and biomedicine. However, tailoring Ag NCs for specific applications requires achieving long-term stability and may involve modifying surface chemistry, fine-tuning ligand composition, or adding functional groups. In this study, we report the synthesis of novel Ag NCs using 2-ethanephenylthiolate (SR) as a ligand, highlight critical points addressing stability, and characterize their optical and structural properties. A preliminary electrical characterization revealed high anisotropy, well suited for potential use in electronics/sensing applications. We also present the synthesis and characterization of Ag NCs using 10-carboxylic 2-ol thiolate (SR'COOH) having a terminal carboxylic group for conjugation with amine-containing molecules. We present a preliminary assessment of its bioconjugation capability using bovine serum albumin as a model protein indicating its prospective application as a biomolecule support.

Gold Nanoclusters Synthesized within Single-Chain Nanoparticles as Catalytic Nanoreactors in Water.

Metalloenzymes are able to catalyze complex biochemical reactions in cellular (aqueous) media with high efficiency. In recent years, a variety of metal-containing single-chain nanoparticles (SCNPs) have been synthesized as simplified metalloenzyme-mimetic nano-objects. However, most of the metal-containing SCNPs reported so far contained complexed metal ions but not metal nanoclusters (NCs) with diameter <5 nm, which could be used as powerful, emerging catalysts. Herein, we report the synthesis of gold nanoclusters (Au-NCs) within SCNPs and the further use of Au-NCs/SCNPs as catalytic nanoreactors in water. We demonstrate that a common motif contained in several drugs (i.e., the aminophenyl-oxazolidinone fragment present in Rivaroxaban, Sutezolid, and Linezolid) can be efficiently prepared in water from a hydrophobic precursor compound by using the Au-NCs/SCNPs as efficient catalytic nanoreactors. In summary, this work paves the way forthe synthesis of metal-NCs/SCNPs for advanced catalysis in aqueous media.

Atomically Dispersed Gold Nanoclusters and Single Atoms Coexisting Chiral Electrode for High‐Performance Enantioselective Electrosynthesis using H2o as Hydrogen Source

AbstractDeveloping chiral electrode catalysts for enantioselective electrosynthesis is a great challenge, as it requires catalysts that possess both high activity and enantioselectivity. Precise synthesis of nanoclusters and single atoms coexisting chiral catalysts provide a promising pathway for enhancing asymmetric catalytic performance. Herein, chiral electrode catalysts are fabricated comprising gold clusters (R‐AuC) and single atoms (R‐AuS) on graphene oxide (R‐AuC/S@GO) through an assembly‐irradiation strategy. Thereinto, the R‐Aus is in situ generated from R‐AuC under light irradiation. The monoatomization process can be precisely regulated by changing the wavelength of the light, resulting in four Au‐based chiral electrode (R‐Au@GO) catalysts with different ratios of nanoclusters and single atoms. These chiral electrodes are applied in the electrocatalytic enantioselective hydrogenation of methyl benzoylformate (MB) to chiral methyl mandelate (S‐MM), and the R‐AuC/S‐2@GO with ≈26% R‐AuC and 74% R‐AuS achieve the highest catalytic activity (35 µmol cm−2 h−1 productivity) and enantioselectivity [97% enantiomeric excess (ee)]. Detailed experimental analysis and density functional theory calculations reveal that the R‐AuS on GO promotes the in situ generation of H* species, and R‐AuC mainly drives the enantioselective conversion of MB by transferring the H* species to the carbonyl group of MB, ultimately yielding chiral S‐MM.

Advances in the synthesis of gold nanoclusters (AuNCs) of proteins extracted from nature

Abstract Over the past few decades, nanotechnology has developed rapidly and has been applied to various fields. Gold nanoclusters (AuNCs), which are composed of several hundred atoms, are a new type of nanomaterial. AuNCs are often synthesized using ligands or templates. The interaction between the gold atoms and the groups of the ligands or templates results in unexpected physical and chemical properties. In recent studies, natural proteins have often been used as templates to synthesize AuNCs. The unique structure of natural proteins endows AuNCs with biological functions, such as biocompatibility and enzymatic activity. The unique properties of these natural protein-AuNCs have been verified and applied in various fields. In this article, the synthetic strategies used to produce AuNCs have been divided into two categories: animal-derived and plant-derived protein synthesis. The protein types and synthesis strategies used in the current mainstream research are reviewed, and their applications in detection and biological imaging are summarized. Finally, the problems and future development directions of AuNCs synthesized from natural proteins are discussed, laying a foundation for the biological application of protein-AuNCs.

The synthesis of fluorescent nanoclusters based on the etching reaction

The synthesis of fluorescent nanoclusters based on the etching reaction

Synthesis of Ni nanoclusters supported on diamond by plasma technique and their electrochemical properties

In this study, particles of synthetic undoped diamond (DN) obtained via the high pressure – high temperature method were coated with a nickel shell using metallic nickel plasma in a two-jet plasma generator with gas vortex and magnetic flux stabilization. Through the use of scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, we observed the formation of a nickel diamond composite with a core-shell structure, where DN serves as the core and Ni nanoclusters form the shell (DN@Ni). The results of voltammetric analysis indicated that DN@Ni, when deposited on a graphite electrode, exhibited significant electrocatalytic activity in the oxidation of methanol and paracetamol in an alkaline electrolyte.

Photochemical eco-friendly synthesis of photothermal and emissive copper nanoclusters in water: towards sustainable nanomaterials

We performed a sustainable and environmentally benign synthesis of stable Cu nanoclusters in water by UV irradiation of a CuII complex.

Solid-state synthesis of ligand-assisted lead halide nanoclusters.

A solid-state synthesis of blue-emitting lead halide nanoclusters has been demonstrated for the first time. The solid-state grinding synthesis provides a facile method to produce highly confined lead bromide clusters under ambient conditions. Both CH3NH3PbBr3 perovskite magic-sized clusters and lead halide molecular clusters have been produced, as confirmed by comparison to those synthesized using a ligand-assisted reprecipitation method in terms of electronic absorption, photoluminescence, and solid state characterization.

Exploring the impact of various reducing agents on Cu nanocluster synthesis.

The synthesis of copper (Cu) nanoclusters (NCs) has experienced significant advancements in recent years. Despite the exploration of metal NCs dating back almost two decades, challenges specific to Cu NC synthesis arise from the variable oxidation states and heightened reactivity of intermediate Cu complexes, distinguishing it from its analogous counterparts. In this study, we present a comprehensive overview of this newly evolving research domain, focusing on the synthetic aspects. We delve into various factors influencing the synthesis of Cu NCs, with specific emphasis on the role of reducing agents. The impact of the reducing agent is particularly pivotal in this synthetic process, ultimately influencing the formation of model M(0)-containing NCs, which are less readily accessible in the context of Cu NCs. We anticipate that this frontier article will pave the way for accelerated research in the field of Cu NCs. By aiding in the selection of specific reaction conditions and reducing agents, we believe that this work will contribute to a faster-paced exploration of Cu NCs, further advancing our understanding and applications in this exciting area of nanomaterial research.

The roles of templates consisting of amino acids in the synthesis and application of gold nanoclusters.

Gold nanoclusters (AuNCs) with low toxicity, high photostability, and facile synthesis have attracted great attention. The ligand is of great significance in stabilizing AuNCs and regulating their properties. Ligands consisting of amino acids (proteins and peptides) are an ideal template for synthesizing applicative AuNCs due to their inherent bioactivity, biocompatibility, and accessibility. In this review, we summarize the correlation of the template consisting of amino acids with the properties of AuNCs by analyzing different peptide sequences. The selection of amino acids can regulate the fluorescence excitation/emission and intensity, size, cell uptake, and light absorption. By analyzing the role played by AuNCs stabilized by proteins and peptides in the application, universal rules and detailed performances of sensors, antibacterial agents, therapeutic reagents, and light absorbers are reviewed. This review can guide the template design and application of AuNCs when selecting proteins and peptides as ligands.

Synthesis of Bimetallic Gold-Silver Nanoclusters and Its Application as Pb (II) Sensing Based on Fluorescence Technique

Much research has been done on gold nanoclusters stabilized by biomolecules because of their remarkable fluorescence properties and potential biological applications. Here, we synthesize bimetallic gold-silver nanoclusters in a protein template using Galvanic Exchange (GE) Method. The samples were analyzed using UV-visible spectroscopy, a fluorolog (fluorescence spectrometer), and a lifetime kit using Time-Correlated Single-Photon Counting method. It is found that the bimetallic gold-silver nanoclusters emit bright red fluorescence with a long fluorescence lifetime in the range of microseconds. The bimetallic gold nanoclusters were used for Pb (II) detection using fluorescence technique. The fluorescence intensity of nanoclusters increased as the concentration of added Pb (II) increased. This work suggests that bimetallic gold-silver nanoclusters can be used for Pb detection with a detection limit of 15 nmol/L and this sensing will contribute to providing clean water without Pb contamination.

DNA-templated fluorescent metal nanoclusters and their illuminating applications.

After the discovery of DNA during the mid-20th century, a multitude of novel methodologies have surfaced which exploit DNA for its various properties. One such recently developed application of DNA is as a template in metal nanocluster formation. In the early years of the new millennium, a group of researchers found that DNA can be adopted as a template for the binding of metal nanoparticles that ultimately form nanoclusters. Three metal nanoclusters have been studied so far, including silver, gold, and copper, which have a plethora of biological applications. This review focuses on the synthesis, mechanisms, and novel applications of DNA-templated metal nanoclusters, including the therapies that have employed them for their wide range of fluorescent properties, and the future perspectives related to their development by exploiting machine learning algorithms and molecular dynamics simulation studies.

Synthesis of fluorescent gold nanoclusters in the presence of adenosine monophosphate: effect of azide ions

It has been demonstrated that fluorescence of gold nanoclusters formed via HAuCl4 reduction with citrate buffered solution in the presence of adenosine monophosphate can be tuned via addition of NaN3. No fluorescent products have been detected at large excess of NaN3, whereas at intermediate concentrations of NaN3 blue–green fluorescence has been gradually changed to yellow and weakened.

Recent advances in synthesis and properties of silver nanoclusters.

Achieving atomic precision in nanostructured materials is essential for comprehending formation mechanisms and elucidating structure-property relationships. Within the realm of nanoscience and technology, atomically precise ligand-protected noble metal nanoclusters (NCs) have emerged as a rapidly expanding area of interest. These clusters manifest quantum confinement-induced optoelectronic, photophysical, and chemical properties, along with remarkable catalytic capabilities. Among coinage metals, silver distinguishes itself for the fabrication of stable nanoclusters, primarily due to its cost-effectiveness compared to gold. This minireview provides an overview of recent advancements since 2020 in synthetic methodologies and ligand selections toward attaining NCs boasting a minimum of two free valence electrons. Additionally, it explores strategies for fine-tuning optical properties. The discussion extends to surface reactivity, elucidating how exposure to ligands, heat, and light induces transformations in size and structure. Of paramount significance are the applications of silver NCs in catalytic reactions for energy and chemical conversion, supplemented by in-depth mechanistic insights. Furthermore, the review delineates challenges and outlines future directions in the NC field, with an eye toward the design of new functional materials and prospective applications in diverse technologies, including optoelectronics, energy conversion, and fine chemical synthesis.

Rational synthesis of 3D coral-like ZnCo2O4 nanoclusters with abundant oxygen vacancies for high-performance supercapacitors.

Transition metal oxides with high theoretical capacitance are regarded as desired electrode materials for supercapacitors, however, the poor conductivity and sluggish charge transfer kinetics constrain their electrochemical performance. The three-dimensional (3D) coral-like ZnCo2O4 nanomaterials with abundant oxygen vacancies were synthesized through a facile hydrothermal method and chemical reduction approach. The introduced oxygen vacancies can provide more active sites and lower the energy barrier, thereby facilitating the kinetics of surface reactions. Furthermore, the abundant oxygen vacancies in metal oxides can function as shallow donors to facilitate charge carrier diffusion, resulting in a faster ion diffusion rate and superior electrochemical conductivity. The electrochemical performance of ZnCo2O4 was optimized by the introduction of oxygen vacancies. The ZnCo2O4 nanoclusters, reduced by 0.5 M NaBH4 (ZnCo2O4-0.5), exhibit a specific capacitance of 2685.7 F g-1 at 1 A g-1, which is nearly twice that of the pristine ZnCo2O4 (1525.7 F g-1 at 1 A g-1). The ZnCo2O4-0.5 exhibits an excellent rate capacity (81.9% capacitance retention at 10 A g-1) and a long cycling stability (72.6% specific capacitance retention after 10 000 cycles at 3 A g-1). Furthermore, the asymmetric supercapacitor (ASC, ZnCo2O4-0.5 nanoclusters//active carbon) delivers a maximum energy density of 50.2 W h kg-1 at the power density of 493.7 W kg-1 and an excellent cycling stability (75.3% capacitance retention after 3000 cycles at 2 A g-1), surpassing the majority of previously reported ZnCo2O4-based supercapacitors. This work is important for revealing the pivotal role of implementing the defect engineering regulation strategy in achieving optimization of both electrochemical activity and conductivity.

Substituent effect in determining the total structure of an all-alkynyl-protected Ag98 nanocluster for methanol tolerant oxygen reduction reaction.

Metal nanoclusters (NCs) with atomically precise structures are desirable models for truly understanding their structure-property relationship. This study reports the synthesis and structural anatomy of a Ag98 NC protected solely by an alkynyl ligand, 2-(trifluoromethyl)phenylacetylene (2-CF3PhC[triple bond, length as m-dash]CH), which features a -CF3 substituent at the ortho position (ortho-CF3). 2-CF3PhC[triple bond, length as m-dash]CH ligands are so exquisitely arranged on the surface of Ag98 that the steric hindrance caused by ortho-CF3 is minimized but its function as a hydrogen-bond (H-bond) acceptor (H⋯F) is maximized. Such a rule also applies to inter-cluster interactions which define the stacking sequence of Ag98 NCs. When supported on carbon black, Ag98 NCs demonstrate desirable oxygen reduction activity with robust long-term durability and excellent methanol tolerance, outperforming the commercial Pt/C catalyst.

Cascaded recycling amplification mediated in situ synthesis of silver nanoclusters for the construction of sensitive and label-free electrochemical sensor

A growing number of studies have shown the crucial role of microRNA (miRNA) sensing in cancer clinical diagnosis and prognosis research. In this study, a label-free and enzyme-free electrochemical sensor was presented to achieve sensitive determination of miRNA 122, which was constructed based on in situ synthesis of silver nanoclusters (AgNCs) mediated by cascaded recycling amplification. The efficient and cascaded recycling amplification was initiated by the target miRNA 122, resulting in the release of signal probe with rich cytosine bases, which would be loaded on the sensing interface for in situ synthesis of silver nanoclusters, leading to dramatically increased current for quantitative analysis. This method achieved selective and robust miRNA 122 sensing in human serum samples with a detection limit down to 27 aM. The proposed work would provide an innovative method for determining different biomarkers, holding great potential for boosting the development of clinical diagnosis and drug investigation.

Highly dispersed ultrasmall BiOCl nanoclusters on graphene sheets as high-performance anion-capture electrode for hybrid capacitive deionization

BiOCl nanomaterials, because of their unique layered structure and fascinating physicochemical properties, have attracted enormous attention as anode material for capacitive deionization (CDI) towards the relief of global freshwater scarcity. However, the synthesis of ultrasmall BiOCl nanoclusters remains a considerable challenge, while the effect of crystalline surfaces on the Cl− ion intercalation/deintercalation has not yet been explored so far. In this work, highly dispersed BiOCl nanoclusters with the predominant exposure of (110) and (101) planes on graphene sheets (BiOCl@G) are fabricated by nanoconfinement and air-plasma strategy. On one hand, the ultrasmall BiOCl nanoclusters with size of ∼3 nm significantly increased their atomic utilization and electrochemical active sites, whereas the preferred crystalline planes of (110) and (101) favored the Cl− intercalation/deintercalation process within BiOCl. On the other hand, the dominant mesopores, along with a large interlayer distance (∼0.4 nm) between exfoliated graphene sheets, ensured the fast ion transport-adsorption at BiOCl/solution interface. With these novel structural features, the BiOCl@G possesses excellent figure-of-merits in terms of the Cl−-adsorption capacity (109.8 mg g−1), adsorption rate (0.110 mg g−1 s−1), energy consumption, and CDI cycling stability. These results provide new fundamental insights for developing high performance BiOCl-graphene nanocomposites used in CDI desalination and beyond.

Self-assembled programmable DNA nanoflower for in situ synthesis of gold nanoclusters and integration with Mn-MOF to sensitively detect AFB1

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that is susceptible to contamination of agricultural products and can cause chronic effects on humans. Thus, the establishment of highly sensitive and efficient AFB1 detection method is crucial to ensure food safety and human health. Here, we developed programmable DNA nanoflowers (DNF) with dual functionality for in situ synthesis of gold nanoclusters (AuNCs) and DNA recognition. The AuNCs synthesized using DNF as template (DNF@AuNCs) possessed good fluorescence properties and stability, and were applied as stable signal probes for constructing sensitive aptasensor. DNF completed the transition from bud to blooming flower, shifting its morphology from 3D to 2D structure during the in-situ synthesis of AuNCs, leading to the exposure of more template sequences. The designed hairpins DNA were subsequently used for local catalytic hairpin assembly (LCHA) on the surface of Mn-MOF. A substantial number of amplified products H2-H3 was obtained by conformational conversion, which was complementary to the sequence of DNF. Upon hybridization of H2-H3 with DNF@AuNCs, the fluorescence of AuNCs is quenched by adjacent guanine-rich (G-rich) base at the 3′ end of H3. The switch of LCHA is controlled by the conformational change of H1 which contains the AFB1 aptamer sequence, thus enabling precise detection of AFB1. The DNF@AuNCs and Mn-MOF-based fluorescence aptasensor achieved a detection limit of 7 pg/mL for AFB1, with a detection range of 0.01–200 ng/mL. The aptasensor also exhibits high selectivity, reproducibility, and stability, making it prospective for food safety monitoring.

Synthesis of silver nanoclusters using a double-stranded DNA template and its application for captopril detection

The purpose of this study was to explore the feasibility and mechanism of synthesizing silver nanoclusters (AgNCs) using a double-stranded DNA (dsDNA) template and to use the AgNCs as probes for captopril detection. The results showed that the binding of silver ions towards DNA bases deduced the destruction of the initial dsDNA structure, and AgNCs with decent quantum yield (43.54%) were obtained. The detection using these AgNCs probes showed good performance for captopril, with a linear range of 0.1–0.8 μg·mL−1 and a detection limit of 0.045 μg·mL−1. Recovery results in real samples of Apocynum venetum leaf tea and Ginkgo biloba leaf tablet demonstrated its good applicability. This work not only extended the understanding of DNA-AgNCs but also provided a fast and cost-effective tool for captopril detection.