It remains a significant challenge to develop a catalyst that merges the advantages of homogeneous and heterogeneous catalysis with high reactivity and great recyclability.Herein,an atomically precise Cu_(6)-NH_(2) na...It remains a significant challenge to develop a catalyst that merges the advantages of homogeneous and heterogeneous catalysis with high reactivity and great recyclability.Herein,an atomically precise Cu_(6)-NH_(2) nanocluster with distorted octahedral Cu_(6) core and NH_(2)-functionalized ligands has been developed as the first homo/heterogeneous catalyst to catalyze the cyclization reaction of propargylic amines with carbon dioxide(CO_(2))under mild conditions.As a homogeneous catalyst,Cu_(6)-NH_(2) shows excellent catalytic activity with high turnover frequency due to highly accessible active sites.The definite coordination geometry and homogeneity nature of active centers make it convenient to investigate the structure–activity relationship at the atomic level through experiments and theory calculations.In addition,the nanocluster exhibits excellent stability,great recrystallizability,and reusability in five catalytic cycles,in which its catalytic performance has no obvious decrease.Moreover,Cu_(6)-NH_(2) incorporates Lewis acid and base sites in metal and ligand,respectively,which can promote catalytic efficiency in a synergistic effect in the absence of any cocatalysts.Importantly,Cu_(6)-NH_(2) can realize direct conversion of CO_(2) in simulated flue gas into oxazolidinones with high efficiency.The metal-ligand cooperative effect and integrated advantages of homogeneous and heterogeneous catalysis would provide new perspectives to achieve advanced metal nanocluster catalysts for CO_(2) conversion.展开更多
Metal nanoclusters possess excellent electrochemical,optical,and catalytic properties,but correlating these properties remains challenging,which is the foundation to generate electrochemiluminescence(ECL).Herein,we re...Metal nanoclusters possess excellent electrochemical,optical,and catalytic properties,but correlating these properties remains challenging,which is the foundation to generate electrochemiluminescence(ECL).Herein,we report for the first time that a structurally determined Pt1Ag18 nanocluster generates intense ECL and simultaneously enhances the ECL of carbon dots(CDs)via an electrocatalytic effect.Pt^(1)Ag_(18)nanocluster show aggregation-induced emission enhancement and aggregation-induced ECL enhancement under light and electrochemical stimulation,respectively.In the presence of tripropylamine(TPrA)as a coreactant,solid Pt1Ag18 shows unprecedented ECL efficiency,which is more than nine times higher than that of 1 mM Ru(bpy)32+with the same TPrA concentration.Potential-resolved ECL spectra reveal two ECL emission bands in the presence of TPrA.The ECL emission centered at 650 nm is assigned to the solid Pt_(1)Ag_(18)nanocluster,consistent with the peak wavelength in self-annihilation ECL and photoluminescence of the solid state.The ECL emission centered at 820 nm is assigned to the CDs on the glassy carbon electrode.The electrocatalytic effect of the nanoclusters enhanced the ECL of the CDs by a factor of more than 180 in comparison to that without nanoclusters.Based on the combined optical and electrochemical results,the ECL generation pathways and mechanisms of Pt1Ag18 and CDs are proposed.These findings are extremely promising for designing multifunctional nanocluster luminophores with strong emissions and developing ratiometric sensing devices.展开更多
Atomically precise water-soluble gold nanoclusters(Au NCs)protected by organic ligands have attracted growing attention in serving as unique nanomaterials with the potential to generate theranostic tools(bioimaging,bi...Atomically precise water-soluble gold nanoclusters(Au NCs)protected by organic ligands have attracted growing attention in serving as unique nanomaterials with the potential to generate theranostic tools(bioimaging,biosensing,and biotherapy),due to their ultrasmall size,superior photoluminescence,good biocompatibility,and nontoxicity.More importantly,Au NCs afford a well-defined atomic packing structure and molecular purity,providing a superior platform to unravel the structure−performance correlations for biodistribution,biological pharmacokinetics,and excretion of Au NCs.In this Review,we mainly survey the synthesis of water-soluble Au NCs and the recent progress in biomedicine of Au NCs,including bioimaging,biosensing,and biotherapy.The effects of ligand and size on the biomedical properties are discussed in detail.We hope that the advances in this research area can expand the applications of Au NCs in biomedicine.展开更多
Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and ato...Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.展开更多
Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to investigate the band structure of AlSb nanoclusters. Large unit cells of 8, 16, 54, 64 and 128 atoms are used to an...Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to investigate the band structure of AlSb nanoclusters. Large unit cells of 8, 16, 54, 64 and 128 atoms are used to analyze the cohesive energy, energy gap, valence bandwidth, and the density of states of the energy levels for AlSb nanoclusters. The results of the present work revealed that the band structure of AlSb nanoclusters differs significantly from that of the bulk AlSb crystal. Also, it is found that the valence band width and the cohesive energy (absolute value) increase as the AlSb crystal size increases, and they tend to stabilize for nanoclusters of more than 50 atoms.展开更多
Developing new templates to evaluate the ligand engineering effect in manipulating nanoclusters from both molecular and supramolecular aspects remains highly desired in cluster science because it allows for an in-dept...Developing new templates to evaluate the ligand engineering effect in manipulating nanoclusters from both molecular and supramolecular aspects remains highly desired in cluster science because it allows for an in-depth understanding of structure-property correlations.We herein presented the secondary ligand(i.e.,the phosphine ligand)engineering based on an Ag_(29) nanocluster template and its dual effects on intracluster structures and intercluster aggregates.The“dissociationcombination equilibrium”of phosphine ligands on the nanocluster surface was controlled by tailoring the C-H…πinteractions within the ligand shell,which led to the fabrication of a family of[Ag_(29)(BDT)_(12)(PR_(3))_(x)]^(3-)nanoclusters.On the molecular level,the dissociation of phosphine ligands contracted the nanocluster framework,while the overall configuration of[Ag_(29)(BDT)_(12)]^(3-)was retained.On the supramolecular level,the complete dissociation of phosphine ligands yielded a bare nanocluster,which followed a chiral crystallization mode,and its crystals displayed high optical activity,derived from circular dichroism and circularly polarized luminescence characterizations.Overall,this work presents the peripheral ligand effects in directionally controlling intracluster configurations and intercluster aggregations,which hopefully benefit future design and preparation of new nanoclusters or cluster-based nanomaterials with customized structures and performances.展开更多
Metal nanoclusters with accurate compositions and precise crystalline structures hold remarkable attention in serving as a unique model catalyst for well-defined correlations between structure and catalytic activity.M...Metal nanoclusters with accurate compositions and precise crystalline structures hold remarkable attention in serving as a unique model catalyst for well-defined correlations between structure and catalytic activity.More importantly,these metal nanoclusters exhibit strong quantum confinement effects,which differ from their larger nanoparticles in a number of catalytic reactions.This review focuses on recent advances of atomically precise metal nanoclusters for C_(1) compound conversion(C_(O),CO_(2),CH_(4),and HCOOH),including thermally-driven catalysis,photocatalysis,and electrocatalysis.The reaction mechanisms are discussed at an atomic-or even electron-level.It is anticipated that the progress in this research area could be extended to catalytic applications of metal nanoclusters in C_(1) chemistry.展开更多
Doping foreign atom(s)in metal nanoclusters is an effective strategy to engineer the properties and functionalities of metal nanoclusters.However,until now,to dope Pd atom into Ag nanoclusters remains a huge challenge...Doping foreign atom(s)in metal nanoclusters is an effective strategy to engineer the properties and functionalities of metal nanoclusters.However,until now,to dope Pd atom into Ag nanoclusters remains a huge challenge.Here we develop a one-step rapid method to synthesize the Pd-doped Ag nanocluster with high yield.The prepared Pd1Ag28 nanocluster was characterized by mass spectroscopy,X-ray photoelectron spectroscopy,X-ray crystallography,fluorescence spectroscopy,ultraviolet-visible absorption spectroscopy and transient absorption spectroscopy.The nanocluster exhibits a perfect face-centered cubic(FCC)kernel structure with a tetrahedron-like shell.Of note,Pd1Ag28 nanocluster had an unexpectedly long excited-state lifetime of 3.3 microseconds,which is the longest excited-state lifetime for Ag-based nanoclusters S0 far.Meanwhile,the excellent near-infrared luminescence indicated the nanocluster has the potential in fluorescent bio-imaging.Besides,it was revealed that Pd1Ag28 nanocluster could be transformed into Au1Ag28 nanocluster via ion exchange reaction of AuPPhzCl with Pd1Ag28 nanocluster.This work provides an efficient synthetic protocol of alloy nanoclusters and wil contribute to study the effect of foreign atom on the properties of metal nanoclusters.展开更多
Available online two new Ni_(8)Mo_(8) bimetallic coordination clusters,[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(PO_(4))](+Solvent)(Ni_(8)PMo_(8),H_(4)TC4A=p-tert-butylthiacalix[4]arene) and[Ni_(4)(TC4A)]_(2)[(Mo_5~V...Available online two new Ni_(8)Mo_(8) bimetallic coordination clusters,[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(PO_(4))](+Solvent)(Ni_(8)PMo_(8),H_(4)TC4A=p-tert-butylthiacalix[4]arene) and[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(OH)(CO_(3))](+Solvent)(Ni_(8)Mo_(8)),were synthesized by solvothermal method and structurally characterized by single-crystal X-ray diffraction,powder X-ray diffraction,FT-IR spectroscopy,and TGA experiments,respectively.The usage of H_(3)PMo_(12)O_(40) as source for Ni_(8)PMo_(8) resulted a sandwich like structure built from two Ni_(4)-thiacalix[4]arene units and a Mo_(8) polyoxometalate with inner spaces of PO_(4)^(3-).Ni_(8)Mo_(8) with the similar structure to that of Ni_(8)PMo_(8) is from H_(2)MoO_(4) starting reagent with OH^(-)and CO_(3)^(2-)anions encapsulated in the center.The two clusters can be directly loaded on carbon paper and utilized as working electrodes which showed distinguishable performances for glucose detection and oxidation.This work provides a better understanding of the structure-property relationships in using substituted polyoxometalates for electrochemical applications and is helpful for building calixarene-based or polyoxometalatebased functional materials.展开更多
Construction of macro-materials with highly oriented microstructures and well-connected interfaces between building blocks is significant for a variety of applications. However, it is still challenging to confine the ...Construction of macro-materials with highly oriented microstructures and well-connected interfaces between building blocks is significant for a variety of applications. However, it is still challenging to confine the desired structures. Thus, well-defined building blocks would be crucial to address this issue. Herein, we present a facile process based on 1.8 nm Pd nanoclusters （NCs） to achieve centimeter-size assemblages with aligned honeycomb structures, where the diameter of a single tubular moiety is -4 μm. Layered and disordered porous assemblages were also obtained by modulating the temperature in this system. The reconciled interactions between the NCs were crucial to the assemblages. As a comparison, 14 nm Pd nanoparticles formed only aggregates. This work highlights the approach of confining the size of the building blocks in order to better control the assembly process and improve the stability of the structures.展开更多
While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique...While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way展开更多
Even though great advances have been achieved in the synthesis of luminescent metal nanoclusters, it is still challenging to develop metal nanoclusters with high quantum efficiency as well as multiple sensing function...Even though great advances have been achieved in the synthesis of luminescent metal nanoclusters, it is still challenging to develop metal nanoclusters with high quantum efficiency as well as multiple sensing functionalities. Here, we demonstrate the rapid preparation of glutathione-capped Au/Ag nanoclusters （GS-Au/Ag NCs） using microwave irradiation and their unique sensing capacities. Compared to bare GS-Au NCs, the doped Au/Ag NCs possess an enhanced quantum yield （7.8% compared to 2.2% for GS-Au NCs）. Several characterization techniques were used to elucidate the atomic composition, particulate character, and electronic structure of the fabricated NCs. According to the X-ray photoelectron spectroscopy （XPS） and X-ray absorption near-edge structure （XANES） spectra, a significant amount of Au exists in the oxidized state as Au（I）, and the Ag atoms are positively charged. In contrast to those nanoclusters that detect only one analyte, the GS-Au/Ag NCs can be used as a versatile sensor for metal ions, anions, and small molecules. In this manner, the NCs can be regarded as a unique sensor-on-a-nanoparticle.展开更多
基金financially supported by the National Natural Science Foundation of China(grant nos.92061201,21825106,21771163,and 22371263)the National Key R&D Program of China(grant no.2021YFA1200301)+1 种基金the Natural Science Foundation of Henan Province(grant no.232300421144)the Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(grant no.234000510007).
文摘It remains a significant challenge to develop a catalyst that merges the advantages of homogeneous and heterogeneous catalysis with high reactivity and great recyclability.Herein,an atomically precise Cu_(6)-NH_(2) nanocluster with distorted octahedral Cu_(6) core and NH_(2)-functionalized ligands has been developed as the first homo/heterogeneous catalyst to catalyze the cyclization reaction of propargylic amines with carbon dioxide(CO_(2))under mild conditions.As a homogeneous catalyst,Cu_(6)-NH_(2) shows excellent catalytic activity with high turnover frequency due to highly accessible active sites.The definite coordination geometry and homogeneity nature of active centers make it convenient to investigate the structure–activity relationship at the atomic level through experiments and theory calculations.In addition,the nanocluster exhibits excellent stability,great recrystallizability,and reusability in five catalytic cycles,in which its catalytic performance has no obvious decrease.Moreover,Cu_(6)-NH_(2) incorporates Lewis acid and base sites in metal and ligand,respectively,which can promote catalytic efficiency in a synergistic effect in the absence of any cocatalysts.Importantly,Cu_(6)-NH_(2) can realize direct conversion of CO_(2) in simulated flue gas into oxazolidinones with high efficiency.The metal-ligand cooperative effect and integrated advantages of homogeneous and heterogeneous catalysis would provide new perspectives to achieve advanced metal nanocluster catalysts for CO_(2) conversion.
基金National Natural Science Foundation of China,Grant/Award Numbers:22004001,21631001,21871001Anhui Provincial Natural Science Foundation,Grant/Award Number:2008085QB84the Ministry of Education,the University Synergy Innovation Program of Anhui Province,Grant/Award Number:GXXT-2020-053。
文摘Metal nanoclusters possess excellent electrochemical,optical,and catalytic properties,but correlating these properties remains challenging,which is the foundation to generate electrochemiluminescence(ECL).Herein,we report for the first time that a structurally determined Pt1Ag18 nanocluster generates intense ECL and simultaneously enhances the ECL of carbon dots(CDs)via an electrocatalytic effect.Pt^(1)Ag_(18)nanocluster show aggregation-induced emission enhancement and aggregation-induced ECL enhancement under light and electrochemical stimulation,respectively.In the presence of tripropylamine(TPrA)as a coreactant,solid Pt1Ag18 shows unprecedented ECL efficiency,which is more than nine times higher than that of 1 mM Ru(bpy)32+with the same TPrA concentration.Potential-resolved ECL spectra reveal two ECL emission bands in the presence of TPrA.The ECL emission centered at 650 nm is assigned to the solid Pt_(1)Ag_(18)nanocluster,consistent with the peak wavelength in self-annihilation ECL and photoluminescence of the solid state.The ECL emission centered at 820 nm is assigned to the CDs on the glassy carbon electrode.The electrocatalytic effect of the nanoclusters enhanced the ECL of the CDs by a factor of more than 180 in comparison to that without nanoclusters.Based on the combined optical and electrochemical results,the ECL generation pathways and mechanisms of Pt1Ag18 and CDs are proposed.These findings are extremely promising for designing multifunctional nanocluster luminophores with strong emissions and developing ratiometric sensing devices.
基金financial support from the Foundation of the Jiangsu Higher Education Institutions of China(22KJB150026)the National Natural Science Foundation of China(22178161,22101128).
文摘Atomically precise water-soluble gold nanoclusters(Au NCs)protected by organic ligands have attracted growing attention in serving as unique nanomaterials with the potential to generate theranostic tools(bioimaging,biosensing,and biotherapy),due to their ultrasmall size,superior photoluminescence,good biocompatibility,and nontoxicity.More importantly,Au NCs afford a well-defined atomic packing structure and molecular purity,providing a superior platform to unravel the structure−performance correlations for biodistribution,biological pharmacokinetics,and excretion of Au NCs.In this Review,we mainly survey the synthesis of water-soluble Au NCs and the recent progress in biomedicine of Au NCs,including bioimaging,biosensing,and biotherapy.The effects of ligand and size on the biomedical properties are discussed in detail.We hope that the advances in this research area can expand the applications of Au NCs in biomedicine.
基金This work is financially supported by the Russian Foundation for Basic Research (No 04-02-9700and 06-02-9600)by the Presidium of the Far Eastern Branch of the Russian Academy of Sciences(No 06-III-A-02-034)
文摘Regimes of continuous and pulsed laser action on high-melting oxide compounds of ZrO2 were found with the aim of obtaining steady coatings on monocrystal silicon on laser ablation.X-ray phase analyses,scanning and atomic-force microscopy reveal that the coatings obtained are of nanocluster structure with the cubic ordering.In this case the nanoclusters reach several hundreds of nanometers in size.An assumption was made that on laser ablation of ZrO2 thermostabilization may take place where a minimum of the surface energy is attained just at cubic ordering.
文摘Ab initio restricted Hartree-Fock method within the framework of large unit cell formalism is used to investigate the band structure of AlSb nanoclusters. Large unit cells of 8, 16, 54, 64 and 128 atoms are used to analyze the cohesive energy, energy gap, valence bandwidth, and the density of states of the energy levels for AlSb nanoclusters. The results of the present work revealed that the band structure of AlSb nanoclusters differs significantly from that of the bulk AlSb crystal. Also, it is found that the valence band width and the cohesive energy (absolute value) increase as the AlSb crystal size increases, and they tend to stabilize for nanoclusters of more than 50 atoms.
文摘Developing new templates to evaluate the ligand engineering effect in manipulating nanoclusters from both molecular and supramolecular aspects remains highly desired in cluster science because it allows for an in-depth understanding of structure-property correlations.We herein presented the secondary ligand(i.e.,the phosphine ligand)engineering based on an Ag_(29) nanocluster template and its dual effects on intracluster structures and intercluster aggregates.The“dissociationcombination equilibrium”of phosphine ligands on the nanocluster surface was controlled by tailoring the C-H…πinteractions within the ligand shell,which led to the fabrication of a family of[Ag_(29)(BDT)_(12)(PR_(3))_(x)]^(3-)nanoclusters.On the molecular level,the dissociation of phosphine ligands contracted the nanocluster framework,while the overall configuration of[Ag_(29)(BDT)_(12)]^(3-)was retained.On the supramolecular level,the complete dissociation of phosphine ligands yielded a bare nanocluster,which followed a chiral crystallization mode,and its crystals displayed high optical activity,derived from circular dichroism and circularly polarized luminescence characterizations.Overall,this work presents the peripheral ligand effects in directionally controlling intracluster configurations and intercluster aggregations,which hopefully benefit future design and preparation of new nanoclusters or cluster-based nanomaterials with customized structures and performances.
基金The authors acknowledge financial supports from the National Key R&D Program of China(no.2018YFE0122600)the National Natural Science Foundation of China(no.21802070).
文摘Metal nanoclusters with accurate compositions and precise crystalline structures hold remarkable attention in serving as a unique model catalyst for well-defined correlations between structure and catalytic activity.More importantly,these metal nanoclusters exhibit strong quantum confinement effects,which differ from their larger nanoparticles in a number of catalytic reactions.This review focuses on recent advances of atomically precise metal nanoclusters for C_(1) compound conversion(C_(O),CO_(2),CH_(4),and HCOOH),including thermally-driven catalysis,photocatalysis,and electrocatalysis.The reaction mechanisms are discussed at an atomic-or even electron-level.It is anticipated that the progress in this research area could be extended to catalytic applications of metal nanoclusters in C_(1) chemistry.
基金We acknowledge the National Natural Science Foundation of China(No.21601178).
文摘Doping foreign atom(s)in metal nanoclusters is an effective strategy to engineer the properties and functionalities of metal nanoclusters.However,until now,to dope Pd atom into Ag nanoclusters remains a huge challenge.Here we develop a one-step rapid method to synthesize the Pd-doped Ag nanocluster with high yield.The prepared Pd1Ag28 nanocluster was characterized by mass spectroscopy,X-ray photoelectron spectroscopy,X-ray crystallography,fluorescence spectroscopy,ultraviolet-visible absorption spectroscopy and transient absorption spectroscopy.The nanocluster exhibits a perfect face-centered cubic(FCC)kernel structure with a tetrahedron-like shell.Of note,Pd1Ag28 nanocluster had an unexpectedly long excited-state lifetime of 3.3 microseconds,which is the longest excited-state lifetime for Ag-based nanoclusters S0 far.Meanwhile,the excellent near-infrared luminescence indicated the nanocluster has the potential in fluorescent bio-imaging.Besides,it was revealed that Pd1Ag28 nanocluster could be transformed into Au1Ag28 nanocluster via ion exchange reaction of AuPPhzCl with Pd1Ag28 nanocluster.This work provides an efficient synthetic protocol of alloy nanoclusters and wil contribute to study the effect of foreign atom on the properties of metal nanoclusters.
基金supported by the National Natural Science Foundation of China(No.91961110)。
文摘Available online two new Ni_(8)Mo_(8) bimetallic coordination clusters,[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(PO_(4))](+Solvent)(Ni_(8)PMo_(8),H_(4)TC4A=p-tert-butylthiacalix[4]arene) and[Ni_(4)(TC4A)]_(2)[(Mo_5~VMo_(3)~ⅥO_(24))(OH)(CO_(3))](+Solvent)(Ni_(8)Mo_(8)),were synthesized by solvothermal method and structurally characterized by single-crystal X-ray diffraction,powder X-ray diffraction,FT-IR spectroscopy,and TGA experiments,respectively.The usage of H_(3)PMo_(12)O_(40) as source for Ni_(8)PMo_(8) resulted a sandwich like structure built from two Ni_(4)-thiacalix[4]arene units and a Mo_(8) polyoxometalate with inner spaces of PO_(4)^(3-).Ni_(8)Mo_(8) with the similar structure to that of Ni_(8)PMo_(8) is from H_(2)MoO_(4) starting reagent with OH^(-)and CO_(3)^(2-)anions encapsulated in the center.The two clusters can be directly loaded on carbon paper and utilized as working electrodes which showed distinguishable performances for glucose detection and oxidation.This work provides a better understanding of the structure-property relationships in using substituted polyoxometalates for electrochemical applications and is helpful for building calixarene-based or polyoxometalatebased functional materials.
文摘Construction of macro-materials with highly oriented microstructures and well-connected interfaces between building blocks is significant for a variety of applications. However, it is still challenging to confine the desired structures. Thus, well-defined building blocks would be crucial to address this issue. Herein, we present a facile process based on 1.8 nm Pd nanoclusters （NCs） to achieve centimeter-size assemblages with aligned honeycomb structures, where the diameter of a single tubular moiety is -4 μm. Layered and disordered porous assemblages were also obtained by modulating the temperature in this system. The reconciled interactions between the NCs were crucial to the assemblages. As a comparison, 14 nm Pd nanoparticles formed only aggregates. This work highlights the approach of confining the size of the building blocks in order to better control the assembly process and improve the stability of the structures.
文摘While thiolate-protected Au nanoclusters （NCs） have drawn considerable interest in various fields, their poor stability in aqueous solution remains a major hurdle for practical applications. Here, we report a unique strategy based on ligand-shell engineering to improve the stability of thiolated Au NCs in solution. By employing two thiol-terminated ligands having oppositely charged functional groups on the surface of the NCs, we demonstrate that the electrostatic attraction between the oppositely charged functional groups of neighboring ligands could amplify the coordination among surface ligands, leading to the formation of pseudo-cage-like structures on the NC surface that could offer higher protection to the Au core in aqueous solution. The strategy developed in this study could be extended to toward practical applications. other metal NCs, further paving the way
基金This work is financially supported by the National Basic Research Program of China （Nos. 2014CB931800 and 2013CB931800）, the National Natural Science Foundation of China （Nos. 21407140, 21431006 and 91227103）, and Scientific Research Grant of Hefei Science Center of CAS （No. 2015SRG-HSC038）. J. Zhang appreciates the Grants from the China Postdoctoral Science Foundation （No. 2013M531515） and the Fun- damental Research Funds for the Central Universities （No. WK2060190036）. The authors also thank beamline BL14W1 （Shanghai Synchrotron Radiation Faculty） for providing the beam time.
文摘Even though great advances have been achieved in the synthesis of luminescent metal nanoclusters, it is still challenging to develop metal nanoclusters with high quantum efficiency as well as multiple sensing functionalities. Here, we demonstrate the rapid preparation of glutathione-capped Au/Ag nanoclusters （GS-Au/Ag NCs） using microwave irradiation and their unique sensing capacities. Compared to bare GS-Au NCs, the doped Au/Ag NCs possess an enhanced quantum yield （7.8% compared to 2.2% for GS-Au NCs）. Several characterization techniques were used to elucidate the atomic composition, particulate character, and electronic structure of the fabricated NCs. According to the X-ray photoelectron spectroscopy （XPS） and X-ray absorption near-edge structure （XANES） spectra, a significant amount of Au exists in the oxidized state as Au（I）, and the Ag atoms are positively charged. In contrast to those nanoclusters that detect only one analyte, the GS-Au/Ag NCs can be used as a versatile sensor for metal ions, anions, and small molecules. In this manner, the NCs can be regarded as a unique sensor-on-a-nanoparticle.
