Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, i...Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, is energetically preferred. The adsorption energies of HCN on the silver clusters reach a local maximum at n = 4, which is only about 0.450 eV, indicating that the adsorbed HCN molecule is weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.展开更多
The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms...The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms in AgnO- （n--1-8） are inert in the interactions with H2 or D2 at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation （PROX） of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between AgnO- （n=1-8） and H2 were explored using DFT calculations. The results indicated that adsorption of H2 on any site of AgnO- （n=1-8） is extremely weak, and oxidation of H2 by any kind of oxygen in AgnO- （n=1-8） has an apparent barrier strongly dependent on the adsorption style of the ＂O＂. These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.展开更多
At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and el...At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and electronic properties of the small silver clusters （Agn, n ≤ 7）. The results presented in this study are in good agreement with the experimental data and theoretical values obtained at a higher level of theory from the literature. Static polarizability and hyperpolarizability are also reported. It is verified that the mean dipole polarizability per atom exhibits an odd-even oscillation and that the polarizability anisotropy is directly related to the cluster shape. In this article, the first study of hyperpolarizabilities of small silver clusters is presented. Except for the monomer, the second hyperpolarizabilities of the silver clusters are significantly larger than those of the copper clusters.展开更多
The development of stimuli-responsive circularly polarized luminescence(CPL)materials is quite attractive but challenging.Here,a pair of atomically precise enan-tiomers R/S-Ag20 nanoclusters has been synthesized using...The development of stimuli-responsive circularly polarized luminescence(CPL)materials is quite attractive but challenging.Here,a pair of atomically precise enan-tiomers R/S-Ag20 nanoclusters has been synthesized using chiral acid ligands.And then,stimuli-responsive CPL materials were developed by assembling the chiral silver nanoclusters with an achiral bridging ligand.The atomically precise silver cluster-assembled materials produce CPL with a dissymmetry factor(|glum|)of 1×10-3,through the high-efficiency chiral induction process.More interestingly,the single CPL band at room temperature could quickly transform into highly separated dual CPL emissions at low temperature.This study provides a new strategy for the rational functionalization of chiral silver clusters in preparing cluster-based CPL emitters and enriches the types of stimuli-responsive CPL materials.展开更多
In this work,three stable dumbbell-shaped silver clusters 1~3,formed by a novel bifunctional ligand Ph2P-C6H4-3-C=CH,are presented.All three complexes have cage structures constructed with thirty-six silver atoms,whic...In this work,three stable dumbbell-shaped silver clusters 1~3,formed by a novel bifunctional ligand Ph2P-C6H4-3-C=CH,are presented.All three complexes have cage structures constructed with thirty-six silver atoms,which are templated by chloride anions.During the self-assembly process of silver acetylides,argentophilic interactions and Ag(I)-ethynide interactions are important for the formation of silver cores to yield a diversity of silver clusters.Weak molecular interactions(π-π,C-H…π,C-H…F,C-H…O)are also found in these complexes,which are crucial to stabilizing these silver clusters.Compared with simple alkynyl ligands(RC≡C-),the introduction of phosphine groups into alkynyl ligand can effectively control the undesired infinite growth of silver acetylides.The photophysical behaviors of complexes 1~3 are studied,showing intense orange roomtemperature luminescence in the solid state upon the exposure to UV light.The luminescence mainly arises from ligand-to-metal charge transfer(LMCT)and metal-cluster-centered transitions(MC)within the silver clusters.展开更多
New types of fluorescence DNA-based silver nanoclusters（DNAn-Ag NCs, n = 1, 2, 3c, 4c, 5c） were synthesized by C3T-rich nucleotides as templates. It is found that the assembly of DNAn-Ag NCs with nucleotides contain...New types of fluorescence DNA-based silver nanoclusters（DNAn-Ag NCs, n = 1, 2, 3c, 4c, 5c） were synthesized by C3T-rich nucleotides as templates. It is found that the assembly of DNAn-Ag NCs with nucleotides containing GAG sequences produce silver clusters with an enhanced red emission. Results indicate that GAG is the good enhancer of DNAn-Ag NCs constructed by C3T-rich nucleotides. The fluorescence titration reveals that enhanced red emission is sensitive to Fe（Ⅲ/Ⅱ） ions with the formation of non-emission nanoclusters. Thus, the GAG-containing nucleotide can be an enhancer for the emission of silver clusters with C3T-rich nucleotide and a mediator of the iron-cluster interplay.展开更多
A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence ...A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence spectrum. The title compound crystallizes in triclinic, space group P with a = 11.611（3）, b = 15.610（5）, c = 15.624（7） , α = 113.942（6）, β = 104.520（6）, γ = 104.230（4）°, V = 2304.1（14） 3, C60H77Ag6N22O4.5S6, Mr = 2018.02, Dc = 1.454 g/cm3, μ（MoKα） = 1.435 mm-1, F（000） = 1005, Z = 1, the final R = 0.0468 and wR = 0.1474 for 6608 observed reflections （I 2σ（I））. In the structure, the S atom of the ligand L2 （L2 = benzaldehyde thiosemicarbazone） served as a triply bridged chelator to connect the six silver atoms into a Ag6L26 cluster. The luminescence property of compound 2 was investigated at room temperature.展开更多
A tetrahedral silver(I) cluster complex {Ag4[HC(PPh2)3](S2PPh2)3}ClO4(1,HC(PPh2)3 = 1,1,1-tris(triphenylphosphino)methane, S2PPh2 = diphenyldithiophosphinate) was synthesized by assembling silver ion with phosphor and...A tetrahedral silver(I) cluster complex {Ag4[HC(PPh2)3](S2PPh2)3}ClO4(1,HC(PPh2)3 = 1,1,1-tris(triphenylphosphino)methane, S2PPh2 = diphenyldithiophosphinate) was synthesized by assembling silver ion with phosphor and sulphur mixed-ligand system. The complex was characterized by single-crystal X-ray crystallography, high-resolution mass spectroscopy and thermal analysis. In the crystal structure, an inverted tetrahedron was constructed from Ag4 metal skeleton. The Ag4 cage was stabilized by three diphenyldithiophosphinate ligands and one 1,1,1-tris(triphenylphosphino)methane ligand. 1 exhibits luminescent properties in solid state. A bright yellow-green emission centered at 533 nm has been observed in solid state. Large Stokes' shifts with long range of emissive lifetime indicate that the emission likely originates from a triplet state parentage.展开更多
A new 1D silver cluster-assembled complex Ag_(10)bpy-CH_3CN exhibiting intense photoluminescence was reported. Upon the loss of coordinated acetonitrile, Ag_(10)bpy-CH_3CN form Ag_(10)bpy with Ag_(10)S_6 cores slightl...A new 1D silver cluster-assembled complex Ag_(10)bpy-CH_3CN exhibiting intense photoluminescence was reported. Upon the loss of coordinated acetonitrile, Ag_(10)bpy-CH_3CN form Ag_(10)bpy with Ag_(10)S_6 cores slightly distorted, being accompanied with photoluminescence quenching. Inverse process can be realized by treating Ag_(10)bpy with acetonitrile and shows a selectively erasable photoluminescent switch.展开更多
Resistive switching Ag/Ag2S nanoclusters were formed by sulphidation of melting-dispersed thin and continuous Ag films. The morphology, structure and electrical properties of the prepared clusters were characterized b...Resistive switching Ag/Ag2S nanoclusters were formed by sulphidation of melting-dispersed thin and continuous Ag films. The morphology, structure and electrical properties of the prepared clusters were characterized by scanning (SEM), transmitting electron (TEM), scanning resistance microscopes (SRM) and Raman scattering. Hysteretic resistive switching behavior was observed in the samples that were studied with ON/OFF switching voltage equal to 8 - 10 V respectively. Simple empirical numerical simulation model, based on Deal-Grove model assumptions and mechanisms, for silver nanoclusters sulphidation process, was proposed.展开更多
基金supported by the National Natural Science Foundation of China(21203027,21073035,21373048)Funds of Fujian Province(2012J01032,2012J01041)Fuzhou University(2012-XQ-11)
文摘Density functional theory calculations have been performed to study the interaction of small silver clusters, Ag2-Ag9, with HCN. The adsorption of HCN on-top site of the silver cluster, among various possible sites, is energetically preferred. The adsorption energies of HCN on the silver clusters reach a local maximum at n = 4, which is only about 0.450 eV, indicating that the adsorbed HCN molecule is weakly perturbed. The adsorbed C-N and C-H stretching frequencies are blue- and red-shifted compared with the values of free HCN, respectively.
文摘The interactions between AgnO- （n=1-8） and H2 （or D2） were explored by combination of the mass spectroscopy experiments and density function theory （DFT） calculations. The experiments found that all oxygen atoms in AgnO- （n--1-8） are inert in the interactions with H2 or D2 at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation （PROX） of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between AgnO- （n=1-8） and H2 were explored using DFT calculations. The results indicated that adsorption of H2 on any site of AgnO- （n=1-8） is extremely weak, and oxidation of H2 by any kind of oxygen in AgnO- （n=1-8） has an apparent barrier strongly dependent on the adsorption style of the ＂O＂. These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.
基金Project supported by CNPq,CAPES,and FAPES(Brazilian Agencies)
文摘At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and electronic properties of the small silver clusters （Agn, n ≤ 7）. The results presented in this study are in good agreement with the experimental data and theoretical values obtained at a higher level of theory from the literature. Static polarizability and hyperpolarizability are also reported. It is verified that the mean dipole polarizability per atom exhibits an odd-even oscillation and that the polarizability anisotropy is directly related to the cluster shape. In this article, the first study of hyperpolarizabilities of small silver clusters is presented. Except for the monomer, the second hyperpolarizabilities of the silver clusters are significantly larger than those of the copper clusters.
基金National Natural Science Foundation of China,Grant/Award Number:92061201 U21A20277Thousand Talents(Zhongyuan Scholars)Program of Henan Province,Grant/Award Number:234000510007Excellent Youth Foundation of Henan Scientific Committee,Grant/Award Number:232300421022。
文摘The development of stimuli-responsive circularly polarized luminescence(CPL)materials is quite attractive but challenging.Here,a pair of atomically precise enan-tiomers R/S-Ag20 nanoclusters has been synthesized using chiral acid ligands.And then,stimuli-responsive CPL materials were developed by assembling the chiral silver nanoclusters with an achiral bridging ligand.The atomically precise silver cluster-assembled materials produce CPL with a dissymmetry factor(|glum|)of 1×10-3,through the high-efficiency chiral induction process.More interestingly,the single CPL band at room temperature could quickly transform into highly separated dual CPL emissions at low temperature.This study provides a new strategy for the rational functionalization of chiral silver clusters in preparing cluster-based CPL emitters and enriches the types of stimuli-responsive CPL materials.
基金the“Thousand Talents Program”of Chinathe National Natural Science Foundation of China(No.21101170 and 21573139)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Shaanxi Normal University。
文摘In this work,three stable dumbbell-shaped silver clusters 1~3,formed by a novel bifunctional ligand Ph2P-C6H4-3-C=CH,are presented.All three complexes have cage structures constructed with thirty-six silver atoms,which are templated by chloride anions.During the self-assembly process of silver acetylides,argentophilic interactions and Ag(I)-ethynide interactions are important for the formation of silver cores to yield a diversity of silver clusters.Weak molecular interactions(π-π,C-H…π,C-H…F,C-H…O)are also found in these complexes,which are crucial to stabilizing these silver clusters.Compared with simple alkynyl ligands(RC≡C-),the introduction of phosphine groups into alkynyl ligand can effectively control the undesired infinite growth of silver acetylides.The photophysical behaviors of complexes 1~3 are studied,showing intense orange roomtemperature luminescence in the solid state upon the exposure to UV light.The luminescence mainly arises from ligand-to-metal charge transfer(LMCT)and metal-cluster-centered transitions(MC)within the silver clusters.
基金Financial support of National Natural Science Foundation of China(No.21271090)Coordination Chemistry State key Laboratory Foundation of Nanjing University
文摘New types of fluorescence DNA-based silver nanoclusters（DNAn-Ag NCs, n = 1, 2, 3c, 4c, 5c） were synthesized by C3T-rich nucleotides as templates. It is found that the assembly of DNAn-Ag NCs with nucleotides containing GAG sequences produce silver clusters with an enhanced red emission. Results indicate that GAG is the good enhancer of DNAn-Ag NCs constructed by C3T-rich nucleotides. The fluorescence titration reveals that enhanced red emission is sensitive to Fe（Ⅲ/Ⅱ） ions with the formation of non-emission nanoclusters. Thus, the GAG-containing nucleotide can be an enhancer for the emission of silver clusters with C3T-rich nucleotide and a mediator of the iron-cluster interplay.
基金supported by the Postdoctoral Science Foundation of Central South University
文摘A new hexanuclear silver （I） compound 2 containing thiosemicarbazone with the group of benzene was synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis and fluorescence spectrum. The title compound crystallizes in triclinic, space group P with a = 11.611（3）, b = 15.610（5）, c = 15.624（7） , α = 113.942（6）, β = 104.520（6）, γ = 104.230（4）°, V = 2304.1（14） 3, C60H77Ag6N22O4.5S6, Mr = 2018.02, Dc = 1.454 g/cm3, μ（MoKα） = 1.435 mm-1, F（000） = 1005, Z = 1, the final R = 0.0468 and wR = 0.1474 for 6608 observed reflections （I 2σ（I））. In the structure, the S atom of the ligand L2 （L2 = benzaldehyde thiosemicarbazone） served as a triply bridged chelator to connect the six silver atoms into a Ag6L26 cluster. The luminescence property of compound 2 was investigated at room temperature.
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJQN201801602,KJQN201801607)the Basic and Frontier Research Project of Chongqing Science and Technology Commission(No.cstc2018jcyjAX0110)+1 种基金the Key Laboratory for Green Chemical Technology of Chongqing University of Education(No.2016xjpt08)the Research Project of Chongqing University of Education(Nos.JG2017015,KY20180241,YX-2019-01)
文摘A tetrahedral silver(I) cluster complex {Ag4[HC(PPh2)3](S2PPh2)3}ClO4(1,HC(PPh2)3 = 1,1,1-tris(triphenylphosphino)methane, S2PPh2 = diphenyldithiophosphinate) was synthesized by assembling silver ion with phosphor and sulphur mixed-ligand system. The complex was characterized by single-crystal X-ray crystallography, high-resolution mass spectroscopy and thermal analysis. In the crystal structure, an inverted tetrahedron was constructed from Ag4 metal skeleton. The Ag4 cage was stabilized by three diphenyldithiophosphinate ligands and one 1,1,1-tris(triphenylphosphino)methane ligand. 1 exhibits luminescent properties in solid state. A bright yellow-green emission centered at 533 nm has been observed in solid state. Large Stokes' shifts with long range of emissive lifetime indicate that the emission likely originates from a triplet state parentage.
基金supported by the National Natural Science Foundation of China (21671175)the Program for Science & Technology Innovation Talents in Universities of Henan Province (164100510005)the Program for Innovative Research Team (in Science and Technology) in Universities of Henan Province (19IRTSTHN022) and Zhengzhou University
文摘A new 1D silver cluster-assembled complex Ag_(10)bpy-CH_3CN exhibiting intense photoluminescence was reported. Upon the loss of coordinated acetonitrile, Ag_(10)bpy-CH_3CN form Ag_(10)bpy with Ag_(10)S_6 cores slightly distorted, being accompanied with photoluminescence quenching. Inverse process can be realized by treating Ag_(10)bpy with acetonitrile and shows a selectively erasable photoluminescent switch.
文摘Resistive switching Ag/Ag2S nanoclusters were formed by sulphidation of melting-dispersed thin and continuous Ag films. The morphology, structure and electrical properties of the prepared clusters were characterized by scanning (SEM), transmitting electron (TEM), scanning resistance microscopes (SRM) and Raman scattering. Hysteretic resistive switching behavior was observed in the samples that were studied with ON/OFF switching voltage equal to 8 - 10 V respectively. Simple empirical numerical simulation model, based on Deal-Grove model assumptions and mechanisms, for silver nanoclusters sulphidation process, was proposed.
