The microstructure and hydrogen storage properties of low V content （Ti0.46Cr0.54）100-xVx （x = 2.5-7.1, at%） and （TiyCr1-y）95V5 （y= 0.38-0.54） alloys were investigated. These alloys were prepared by arc meltin...The microstructure and hydrogen storage properties of low V content （Ti0.46Cr0.54）100-xVx （x = 2.5-7.1, at%） and （TiyCr1-y）95V5 （y= 0.38-0.54） alloys were investigated. These alloys were prepared by arc melting and copper mould suction casting. The structures of as-cast （Ti0.46Cr0.54）100-xVx （x = 2.5, 5.0, and 7.1） alloy ingots evolve with V contents from pure Laves-（x = 2.5） to dual-phase TiCr2-BCC structures （5.0 and 7.1）, whereas the suction-cast （Ti0.46Cr0.54）100-xVx （x =2.5, 5.0, and 7.1） alloys only contain single BCC phase. The suction-cast alloy rod （Ti0.46Cr0.54）95V5, containing only 5.0 at% V is shown to possess the optimum hydrogen absorption capacity, with the maximum hydrogen content of 3.14 wt%. Furthermore, the hydrogen storage properties of the suction-cast low V alloys （TiyCr1-y）95V5 （y = 0.38-0.54） are sensitive to Ti/Cr ratios and only those alloys with Ti/Cr ratios close to the CN14 cluster [TiTCrs] have good hydrogen storage properties.展开更多
Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper io...Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical force.Significantly,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular interactions.Moreover,1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar.Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen process.This work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.展开更多
Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copp...Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copper clusters that are very close in composition,[Cu_(20)H_(9)(Tf-dpf)_(10)]·BF4(Cu_(20)H_(9))and[Cu_(20)H_(8)(Tf-dpf)_(10)]·(BF_(4))_(2)(Cu_(20)H_(8)),by using a pyridyl-functionalized flexible amidinate ligand,N,N′-di(5-trifluoromethyl-2-pyridyl)formamidinate.The one-hydride difference in their composition leads to significant variation in geometric and electronic structures and,consequently,distinctly different optical and catalytic properties.Cu_(20)H_(8)exhibits 25 times higher catalytic activity than Cu_(20)H_(9)(96.7%vs 3.7%in yield)in the selective hydrogenation of anα,β-unsaturated aldehyde(cinnamaldehyde)to saturated aldehyde(3-phenylpropanal).Electrospray ionization mass spectrometry combined with density functional theory calculations reveal that the greater ease of dissociation of one Tf-dpf ligand compared to Cu_(20)H_(8)is the key to its higher activity.This work demonstrates a clear case of structure and composition sensitivity in nanocatalysis and that one hydride,out of∼330 atoms in the nanoclusters,can make a huge difference in the catalytic activity.These insights will be useful in the design and synthesis of atomically precise nanocatalysts.展开更多
Reaction of a preformed cluster （Et4N）2[MoS4（CuCN）2]·H2O（1） with acetic acid in MeCN gave rise to an interesting 2D polymeric cluster （Et4N）3 {[MoS4Cu2（μ-CN）]2（μ^1-CN）}·2MeCN （2）. Compound 2 ...Reaction of a preformed cluster （Et4N）2[MoS4（CuCN）2]·H2O（1） with acetic acid in MeCN gave rise to an interesting 2D polymeric cluster （Et4N）3 {[MoS4Cu2（μ-CN）]2（μ^1-CN）}·2MeCN （2）. Compound 2 was characterized by elemental analysis, IR spectrum, and single crystal X-ray crystallography. In the structure of 2, the cluster core MoS4Cu2 of the cluster precursor 1 is retained and serves as a 3-connecting node to link equivalent nodes via single cyanide bridges, forming an anionic 2D （6,3） （honeycomb-like） network. The acetic acid induced aggregation of supramolecular compound 2 from the cluster precursor 1 suggests that this simple synthetic strategy be likely applicable to many related systems.展开更多
Reaction of (NH 4) 2MoS 4 with [Cu(MeCN) 4](BF 4) and (n-Bu) 4NBr in CH 2Cl 2 afforded a new hexanuclear cluster [(n-Bu) 4N] 3[MoS 4Cu 5Br 6] (1). 1 crystallizes in the monoclinic system, space group P2 ...Reaction of (NH 4) 2MoS 4 with [Cu(MeCN) 4](BF 4) and (n-Bu) 4NBr in CH 2Cl 2 afforded a new hexanuclear cluster [(n-Bu) 4N] 3[MoS 4Cu 5Br 6] (1). 1 crystallizes in the monoclinic system, space group P2 1/c, with lattice parameters a=1.17383(4) nm, b=2.40136(4) nm, c=2.64112(5) nm, β=94.2020(5)°, V=7.4247(5) nm 3 and Z=4. The structure of the [MoS 4Cu 5Br 6] 3- trianion of 1 is composed of one nido-like [MoS 3Cu 3] core and one half-open cubane-like [MoS 3Cu 3Br] core, which are interconnected by sharing the same MoSCuS plane. The Mo...Cu distances vary in the range of 0.2622(6)-0.2692(5) nm.展开更多
A new octanuclear VSCu cluster {V2S6Cu6}(PPh3)6(O)22CH2Cl2CH3OH 1 has been prepared by extraction with CH2Cl2 of a solid mixture of (NH4)3VS4, Cu(PPh3)2Cl and NEt4Br, and its structure has been determined by single-cr...A new octanuclear VSCu cluster {V2S6Cu6}(PPh3)6(O)22CH2Cl2CH3OH 1 has been prepared by extraction with CH2Cl2 of a solid mixture of (NH4)3VS4, Cu(PPh3)2Cl and NEt4Br, and its structure has been determined by single-crystal X-ray diffraction. Crystallographic data: C111H98Cl4Cu6O3P6S6V2, Mr = 2248.99, triclinic space group P , a = 13.751(6), b = 15.509(4), c = 15.642(5) ? a =114.34(2), b = 98.35(3), g = 110.43(3) , V = 2679.83 3, Z = 1, Dc = 1.538 g/cm3, F(000) = 1262, m (MoKa) = 16.9 cm-1, the final R = 0.079 and Rw = 0.083 for 5504 observed reflections with I > 2s(I). The structural determination shows that the skeleton can be described as a metal-sulfur dodecahedral cage fused by two incomplete cubane-like [VS3Cu3] subunits centrosymmetrically connected by CuS and weak CuCu bonds. The six copper and two vanadium atoms display a slightly distorted cubic array with a m4-S atom on each face of the metal cube. The selected IR, electronic and 51V NMR spectra have also been reported.展开更多
Reaction of [PPh_4][(η 5-C_5Me_5)WS_3] with CuI,CuBr and bis^(diphenylphosphino)methane (dppm) (molar ratio=1∶2∶1∶1) in MeCN gave rise to [PPh_4][(η 5-C_5Me_5)WS_3(CuBr)(CuI)_2-(μ-dppm)] (1) in high yield. Com...Reaction of [PPh_4][(η 5-C_5Me_5)WS_3] with CuI,CuBr and bis^(diphenylphosphino)methane (dppm) (molar ratio=1∶2∶1∶1) in MeCN gave rise to [PPh_4][(η 5-C_5Me_5)WS_3(CuBr)(CuI)_2-(μ-dppm)] (1) in high yield. Compound 1 crystallizes in the monoclinic,space group P2_1/n with lattice parameters:a=1.2906(4) nm, b=1.5006(8) nm,c=3.1484(6) nm,β= 92.12(2)°,V=6.093(3) nm 3,Z=4. The structure of the anion of 1 contains an incomplete WS_3Cu_3 cubane-like core in which two CuI units are bridged by a dppm ligand. The W—Cu distances vary in the range of 0.2644(1)—0.2793(1) nm. The optical limiting (OL) properties of 1 in MeCN were measured with the laser pulse-width of 12-ns at 532 nm,and the nanosecond OL effect may be due to the reverse saturable absorption (RSA) related to the excited triplet states.展开更多
Three kinds of complexes,V_2Cu_2S_4 cubane-like,VS_4Cu_4 planar and V_3S_7 triangular dusters are obtained from a reaction system composed of(NH_4)_3VS_4,CuCl,R_2dtcNa and PhSNa.A mechanism of the formation of the pro...Three kinds of complexes,V_2Cu_2S_4 cubane-like,VS_4Cu_4 planar and V_3S_7 triangular dusters are obtained from a reaction system composed of(NH_4)_3VS_4,CuCl,R_2dtcNa and PhSNa.A mechanism of the formation of the products is suggested.The title compound is structurally characterized,showing the metal oxidation states of V(IV)+Cu(I).Also discussed are IR,UV-Vis and NMR spectra,and cyclic voltagrammetry for the V_2Cu_2S_4 clusters.展开更多
The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc...The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc=1. 57 g/cm3,μ= 19. 6 cm-1,F(000)=2160. Final R=0.074(Rw=0.082) for 2662 unique reflections with I≥3σ(I). The V atom in the compound retains the tetrahedral geometry of the VS3O with S-V-S or S-V-O angles of 108.6(6)～110.3 (6)°.The cluster core [V2Cu6S6O2] of the compound can be regarded as two cluster cores [VCu3S3O] bonded by bondings of the Cu-Cu'(distances of 2.774(3)～2.707(5) A) and Cu-S (distances of 2.463(7)～2.396(9) A) with centrosymmetric. Atoms of the cluster core V2Cu6 form a distorted cube with the Cu Cu'or the V-Cu distances of 2. 774(3)～2. 707(5) A.展开更多
The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average bind...The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average binding energy per atom, first difference energy and second difference energy of copper cluster. Most of the copper clusters of the size n=70-150 adopt an icosahedral structure. The results show that the trends are in agreement with theoretic prediction for copper clusters. The most stable structures for copper clusters are found at n=77, 90, 95, 131, 139.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51171035 and 11174044)
文摘The microstructure and hydrogen storage properties of low V content （Ti0.46Cr0.54）100-xVx （x = 2.5-7.1, at%） and （TiyCr1-y）95V5 （y= 0.38-0.54） alloys were investigated. These alloys were prepared by arc melting and copper mould suction casting. The structures of as-cast （Ti0.46Cr0.54）100-xVx （x = 2.5, 5.0, and 7.1） alloy ingots evolve with V contents from pure Laves-（x = 2.5） to dual-phase TiCr2-BCC structures （5.0 and 7.1）, whereas the suction-cast （Ti0.46Cr0.54）100-xVx （x =2.5, 5.0, and 7.1） alloys only contain single BCC phase. The suction-cast alloy rod （Ti0.46Cr0.54）95V5, containing only 5.0 at% V is shown to possess the optimum hydrogen absorption capacity, with the maximum hydrogen content of 3.14 wt%. Furthermore, the hydrogen storage properties of the suction-cast low V alloys （TiyCr1-y）95V5 （y = 0.38-0.54） are sensitive to Ti/Cr ratios and only those alloys with Ti/Cr ratios close to the CN14 cluster [TiTCrs] have good hydrogen storage properties.
基金supported by the National Natural Science Foundation of China(92061201,21825106,22371264,22301283)the Excellent Young Scientist Fundation of Henan Province(202300410374)+1 种基金the Program for Science&Technology Innovation Talents in Universities of Henan Province(22HASTIT002)Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(234000510007)。
文摘Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications.In this work,a new copper iodide cluster(1)with aggregationinduced emission(AIE)characteristic,was obtained combining Cu_(4)I_(4) core with rhodamine B derivative ligand.1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature,volatile organic compound,and mechanical force.Significantly,1 exhibited unusual large blue shift(84 nm)after being ground,which originated from the change of intermolecular interactions.Moreover,1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar.Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process,metal-to-ligand charge transfer process,halide-to-metal charge transfer luminescence process and aggregationinduced barrier to oxygen process.This work not only reports an AIE copper iodide cluster,but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.
基金supported by the National Natural Science Foundation of China(grant nos.91961201 and 21973116)the Beijing Natural Science Foundation(grant no.2234087)the China Postdoctoral Science Foundation(grant nos.2023T160357 and 2022M721797).
文摘Sensitivity to structure and composition is very challenging to establish in nanocatalysis due to inadequate definition of structures that are very close in composition.We synthesized a pair of atomically precise copper clusters that are very close in composition,[Cu_(20)H_(9)(Tf-dpf)_(10)]·BF4(Cu_(20)H_(9))and[Cu_(20)H_(8)(Tf-dpf)_(10)]·(BF_(4))_(2)(Cu_(20)H_(8)),by using a pyridyl-functionalized flexible amidinate ligand,N,N′-di(5-trifluoromethyl-2-pyridyl)formamidinate.The one-hydride difference in their composition leads to significant variation in geometric and electronic structures and,consequently,distinctly different optical and catalytic properties.Cu_(20)H_(8)exhibits 25 times higher catalytic activity than Cu_(20)H_(9)(96.7%vs 3.7%in yield)in the selective hydrogenation of anα,β-unsaturated aldehyde(cinnamaldehyde)to saturated aldehyde(3-phenylpropanal).Electrospray ionization mass spectrometry combined with density functional theory calculations reveal that the greater ease of dissociation of one Tf-dpf ligand compared to Cu_(20)H_(8)is the key to its higher activity.This work demonstrates a clear case of structure and composition sensitivity in nanocatalysis and that one hydride,out of∼330 atoms in the nanoclusters,can make a huge difference in the catalytic activity.These insights will be useful in the design and synthesis of atomically precise nanocatalysts.
基金Project supported by the National Natural Science Foundation of China （No. 20271036）, the Natural Science Foundation of Jiangsu Province （No. BK2004205）, the Natural Science Foundation of the Education Committee of Jiangsu Province （No. 03KJD 150241 ）, and the Key Laboratory of 0rganic Synthesis of Jiangsu Province （No. JSK001 ） in China.
文摘Reaction of a preformed cluster （Et4N）2[MoS4（CuCN）2]·H2O（1） with acetic acid in MeCN gave rise to an interesting 2D polymeric cluster （Et4N）3 {[MoS4Cu2（μ-CN）]2（μ^1-CN）}·2MeCN （2）. Compound 2 was characterized by elemental analysis, IR spectrum, and single crystal X-ray crystallography. In the structure of 2, the cluster core MoS4Cu2 of the cluster precursor 1 is retained and serves as a 3-connecting node to link equivalent nodes via single cyanide bridges, forming an anionic 2D （6,3） （honeycomb-like） network. The acetic acid induced aggregation of supramolecular compound 2 from the cluster precursor 1 suggests that this simple synthetic strategy be likely applicable to many related systems.
基金theKeyLaboratoryofOrganicChemistryofJiangsuProvince (No .KJS0 1017)andtheStateKeyLaboratoryofCoordinationChemistryofNanjingUniversity
文摘Reaction of (NH 4) 2MoS 4 with [Cu(MeCN) 4](BF 4) and (n-Bu) 4NBr in CH 2Cl 2 afforded a new hexanuclear cluster [(n-Bu) 4N] 3[MoS 4Cu 5Br 6] (1). 1 crystallizes in the monoclinic system, space group P2 1/c, with lattice parameters a=1.17383(4) nm, b=2.40136(4) nm, c=2.64112(5) nm, β=94.2020(5)°, V=7.4247(5) nm 3 and Z=4. The structure of the [MoS 4Cu 5Br 6] 3- trianion of 1 is composed of one nido-like [MoS 3Cu 3] core and one half-open cubane-like [MoS 3Cu 3Br] core, which are interconnected by sharing the same MoSCuS plane. The Mo...Cu distances vary in the range of 0.2622(6)-0.2692(5) nm.
基金the Natural Science Foundation of China Fujian Province and Chinese Academy of Sciences.
文摘A new octanuclear VSCu cluster {V2S6Cu6}(PPh3)6(O)22CH2Cl2CH3OH 1 has been prepared by extraction with CH2Cl2 of a solid mixture of (NH4)3VS4, Cu(PPh3)2Cl and NEt4Br, and its structure has been determined by single-crystal X-ray diffraction. Crystallographic data: C111H98Cl4Cu6O3P6S6V2, Mr = 2248.99, triclinic space group P , a = 13.751(6), b = 15.509(4), c = 15.642(5) ? a =114.34(2), b = 98.35(3), g = 110.43(3) , V = 2679.83 3, Z = 1, Dc = 1.538 g/cm3, F(000) = 1262, m (MoKa) = 16.9 cm-1, the final R = 0.079 and Rw = 0.083 for 5504 observed reflections with I > 2s(I). The structural determination shows that the skeleton can be described as a metal-sulfur dodecahedral cage fused by two incomplete cubane-like [VS3Cu3] subunits centrosymmetrically connected by CuS and weak CuCu bonds. The six copper and two vanadium atoms display a slightly distorted cubic array with a m4-S atom on each face of the metal cube. The selected IR, electronic and 51V NMR spectra have also been reported.
基金ProjectsupportedbytheNationalNaturalScienceFoundationofChina (No .2 0 2 710 3 6) ,theNaturalScienceFoundationoftheEducationCommitteeofJiangsuProvince (No .0 2KJB15 0 0 0 1) ,StateKeyLabofCoordinationChemistryofNanjingUniversity ,andtheScientificResearchF
文摘Reaction of [PPh_4][(η 5-C_5Me_5)WS_3] with CuI,CuBr and bis^(diphenylphosphino)methane (dppm) (molar ratio=1∶2∶1∶1) in MeCN gave rise to [PPh_4][(η 5-C_5Me_5)WS_3(CuBr)(CuI)_2-(μ-dppm)] (1) in high yield. Compound 1 crystallizes in the monoclinic,space group P2_1/n with lattice parameters:a=1.2906(4) nm, b=1.5006(8) nm,c=3.1484(6) nm,β= 92.12(2)°,V=6.093(3) nm 3,Z=4. The structure of the anion of 1 contains an incomplete WS_3Cu_3 cubane-like core in which two CuI units are bridged by a dppm ligand. The W—Cu distances vary in the range of 0.2644(1)—0.2793(1) nm. The optical limiting (OL) properties of 1 in MeCN were measured with the laser pulse-width of 12-ns at 532 nm,and the nanosecond OL effect may be due to the reverse saturable absorption (RSA) related to the excited triplet states.
基金the National Natural Science Foundation of Chinathe Climbing Program Foundation of China
文摘Three kinds of complexes,V_2Cu_2S_4 cubane-like,VS_4Cu_4 planar and V_3S_7 triangular dusters are obtained from a reaction system composed of(NH_4)_3VS_4,CuCl,R_2dtcNa and PhSNa.A mechanism of the formation of the products is suggested.The title compound is structurally characterized,showing the metal oxidation states of V(IV)+Cu(I).Also discussed are IR,UV-Vis and NMR spectra,and cyclic voltagrammetry for the V_2Cu_2S_4 clusters.
文摘The title V-Cu-S heterometallic cluster compound C84 H86Cl4Cu6N2O4P4S6V2, crystallizes in the monoclinic space group P21/n with a=16.381(5), b=17.114(3),c=16.749(6) A,β=107. 04(3)°,V=4490(2)A3, Mr=2128.84,Z=2,Dc=1. 57 g/cm3,μ= 19. 6 cm-1,F(000)=2160. Final R=0.074(Rw=0.082) for 2662 unique reflections with I≥3σ(I). The V atom in the compound retains the tetrahedral geometry of the VS3O with S-V-S or S-V-O angles of 108.6(6)～110.3 (6)°.The cluster core [V2Cu6S6O2] of the compound can be regarded as two cluster cores [VCu3S3O] bonded by bondings of the Cu-Cu'(distances of 2.774(3)～2.707(5) A) and Cu-S (distances of 2.463(7)～2.396(9) A) with centrosymmetric. Atoms of the cluster core V2Cu6 form a distorted cube with the Cu Cu'or the V-Cu distances of 2. 774(3)～2. 707(5) A.
基金supported by the National Natural Science Foundation of China (Grant No 10375028)
文摘The structure and binding energy of copper clusters of the size range 70 to 150 were studied by using the embeddedatom method. The stability of the structure of the clusters was studied by calculating the average binding energy per atom, first difference energy and second difference energy of copper cluster. Most of the copper clusters of the size n=70-150 adopt an icosahedral structure. The results show that the trends are in agreement with theoretic prediction for copper clusters. The most stable structures for copper clusters are found at n=77, 90, 95, 131, 139.
