A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space g...A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space group P1 with a = 13.054(3),b = 13.137(3),c = 15.077(3) ,α = 80.009(9),β = 77.187(10),γ = 76.075(11)°,Z = 2,V = 2427.3(9) 3,Dc = 1.565 g/cm3,μ(MoKα) = 2.076 mm-1,F(000) = 1152,the final R = 0.0335 and wR = 0.0664 for 9416 observed reflections(I 2σ(I)).Cluster 2 belongs to the monoclinic system,space group P21/c with a = 13.673(3),b = 13.342(3),c = 16.296(4) ,β = 104.385(5)o,Z = 4,V = 2879.7(10) 3,Dc = 1.347 g/cm3,μ(MoKα) = 1.751 mm-1,F(000) = 1176,the final R = 0.0306 and wR = 0.0706 for 6390 observed reflections(I 2σ(I)).The crystal structures of the clusters consist of cen-trosymmetric [RCOOSnnBu2OSnnBu2OH)]2 molecules with an almost planar Sn4O4 framework.Each pair of exo-and endo-cyclic tin atoms was linked by one bridge-OH only.In addition,a novel structure of nBu2SnO different from the previous reports was proposed on the basis of 1H-NMR,TG analysis and X-ray diffraction.展开更多
Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have ...Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have been investigated by employing DV - Xa method, in which different cluster models were adopted to calculate electron structure.It is proved that some regulations must be taken into ac- count in order to carry out alloy design calculation successfully,which are described in this paper in detail.展开更多
The present multi-harmonic shell clustering of a nucleus is a direct consequence of the fermionic nature of nucleons and their average sizes. The most probable form and the average size for each proton or neutron shel...The present multi-harmonic shell clustering of a nucleus is a direct consequence of the fermionic nature of nucleons and their average sizes. The most probable form and the average size for each proton or neutron shell are here presented by a specific equilibrium polyhedron of definite size. All such polyhedral shells are closely packed leading to a shell clustering of a nucleus. A harmonic oscillator potential is employed for each shell. All magic and semi-magic numbers, g.s. single particle and total binding energies, proton, neutron and mass radii of 40Ca, 48Ca, 54Fe, 90Zr, 108Sn, 114Te, 142Nd, and 208Pb are very successfully predicted.展开更多
The structures, relative stability and magnetic properties of pure Gen+l, neutral cationic and anionic Sn- Gen (n = 1-17) clusters have been investigated by using the first principles density functional theory impl...The structures, relative stability and magnetic properties of pure Gen+l, neutral cationic and anionic Sn- Gen (n = 1-17) clusters have been investigated by using the first principles density functional theory implemented in SIESTA packages. We find that with the increasing of cluster size, the Gen+1 and SnGen(1, ±1) clusters tend to ad- opt compact structures. It has been also found that the Sn atom occupied a peripheral position for SnGen clusters when n 〈 12 and occupied a core position for n 〉 12. The structural and electronic properties such as optimized geometries, fragmentation energy, binding energy per atom, HOMO-LUMO gaps and second-order differences in energy of the pure G%+1 and SnGen clusters in their ground state are calculated and analyzed. All isomers of neutral SnG% clusters are generally nonmagnetic except for n = 1 and 4, where the total spin magnetic moments is 2μb. The total (DOS) and partial density of states of these clusters have been calculated to understand the origin of peculiar magnetic properties. The cluster size dependence of vertical ionization potentials, vertical electronic affinities, chemical hardness, adiabatic electron affinities and adiabatic ionization potentials have been calculated and discussed.展开更多
A large number of the isomers of neutral and ionic Snn(n=2-15) clusters have been designed and optimized at the level of MP2/LANL2DZ with the aid of the Gaussian 09 software package. The most stable geometric struct...A large number of the isomers of neutral and ionic Snn(n=2-15) clusters have been designed and optimized at the level of MP2/LANL2DZ with the aid of the Gaussian 09 software package. The most stable geometric structures of ionic(cationic and anionic) Sn clusters have been compared with the corresponding neutral geometries. Most structures of Snn+ and Snn are similar to each other except for the structures of those with n=5, 11 and 15; while the anions Snn- are almost different from Snn clusters with n=9--15 except for Sn12- and Snl4-. The electronic properties have been calculated, including binding energy, second difference in energy, HOMO-LUMO gaps, ionization potentials, and electron affinities.展开更多
To investigate the reactivity of homoatomic clusters[E_(9)]^(4-)(E=Si-Pb)and intermetalloid clusters[M@E_(9)]^(q-),the reactions of the Zintl anions[Sn_(9)]^(4-) and[Ni@Sn_(9)]^(4-) with the CdMes_(2)(Mes=Mesitylene)i...To investigate the reactivity of homoatomic clusters[E_(9)]^(4-)(E=Si-Pb)and intermetalloid clusters[M@E_(9)]^(q-),the reactions of the Zintl anions[Sn_(9)]^(4-) and[Ni@Sn_(9)]^(4-) with the CdMes_(2)(Mes=Mesitylene)in the presence of 2.2.2-crypt were carried out.Two new compounds[K(2.2.2-crypt)]_(6)[(Sn_(9))Cd(Sn_(9))]·en(1)and[K(2.2.2-crypt)]_(6)[(Ni@Sn_(9))Cd(Ni@Sn_(9))]·en(2)were afforded.Both 1 and 2 were characterized by single-crystal X-ray diffraction,energy dispersive X-ray(EDX),and electrospray ionization mass spectrometry(ESI-MS),and can be viewed as two[Sn_(9)]^(4-)or[Ni@Sn_(9)]^(4-)subunits bridged by Cd ion in an η^(3):η^(3) coordination mode.Quantum chemical calculations reveal the relationships between the geometries and electronic structures of clusters 2a,[Ni_(3)Ge_(18)]^(4-)and[Cu_(4)@Sn_(18)]^(4-).Further electron localization technique(Ad NDP method)was performed to explain chemical bonding patterns of 1a.展开更多
基金supported by the National Natural Science Foundation of China (20421202,20372033)
文摘A facile and credible strategy was demonstrated to synthesize two new Sn-O clusters 1 and 2 by the reactions of nBu2SnO with esters directly under mild conditions.Cluster 1 crystallizes in the triclinic system,space group P1 with a = 13.054(3),b = 13.137(3),c = 15.077(3) ,α = 80.009(9),β = 77.187(10),γ = 76.075(11)°,Z = 2,V = 2427.3(9) 3,Dc = 1.565 g/cm3,μ(MoKα) = 2.076 mm-1,F(000) = 1152,the final R = 0.0335 and wR = 0.0664 for 9416 observed reflections(I 2σ(I)).Cluster 2 belongs to the monoclinic system,space group P21/c with a = 13.673(3),b = 13.342(3),c = 16.296(4) ,β = 104.385(5)o,Z = 4,V = 2879.7(10) 3,Dc = 1.347 g/cm3,μ(MoKα) = 1.751 mm-1,F(000) = 1176,the final R = 0.0306 and wR = 0.0706 for 6390 observed reflections(I 2σ(I)).The crystal structures of the clusters consist of cen-trosymmetric [RCOOSnnBu2OSnnBu2OH)]2 molecules with an almost planar Sn4O4 framework.Each pair of exo-and endo-cyclic tin atoms was linked by one bridge-OH only.In addition,a novel structure of nBu2SnO different from the previous reports was proposed on the basis of 1H-NMR,TG analysis and X-ray diffraction.
文摘Applying calculation method in alloy design should be an important tendency due to its characters of inexpensive cost, high efficiency and prediction. DOS calculations of AuSn, AsSn and SbSn Sn- based alloys have been investigated by employing DV - Xa method, in which different cluster models were adopted to calculate electron structure.It is proved that some regulations must be taken into ac- count in order to carry out alloy design calculation successfully,which are described in this paper in detail.
文摘The present multi-harmonic shell clustering of a nucleus is a direct consequence of the fermionic nature of nucleons and their average sizes. The most probable form and the average size for each proton or neutron shell are here presented by a specific equilibrium polyhedron of definite size. All such polyhedral shells are closely packed leading to a shell clustering of a nucleus. A harmonic oscillator potential is employed for each shell. All magic and semi-magic numbers, g.s. single particle and total binding energies, proton, neutron and mass radii of 40Ca, 48Ca, 54Fe, 90Zr, 108Sn, 114Te, 142Nd, and 208Pb are very successfully predicted.
文摘The structures, relative stability and magnetic properties of pure Gen+l, neutral cationic and anionic Sn- Gen (n = 1-17) clusters have been investigated by using the first principles density functional theory implemented in SIESTA packages. We find that with the increasing of cluster size, the Gen+1 and SnGen(1, ±1) clusters tend to ad- opt compact structures. It has been also found that the Sn atom occupied a peripheral position for SnGen clusters when n 〈 12 and occupied a core position for n 〉 12. The structural and electronic properties such as optimized geometries, fragmentation energy, binding energy per atom, HOMO-LUMO gaps and second-order differences in energy of the pure G%+1 and SnGen clusters in their ground state are calculated and analyzed. All isomers of neutral SnG% clusters are generally nonmagnetic except for n = 1 and 4, where the total spin magnetic moments is 2μb. The total (DOS) and partial density of states of these clusters have been calculated to understand the origin of peculiar magnetic properties. The cluster size dependence of vertical ionization potentials, vertical electronic affinities, chemical hardness, adiabatic electron affinities and adiabatic ionization potentials have been calculated and discussed.
基金Supported by the National Natural Science Foundation of China(No.21273122).
文摘A large number of the isomers of neutral and ionic Snn(n=2-15) clusters have been designed and optimized at the level of MP2/LANL2DZ with the aid of the Gaussian 09 software package. The most stable geometric structures of ionic(cationic and anionic) Sn clusters have been compared with the corresponding neutral geometries. Most structures of Snn+ and Snn are similar to each other except for the structures of those with n=5, 11 and 15; while the anions Snn- are almost different from Snn clusters with n=9--15 except for Sn12- and Snl4-. The electronic properties have been calculated, including binding energy, second difference in energy, HOMO-LUMO gaps, ionization potentials, and electron affinities.
基金supported by the National Natural Science Foundation of China(Nos.92161102 and 21971118)the Natural Science Foundation of Tianjin City(Nos.20JCYBJC01560 and B2021202077)to Z.-M.Sun。
文摘To investigate the reactivity of homoatomic clusters[E_(9)]^(4-)(E=Si-Pb)and intermetalloid clusters[M@E_(9)]^(q-),the reactions of the Zintl anions[Sn_(9)]^(4-) and[Ni@Sn_(9)]^(4-) with the CdMes_(2)(Mes=Mesitylene)in the presence of 2.2.2-crypt were carried out.Two new compounds[K(2.2.2-crypt)]_(6)[(Sn_(9))Cd(Sn_(9))]·en(1)and[K(2.2.2-crypt)]_(6)[(Ni@Sn_(9))Cd(Ni@Sn_(9))]·en(2)were afforded.Both 1 and 2 were characterized by single-crystal X-ray diffraction,energy dispersive X-ray(EDX),and electrospray ionization mass spectrometry(ESI-MS),and can be viewed as two[Sn_(9)]^(4-)or[Ni@Sn_(9)]^(4-)subunits bridged by Cd ion in an η^(3):η^(3) coordination mode.Quantum chemical calculations reveal the relationships between the geometries and electronic structures of clusters 2a,[Ni_(3)Ge_(18)]^(4-)and[Cu_(4)@Sn_(18)]^(4-).Further electron localization technique(Ad NDP method)was performed to explain chemical bonding patterns of 1a.