Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (...Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (n=12-18) were performed at the HF/cc-pVDZ level. Cage N_ 24 (D_ 6d ), N_ 24 (O_h), N_ 26 (D_ 6d ), N_ 28 (T_d), N_ 30 (D_ 5h ), N_ 32 (D_ 3d ), N_ 36 (D_ 2d ) and N_ 36 (D_ 6h ) were found to be local minima on the potential energy surfaces. The computational results show that all the bond lengths of the eight structures are close to 0.145 nm and their bond energies E_ N-N are near to the experimental data of N-N single-bond. In addition, the thermochemical data of these nitrogen cages indicated that they are stable. It suggests that they are candidates for high energy density materials.展开更多
Remarkable progress was made in the development of white-light-emitting diodes （LEDs）. White LEDs provided a light element having a semiconductor InGaN light-emitting chip （blue or UV LEDs） and luminescent phospho...Remarkable progress was made in the development of white-light-emitting diodes （LEDs）. White LEDs provided a light element having a semiconductor InGaN light-emitting chip （blue or UV LEDs） and luminescent phosphors. Here we reported the sialon s-phase of （Sr,Eu）2A12Si10N14O4. Eu^2＋ activator ions that were substituted for the strontium site represented a new type of yeUow-green phosphor that could be excited by blue LEDs used for application in the fabrication of white LEDs.展开更多
The title compound (C14H12N2O2, Mr = 240.26) crystallizes in the monoclinic system, space group P21/a with a = 7.394(1), b = 21.334(3), c = 7.423(1) ? b = 89.82(1)? V = 1170.8(3) ?, Z = 4, Dc = 1.363 g/cm3, m(MoKa) = ...The title compound (C14H12N2O2, Mr = 240.26) crystallizes in the monoclinic system, space group P21/a with a = 7.394(1), b = 21.334(3), c = 7.423(1) ? b = 89.82(1)? V = 1170.8(3) ?, Z = 4, Dc = 1.363 g/cm3, m(MoKa) = 0.93 cm-1 and F(000) = 504.00. The final R and wR are 0.0440 and 0.1370 for 2153 observed reflections (I > 2s(I)), respectively. The dihedral angle between the two phenyl rings is 52.9 and that between the NO2 group and its attached ring is 3.0. In the crystal, molecules are stacked along [100] through p…p interactions. The CH…O hydrogen bond (3.403 ? 120.4? laterally connects the stacks along [010] to form networks (001) which are further anti- parallelly connected by CH…O (3.382 ? 142.9) and p…p interactions extending along [001]. Also presented here is a brief study on the CH…O hydrogen bonds in nitro-substituted benzyl-ideneanilines which can be classified into five types, namely, )5(12R, )4(21R, )8(22R, )6(12R and )7(22R, with the first three occurring more often.展开更多
Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination...Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination of the CALYPSO code and density functional theory(DFT)optimization is employed to explore the structural properties of neutral and anionic Mg_(n+1) and SrMgn(n=2-12)clusters.The results exhibit that as the atomic number of Mg increases,Sr atoms are more likely to replace Mg atoms located in the skeleton convex cap.By analyzing the binding energy,second-order energy difference and the charge transfer,it can be found the SrMg9 cluster with tower framework presents outstanding stability in a studied size range.Further,bonding characteristic analysis reveals that the stability of SrMg9 can be improved due to the strong s-p interaction among the atomic orbitals of Sr and Mg atoms.展开更多
The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by element...The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by elemental analysis, IR, 1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group C2/c with a = 24.221(6), b = 9.016(2), c = 17.003(5) ? b = 93.16(1), V = 3707(2) ?, Mr = 358.38, Z = 8, Dc = 1.284 g/cm3, m(MoKa) = 0.087 mm-1, F(000) = 1504, the final R = 0.0432 and wR = 0.1085. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and O(1) form a boat-form six-membered ring in which the C(1)C(2) (1.349(3) ? is a C=C double bond.展开更多
The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1....The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1.578 g/cm3, F(000) = 284 and μ(MoKa) = 0.136 mm-1. The final R = 0.0400 and wR = 0.0951 for 1468 observed reflections with I > 2σ(I). The title compound is a 1:1 adduct of sarcosine and 5-nitrosalicylic acid. The nitrogen atom of sarcosine is protonated, and the proton is from the carboxyl group of sarcosine and 5-nitrosalicylic acid with the probability of 50 percent for each. The 5-nitrosalicylic acid and sarcosine molecule of the title adduct are ABAB arranged along the c axis. There exist a lot of hydrogen bonds in the structure, linking sarcosine and 5-nitrosalicylic acid to form a three-dimensional network.展开更多
文摘Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (n=12-18) were performed at the HF/cc-pVDZ level. Cage N_ 24 (D_ 6d ), N_ 24 (O_h), N_ 26 (D_ 6d ), N_ 28 (T_d), N_ 30 (D_ 5h ), N_ 32 (D_ 3d ), N_ 36 (D_ 2d ) and N_ 36 (D_ 6h ) were found to be local minima on the potential energy surfaces. The computational results show that all the bond lengths of the eight structures are close to 0.145 nm and their bond energies E_ N-N are near to the experimental data of N-N single-bond. In addition, the thermochemical data of these nitrogen cages indicated that they are stable. It suggests that they are candidates for high energy density materials.
基金Project supported by the Economic Affair (95-EC-17-A-07-S1-043)the National Science Council (94-2113-M-002-030)
文摘Remarkable progress was made in the development of white-light-emitting diodes （LEDs）. White LEDs provided a light element having a semiconductor InGaN light-emitting chip （blue or UV LEDs） and luminescent phosphors. Here we reported the sialon s-phase of （Sr,Eu）2A12Si10N14O4. Eu^2＋ activator ions that were substituted for the strontium site represented a new type of yeUow-green phosphor that could be excited by blue LEDs used for application in the fabrication of white LEDs.
文摘The title compound (C14H12N2O2, Mr = 240.26) crystallizes in the monoclinic system, space group P21/a with a = 7.394(1), b = 21.334(3), c = 7.423(1) ? b = 89.82(1)? V = 1170.8(3) ?, Z = 4, Dc = 1.363 g/cm3, m(MoKa) = 0.93 cm-1 and F(000) = 504.00. The final R and wR are 0.0440 and 0.1370 for 2153 observed reflections (I > 2s(I)), respectively. The dihedral angle between the two phenyl rings is 52.9 and that between the NO2 group and its attached ring is 3.0. In the crystal, molecules are stacked along [100] through p…p interactions. The CH…O hydrogen bond (3.403 ? 120.4? laterally connects the stacks along [010] to form networks (001) which are further anti- parallelly connected by CH…O (3.382 ? 142.9) and p…p interactions extending along [001]. Also presented here is a brief study on the CH…O hydrogen bonds in nitro-substituted benzyl-ideneanilines which can be classified into five types, namely, )5(12R, )4(21R, )8(22R, )6(12R and )7(22R, with the first three occurring more often.
基金the National Natural Science Foundation of China(Grant No.11404008)the Artificial Intelligence Key Laboratory of Sichuan Province,China(Grant No.2018RYJ07)+2 种基金the Innovation Fund of Postgraduate Sichuan University of Science&Engineering,China(Grant Nos.y202007 and y2021008)the Innovation and Entrepreneurship Training Program of Sichuan Province,China(Grant Nos.S202010622080 and S202010622082)the Innovation and Entrepreneurship Training Program of Sichuan University of Science&Engineering,China(Grant No.cx2019005)。
文摘Divalent metal clusters have received great attention due to the interesting size-induced nonmetal-to-metal transition and fascinating properties dependent on cluster size,shape,and doping.In this work,the combination of the CALYPSO code and density functional theory(DFT)optimization is employed to explore the structural properties of neutral and anionic Mg_(n+1) and SrMgn(n=2-12)clusters.The results exhibit that as the atomic number of Mg increases,Sr atoms are more likely to replace Mg atoms located in the skeleton convex cap.By analyzing the binding energy,second-order energy difference and the charge transfer,it can be found the SrMg9 cluster with tower framework presents outstanding stability in a studied size range.Further,bonding characteristic analysis reveals that the stability of SrMg9 can be improved due to the strong s-p interaction among the atomic orbitals of Sr and Mg atoms.
文摘The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by elemental analysis, IR, 1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group C2/c with a = 24.221(6), b = 9.016(2), c = 17.003(5) ? b = 93.16(1), V = 3707(2) ?, Mr = 358.38, Z = 8, Dc = 1.284 g/cm3, m(MoKa) = 0.087 mm-1, F(000) = 1504, the final R = 0.0432 and wR = 0.1085. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and O(1) form a boat-form six-membered ring in which the C(1)C(2) (1.349(3) ? is a C=C double bond.
文摘The title compound (C10H12N2O7, Mr = 272.22) crystallizes in triclinic, space group P1 with a = 5.532(2), b = 9.760(4), c = 11.731(5) ?, α = 68.107(7), β = 89.179(7), γ = 77.830(7)o, V = 573.1(4) ?3, Z = 2, Dc = 1.578 g/cm3, F(000) = 284 and μ(MoKa) = 0.136 mm-1. The final R = 0.0400 and wR = 0.0951 for 1468 observed reflections with I > 2σ(I). The title compound is a 1:1 adduct of sarcosine and 5-nitrosalicylic acid. The nitrogen atom of sarcosine is protonated, and the proton is from the carboxyl group of sarcosine and 5-nitrosalicylic acid with the probability of 50 percent for each. The 5-nitrosalicylic acid and sarcosine molecule of the title adduct are ABAB arranged along the c axis. There exist a lot of hydrogen bonds in the structure, linking sarcosine and 5-nitrosalicylic acid to form a three-dimensional network.
