Adsorption geometry of glycine on Cu（001） determined with low—energy electron diffraction and scanning tunnelling microscopy

Using low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) it has been found that glycine molecules adsorbed on Cu(001) can form but only the (2×4) and c(2×4) superstructures. On the basis of the missing LEED spots of the surface, it has been concluded that: each (2×4) unit cell consists of two molecules, one being the mirror image of the other; the C－C axis of both molecules lies in the mirror plane of the Cu substrate without a significant shift and twist from the plane; and the two O atoms of the carboxylate group of both molecules locate at the same height level without significant buckling. According to these conclusions, a structural model has been proposed for the (2×4) superstructure (a model for the c(2×4) superstructure already exists). We argue that the (2×4) and c(2×4) superstructures must have similar specific surface free energy, that their hydrogen bonds must be of N-H-O_II type, and that their local adsorption geometry must be similar or even the same. The advantage of combining STM with LEED to determine surface structures is clearly demonstrated.     

Synthesis and Electrochemical,Fluorescent and Magnetic Properties of a New Cadmium(II) Complex with 2-Benzoylbenzoic Acid

A new cadmium(II) complex Cd(OBBA)2(2,2A-bipy)2 with 2-benzoylbenzoic acid(HOBBA) and 2,2-bipyridine(2,2A-bipy) as ligands has been synthesized. Crystal data for the complex are as follows: monoclinic, space group P21/c with a = 16.402(3), b = 10.4191(18), c = 23.395(4) A, β = 91.765(2)o, V = 3996.2(12) A3, Dc = 1.455 gAcm-3, Z = 4, μ(Mo Kα) = 0.603 mm-1, F(000) = 1784, the final R = 0.0218 and w R = 0.0558. In the electrode reaction, its electron transfer is quasi reversible and the electrode reaction corresponds to Cd(II)/Cd(0). Under 618 nm radiation, the title complex shows a strong fluorescent band at around 326 nm. In addition, in the range of 2~300 K, this complex displays diamagnetic property.     

CuCo/BNNSs纳米催化剂对固态储氢材料氨硼烷水解的催化性能

采用共还原法将CuCo双金属负载到通过聚乙烯吡咯烷酮(PVP)辅助离子插层法制备的少层氮化硼纳米片(BNNSs)上,获得了平均粒径为2.7 nm且高度分散的铜钴/氮化硼纳米片(CuCo/BNNSs)纳米催化剂。通过原子力显微镜(AFM)、X射线衍射(XRD)、傅里叶转换红外光谱(FTIR)、拉曼光谱(Raman)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和高分辨率透射电镜(HRTEM)对载体及催化剂的结构及形貌进行表征,并研究了CuCo/BNNSs的催化性能。研究发现,由于Cu、Co、BNNSs和OH-之间高效的四重效应协同使得Cu0.5Co0.5/BNNSs纳米催化剂在室温、pH=14条件下对氨硼烷(AB,NH3BH3)水解释氢具有极高的催化活性。转化频率(TOF)值达到104.52 molH2·molmetal^-1·min^-1,且CuCo/BNNSs纳米催化剂具有良好的稳定性,6次循环利用后仍保持较高催化活性。     

添加型磷腈类阻燃剂在高分子材料中的应用

添加型磷腈类阻燃剂具有热稳定性好、耐候性好、低烟、低毒、低添加量和吸潮性低等优点,在阻燃高分子材料领域得到广泛应用。综述了近些年来国内外添加型磷腈类阻燃剂在高分子材料中的应用研究进展,分析了磷腈阻燃剂阻燃高分子材料的研究现状,为新型磷腈类阻燃剂的研发提供参考。     

Collective behavior of artificial intelligence population: transition from optimization to game

Nonlinear Dynamics - Collective behavior in the resource allocation systems has attracted much attention, where the efficiency of the system is intimately depended on the self-organized processes...     

大学有机化学教学中类比思维的培养与实践

大学有机化学课程是培养类比思维的重要阵地之一。基于类比思维的内涵以及在有机化学学习中的重要作用，探讨了大学有机化学教学中对学生类比思维的培养和实践体会，希望提高学生有机化学学习效率，以及培养大学生解决新问题的创新思维能力。     

2-苯甲酰苯甲酸铜配合物的合成、电化学、荧光及磁性研究

以2-苯甲酰苯甲酸(HL)和1,10-邻菲啰啉(Phen)为配体合成了一个新的铜(Ⅱ)配合物{[Cu2(Phen)4(NO3)][Cu(Phen)2(L)]2(L)2(NO3)3}·2H2O(1)。该化合物晶体属三斜晶系,空间群P1,晶胞参数:a=1.138 57(5)nm,b=1.193 49(7)nm,c=2.615 31(13)nm,α=89.428 0(10)°,β=82.753(2)°,γ=74.537 0(10)°,V=3.3968(3)nm3,Dc=1.408 g·cm-3,Z=1,μ(Mo Kα)=0.700 mm-1,F(000)=1 480,最终偏离因子R1=0.057 1,wR2=0.133 4。在标题配合物分子中,有2个单核阳离子[Cu(Phen)2(L)]+和1个双核阳离子[Cu2(Phen)4(NO3)]3+,中心铜(Ⅱ)离子的配位数都是五。测定了标题配合物的电化学、荧光和磁性。结果表明:在循环伏安过程中,配合物的电子转移是准可逆的,对应的电极反应是Cu(Ⅱ)/Cu(Ⅰ);当激发波长为488 nm时,配合物在494 nm附近有较强的荧光发射峰;在300～52 K,配合物具有抗磁性。     

一维链状锰配合物[Mn3(L)6(CH3OH)2]n·0.5nH2O的水热合成和晶体结构

The title compound, [Mn3(L)6(CH3OH)2]n·0.5nH2O (1), where HL=3,5-dirnethylbenzoic acid, was synthesized and its crystal structure was determined by X-ray diffraction structure analysis. The crystal is of triclinic,space group P1 with α=1.275 1(13) nm, b=1.354 6(14) nm, c=1.882 3(19) nm, α=110.826(1)°,β=94.358(2)°,γ=108.038(1)°, V=2.825 4(5) nm3, Z=1, Mr=2 265.77, Dc=1.332 g·cm-3,μ=0.723 mm-1, F(000)=1180, Rint=0.037, R=0.056 4, wR=0.128 5. In the crystal the manganese atom is six-coordinated by six oxygen atoms, completing an octahedral geometry. The molecules are connected by 3,5-dimethylbenzoic acid to form a 1D chain structure bridged. CCDC: 694097.     

锌(Ⅱ)配合物Zn(2-PMBBA)2(Phen)的合成、电化学、磁性及荧光性能研究

以2-(对甲基苯甲酰基)苯甲酸(2-PMBBA)和1,10-邻菲啰啉(Phen)为配体合成了一个新的锌(Ⅱ)配合物Zn(2-PMBBA)₂(Phen)。该配合物晶体属正交晶系,空间群Pccn,晶胞参数：a=1.371 6(4) nm,b=1.336 8(4) nm,c=1.928 7(5) nm,V=3.536 4(17) nm³,D_c=1.360 g·cm^-3,Z=4,μ(Mo Kα)=0.746 mm^-1,F(000)=1 496,最终偏离因子R₁=0.035 8,wR₂=0.086 1。在标题配合物中,中心锌(Ⅱ)离子的配位数是4,处于变形的四面体配位环境中,这是不多见的。本工作还测定了标题配合物的电化学、磁性及荧光性能。结果表明：循环伏安过程中,配合物的电子转移是不可逆的,对应的电极反应是Zn(Ⅱ)/Zn(0);在300~7 K,配合物有抗磁性;当激发波长为224 nm时,配合物在450和472 nm处有强的荧光发射峰。     

虾青素的合成

以α-紫罗兰酮为起始原料, 采用2C₁₅＋C₁₀→C₄₀路线合成了虾青素. 并经过选择性环氧化三甲基硅基烯醇醚双键的关键步骤, 设计并完成了关键中间体C₁₅部分——6-羟基-3-(3-羟基-3-甲基-1,4-戊二烯)-2,4,4-三甲基-2-环己烯-1-酮的合成.