硼氮杂薁基[4]螺烯的设计合成及性质研究※

本工作设计合成了分别含有B—N键和C=C键的薁基[4]螺烯类分子1a/1b和2, 其中B—N键和C=C键互为等电子体. 紫外-可见吸收光谱、电化学循环伏安测试和理论计算结果表明B—N键可以调控共轭骨架的电子结构及芳香性. 单晶结构表明1a具有螺旋几何构型, 晶体中存在P和M两种对映异构体. B—N键具有部分双键性质, 硼氮六元环具有一定的芳香性. 大位阻基团2,4,6-三甲基苯基(Mes)使得1b在三氟乙酸(TFA)作用下不会发生类似于1a的脱硼化, 而是发生和2相似的可逆质子响应, B—N键对薁单元的质子响应性质无明显影响. 三配位的硼原子可以进一步和氟离子配位, 使得1a对氟离子有明显的选择性响应, 而1b则因大位阻的Mes取代基的存在对氟离子无明显的响应性. 本工作报道了新型薁基硼氮杂螺烯及全碳螺烯分子, 为薁基多环芳烃的“自下而上”合成及性质研究提供了参考.     

First-principles study of fundamental properties and electronic structure of alloys

We have performed first-principles calculations using full-potential augmented-plane-wave method to investigate the fundamental properties of the Cd_1–xZn_xTe alloys. The composition dependence of the lattice constant and the bulk modulus have been estimated from total energy calculations. By means of the analytical fitting the band structures in the vicinity of the Brillouin center a complete set of effective electron- and hole-masses have also been derived. In order to further understand the effects of the chemical bonding on the above macroscopic properties we then studied the relaxation behaviors and the changes of the electronic states upon alloying for x=0.25 system. The results presented here yield a general understanding of the fundamental properties for the Cd_1–xZn_xTe crystals studies.     

Selective adsorption behaviors of guest molecules COR in the hexamer host networks at liquid/solid interface

Here,the selective adsorption behaviors of guest molecule COR in two hexamer host grids were investigated by means of scanning tunnelling microscope(STM).The assembled structures of small functional organic molecules TTBTA and TATBA were thermodynamically stable.Interestingly,the introduction of the guest molecule COR destroyed the original hexamer structure of TTBTA and combined with it to form a new triangular host-guest system.Different from TTBTA,the introduction of the guest molecule COR did not affect the six-membered ring structure of TATBA.Furthermore,the co-assembly structure of TTBTA/TATBA/COR was established and the guest molecule COR showed preferential adsorption to the TATBA host grid.Density functional theory(DFT) calculations had been performed to disclose the mechanism of the involved assemblies.     

Determination of Trace Elements in Marine Cetaceans by ICP-MS and Health Risk AssessmentSCIEI北大核心CSCD

The liver, kidney and muscle samples from seven cetaceans were digested by microwave digestion, and trace elements amounts of V, Cd, Cu, Zn, As, Cr, Ni, Mn, Se, Hg and Pb were determined by inductively coupled plasma mass spectrometry (ICP-MS), and the health risk assessment for Zn, Cu, Cd, Hg, Se in the liver was conducted. The results of international lobster hepatopancreas standard (TORT-2) showed acceptable agreement with the certified values, and the relative standard deviation (RSD) of eleven kinds of trace elements were less than 3.54%, showing that the method is suitable for the determination of trace elements in cetaceans. The experimental results indicated that different tissues and organs of the dolphins had different trace elements, presenting the tissue specificity. There is a certain inter-species difference among different dolphins about the bioaccumulation ability of the trace elements. The distribution of trace elements in whales presented a certain regularity: the contents of most elements in liver, kidney were much higher than the contents of muscle tissues, Cu, Mn, Hg, Se, and Zn exhibit the higher concentrations in liver, while Cd was mainly accumulated in kidney. And according to the health risk assessment in liver, the exceeding standardrate of selenium and copper in seven kinds of whales was 100%, suggesting that these whales were suffering the contamination of trace elements. The experimental results is instructive to the study of trace elements in cetaceans, while this is the first report for the concentrations in organs of Striped dolphin, Bottlenose dolphin, Fraser's Dolphin and Risso's dolphin in China, it may provide us valuable data for the conservation of cetaceans.     

Novel 1D Mn(II) complexes containing aromatic dicarboxylic acids

Three Mn(II) complexes of [MnL(Bipy)(H₂O)] _n (I), [Mn₃(Phen)₂(HL)₂(L)₂]n (II), and [Mn(Phen)₂(HL)(OH)] (III), where L = 4,4′-(2-acetylpropane-1,3-diyl)dibenzoic acid, Bipy = 2,2′-bipyridine, and Phen = 1,10-phenanthroline, were hydrothermally synthesized and characterized by single crystal X-ray diffractions, infrared spectroscopy, thermogravimetric analyses, and magnetic analyses. Complexes I and II are one dimensional (1D) coordination polymers which can form the supramolecules with the help of the intermolecular hydrogen bond interactions. Finally, the landé factors are simulated by magentochemical analysis to be 2.15 and 1.80 for I and II with S = 5/2, respectively.     

Thermal stability of several polyaniline/rare earth oxide composites

Polyaniline/rare earth oxide composites (PANI/La₂O₃ and PANI/Sm₂O₃) were synthesized by in situ polymerization at the presence of sulfosalicylic acid (as dopant). The composites obtained were characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability of the composites was investigated by thermogravimetry (TG) and derivative thermogravimetry (DTG). The electrochemical performance of the composites was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results of FTIR, XRD, SEM, CV, and EIS show that the structure of composite has changed greatly when rare earth oxide content is >0.7 g (PANI/La₂O₃[w/w(92.7/7.3)] and PANI/Sm₂O₃[w/w(96.2/3.8)]) and the PANI in the composite has transformed into pernigraniline base (non-conducting state) from emeraldine base (conducting state). TG-DTG analysis indicates that the thermal stability of composite was higher than pure PANI, which is attributed to the interaction between PANI and rare earth oxide.