苯并咪唑衍生配体锌-铕(或铽)异金属双核配合物的合成、结构与光学性质

合成了四个锌-铕(或铽)异金属双核配合物[ZnLnL¹(NO₃)₃Py] (Ln=Eu (1), Tb (2); HL¹=1-H-2-(2-羟基-3-甲氧基苯基)苯并咪唑; Py=吡啶)和[ZnLnL²(NO₃)₃Py] (Ln=Eu (3), Tb (4); HL²=1-H-2-(2-羟基-3-甲氧基-5-溴苯基)苯并咪唑; Py=吡啶), 其中1、2、3是单晶态, 化合物4则为多晶样品; 通过单晶X射线衍射、元素分析、傅里叶变换红外光谱和电喷雾质谱对化合物进行了表征. 化合物的紫外-可见吸收光谱、荧光激发和发射光谱表明配体的激发态能量有效传递到配合物中的镧系金属离子中, 含有铽(III)离子的配合物发射出其特征发射光谱, 而含有铕(III)离子的配合物由于其它去活方式, 没有辐射出铕(III)离子的特征发射光谱.     

pH-dependent syntheses and crystal structures, characterizations, and DFT calculations of complexes with 2,2′-biimidazole and terephthalic acid ligands

The divalent transition metal complexes [Zn(L)₂(H₂O)₂](Tere) (I), [Cd(L)₂(H₂O)₂](Tere]) (II) and [Cd(L)₂(HTere)₂] (III) (L = 2,2’-biimidazole, Tere = terephthalate) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectrum, thermal analysis and single-crystal X-ray diffraction analysis. Complexes II and III have the same starting materials but possess different frame-works and are prepared from H₂Biim and H₂Tere under hydrothermal conditions with different pH values. The crystal structures show I and II have the same coordination circumstances and are coordinated by two H₂O molecules and two neutral bidentate 2,2′-biimidazole ligands. The terephthalate acts as the counter anion. In contrast, complex III contains protonated carboxylate groups coordinated to the metal centre to give neutral species. Furthermore, based on the optimized structures, molecular frontier orbitals, Mulliken charges and IR spetra of complex I and III are investigated by density functional theory. Calculated results show that the energy gap (ΔE _L-H) between HOMO and LUMO of complex III is bigger than that of I. It is revealed that complex III is more stable, and this calculated estimation corresponds with experimental analysis of TGA curves.     

Cu2O-coated polystyrene microsphere materials with enhanced photo- and photoelectro-catalytic activity

Cuprous oxide microsphere material was fabricated by electrochemical deposition using polystyrene particles as template. The samples are characterized by scanning electron microscope (SEM), X-ray diffraction, and UV–vis spectrophotometer. The SEM image shows the morphology and size of the microspheres, and the thickness of covered Cu₂O layer is about 100 nm. Due to the unique microspherical structure, the surface area is larger, and the optical absorption is better in Cu₂O microsphere material than in bulk Cu₂O film, which makes the degradation of methylene blue faster and photoelectrocatalytic oxidation of glucose stronger on Cu₂O microsphere material than on bulk Cu₂O film under visible light illumination. The enhanced photo- and photoelectro-catalytic activity makes the Cu₂O microsphere material more suitable for solar applications.     

Fe3+掺杂三维分级纳米Bi2WO6的合成及其光催化活性增强机理

利用水热法合成了Fe³⁺掺杂的三维分级纳米Bi₂WO₆,借助X射线衍射（XRD）、场发射扫描电镜（FE-SEM）、透射电镜（HRTEM）、能谱（EDS）、紫外可见漫反射（UV-Vis-DRS）等测试手段对所得样品的相组成、形貌和谱学特征进行了表征。选择罗丹明B为模型污染物研究所得样品在可见光下的催化活性。结果表明,Fe³⁺掺杂Bi₂WO₆为新颖的分级纳米结构,且Fe³⁺掺杂能有效提高Bi₂WO₆的光催化活性,Fe³⁺掺杂量对Bi₂WO₆活性的影响显著;实验结果还表明,所得Fe³⁺掺杂Bi₂WO₆催化剂的稳定性较好,易于回收。此外,还对Fe³⁺掺杂Bi₂WO₆的光催化活性增强机理进行了研究,缺电子的Fe³⁺作为电子捕获中心有利于促进光生电子-空穴对的分离,从而提高Bi₂WO₆的光催化活性。     

A novel algorithm based on visual saliency attention for localization and segmentation in rapidly-stained leukocyte images

In this paper, we propose a fast hierarchical framework of leukocyte localization and segmentation in rapidly-stained leukocyte images (RSLI) with complex backgrounds and varying illumination. The proposed framework contains two main steps. First, a nucleus saliency model based on average absolute difference is built, which locates each leukocyte precisely while effectively removes dyeing impurities and erythrocyte fragments. Secondly, two different schemes are presented for segmenting the nuclei and cytoplasm respectively. As for nuclei segmentation, to solve the overlap problem between leukocytes, we extract the nucleus lobes first and further group them. The lobes extraction is realized by the histogram-based contrast map and watershed segmentation, taking into account the saliency and similarity of nucleus color. Meanwhile, as for cytoplasm segmentation, to extract the blurry contour of the cytoplasm under instable illumination, we propose a cytoplasm enhancement based on tri-modal histogram specification, which specifically improves the contrast of cytoplasm while maintaining others. Then, the contour of cytoplasm is quickly obtained by extraction based on parameter-controlled adaptive attention window. Furthermore, the contour is corrected by concave points matching in order to solve the overlap between leukocytes and impurities. The experiments show the effectiveness of the proposed nucleus saliency model, which achieves average localization accuracy with F1-measure greater than 95%. In addition, the comparison of single leukocyte segmentation accuracy and running time has demonstrated that the proposed segmentation scheme outperforms the former approaches in RSLI.     

Fluorescence Spectroscopic Studies on the Interaction of Oleanolic Acid and its Triterpenoid Saponins Derivatives with Two Serum Albumins

The interaction of oleanolic acid (OA) and its glycosylated derivatives (LL-2 and LL-4) with human and bovine serum albumins were investigated using the methods of fluorescence spectroscopy. The spectroscopic analysis of the fluorescence quenching that occurs when OA and its derivatives interact with serum albumin indicates that these quenching constants are inversely correlated with temperature and the quenching process involves static interactions. The binding affinity of OA and OA-derived compounds to bovine serum albumin (BSA) and human serum albumin (HSA) follow the trend LL-4 > LL-2 > OA, suggesting that glycosylation of OA can facilitate its binding to serum albumins. Additionally, the binding affinity of these compounds to HSA is stronger than it is to BSA. The calculated thermodynamic parameters suggest that hydrophobic interactions dominate these interaction processes. We also found that only a single type of binding site exists for OA and its derivatives to HSA and BSA. Synchronous fluorescence results indicate that the binding of OA, LL-2 and LL-4 to BSA and HSA can lead to the conformational changes around the tryptophan residues of the two serum albumins. These results provided valuable clues to the pharmacokinetics and the pharmacologic activities of OA and its types of triterpenoid saponins derivatives.     

Synthesis and structures of copper(II) and cadmium(II) compounds based on pyridazine derivative ligands

The two new compounds [Cu(HODA)₂(H₂O)₂] · 3H₂O (I) and [Cd(HODA)₂(H₂O)₃] (II) (HODA = 6-oxo-1,6-dihydropyridazine-4-carboxylic acid) based on pyridazine derivation ligands have been synthesized and characterized by elemental analysis, infrared spectrum and X-ray single crystal diffraction. X-ray analysis shows that in compound I, Cu²⁺ ion is four-coordinated with a plane square geometry while Cu²⁺ ion in compound II is seven-coordinated with a distorted pentagonal bipyramid geometry. Both of the two units are all connected as 3D supramolecular structures by the intermolecular hydrogen bonds. Moreover, thermal gravimetric analysis of two compounds has been also investigated.     

穿插和缠绕结构配位聚合物的合成与性能研究

配位聚合物由于具有独特的结构和优异的性能,近年来受到国内外的持续广泛关注,已成为当前化学、物理、材料、医学以及生命科学等领域的热点研究之一,并日益呈现出迅猛发展的良好势头.有关此类化合物的显著特征是:在合成时,其结构中经常发生不同程度的穿插和缠绕现象,使得合成目标化合物的性能产生根本上的改变.因此,本文主要结合本课题组近期的研究工作,评述了穿插和缠绕结构配位聚合物及其相关化合物的合成、结构与气体吸附分离性能应用等方面的研究进展.     

Two New Nitrone Alkaloids from Huperzia serrata

Two new nitrone alkaloids were isolated from the whole plant of Huperzia serrata (Thunb .) Trev . They are both phlegmarine‐type lycopodium alkaloids with a nitrone moiety. Their structures were elucidated on the basis of spectral evidences, and their configurations were established on the basis of optical rotation, CD, and NOESY‐NMR data.     

An unusual asymmetric polyoxomolybdate containing mixed-valence antimony and its derivatives: [Sb4VSb2IIIMo18O73(H2O)2]12- and {M(H2O)2[Sb4VSb2IIIMo18O73(H2O)2]2}22- (M = MnII, FeII, CuII or CoII)

A new type of heteropolyanion containing mixed-valence antimony, [Sb4(V)Sb2(III)Mo18O73(H2O)2](12-) (1a), and its four derivatives, {M(H2O)2[Sb4(V)Sb2(III)Mo18O73(H2O)2]2}(22-) (M = Mn(II), Fe(II), Cu(II), or Co(II)) (2a-5a), have been isolated as ammonium salt, and their structures were determined by single-crystal X-ray diffraction. The framework of the polyanion 1a displays a curious asymmetric structure, and there exist six types of Sb coordination environments and seven types of {MoO6} octahedra. The title compounds were also characterized by elemental analyses, IR, UV-vis, Raman spectra, and cyclic voltammogramms.