Four mono-/bi-nuclear palladium(II) complexes of triphenylphosphine and heterocyclic-N/NS ligands: Synthesis, structural characterization and luminescence properties

The reactions of palladium(II) chloride, PPh₃ and heterocyclic-N/NS ligand in a mixture of CH₃CN (5 ml) and CH₃OH (5 ml) produced [PdCl₂(PPh₃)(L1)]·(CH₃CN) (1) (L1 = ADMT = 3-amino-5,6-dimethyl-1,2,4-triazine), [PdCl₂(PPh₃)(L2)] (2) (L2 = 3-CNpy = 3-cyanopyridine), [PdCl(PPh₃)(L3)]₂·(CH₃CN) (3), [PdCl(PPh₃)₂(HL3)]Cl (4) (HL3 = Hmbt = 2-mercaptobenzothiazole). The coordination geometry around the Pd atoms in these complexes is a distorted square plane. In 3, L3 acts as a bidentate ligand, bridging two metal centers, while in 4, HL3 appears as monodentate ligand with one nitrogen donor atom uncoordinated. Complexes 1-4 are characterized by IR, luminescence, NMR and single crystal X-ray diffraction analysis. All complexes exhibit luminescence in solid state at room temperature.     

溶胶-凝胶-水热法制备Ce-Si/TiO2及其可见光催化性能

以钛酸四正丁酯、正硅酸乙酯、六水硝酸铈为原料,在140℃下通过溶胶-凝胶-水热法水解制备Ce-Si/TiO2.所得样品用X射线衍射、氮吸附、透射电镜、紫外漫反射、傅里叶变换红外光谱、X射线光电子能谱等测试手段分析,结果显示400-600℃条件下焙烧所有样品均为锐钛矿,样品具有较大的比表而积,Si和Ce均被引入到TiO2中.在可见光照射下,以脱色降解罗丹明B为探针反应,研究其可见光催化性能,结果表明,与末掺杂和单一组分掺杂的二氧化钛相比较,共掺杂的二氧化钛具有更高的催化性能,当Ce/Ti和Si/Ti的物质的量比分别为0.010和0.10时,可见光催化性能最好.     

微波辐照促进的甲醇水蒸汽重整制氢Cu/ZnO/Al2O3催化剂

微波介电加热具有高效和节能等特点,近年来利用其独特的“体相加热”效应制备结构特异及性能优越的催化材料在多相催化领域中已引起关注,本文报道微波辐照处理对传统Cu／ZnO／Al2O3催化剂在甲醇水蒸汽重整制氢反应中的促进作用,研究结果表明,微波辐照处理对传统Cu／ZnO／Al2O3催化剂的微结构性质具有调控作用,可大大改善其低温催化活性及制氢选择性。     

丝光沸石骨架中Fe的XAFS表征

通过水热法合成了骨架含铁的杂原子丝光沸石,采用XRD,FT-IR及TPR等表征技术确认铁进入了分子筛骨架。利用XAFS地分子筛中铁的精细结构和配位环境进行了表征和计算,近边吸收的Fe-K边前跃迁证实铁在分子筛骨架中位于四面体配位环境中,与邻近原子存在共价键作用;铁-氧配位键长为0.188～0.189nm.     

超临界条件下合成晶型骨架的介孔氧化锆

采用聚氧乙烯型非离子表面活性剂(PEO)为模板剂,超临界乙醇为介质,在不同条件下(各种PEO,不同pH值和络合剂)合成了类似于MSU的介孔氧化锆.XRD,N₂物理脱吸附曲线,TEM及选区电子衍射证明该介孔氧化锆骨架为四方晶型;改变表面活性剂类型、络合剂及pH可调变介孔氧化锆的BET表面积与孔分布.     

MFI沸石前驱体和硅酸钠共组装制备水热稳定的管状介孔分子筛

在CTAB模板剂的作用下 ,硅酸钠、铝酸钠和含有MFI纳米簇的沸石前躯体溶液通过S+ I-路线共组装得到了高水热稳定的管状形貌介孔分子筛 .XRD结果显示样品具有类似MCM 41的规则排列六方孔道结构 .在沸水中处理 15 0h后 ,介孔特征仍然保留 ,显示出很好的水热稳定性 .综合SEM和TEM的观察结果 ,此介孔分子筛具有中空的管状形貌 ,平均管长2 .0 μm ,平均直径为 0 .3 0 μm .含有MFI纳米簇的沸石前躯体作为硅源的一部分加入体系中 ,MFI纳米簇伴随来自于硅酸钠的可溶性硅物种共同进入分子筛骨架 ,在提高水热稳定性的同时 ,没有降低六方纳米孔道的规整度 ,也没有对分子筛形貌调变带来不利影响 .MFI纳米簇中 ,硅氧四面体和铝氧四面体的紧密联结方式在进入分子筛骨架时得以保留是水热稳定性提高的主要原因 .作为硅源的另一部分加入的硅酸钠 ,使合成体系pH值足够高 (pH >13 ) ,加入H2 SO4调节体系pH值到10 ,管状形貌的介孔分子筛在逐步中和过程中形成 .通过这种特殊的共组装方法合成介孔分子筛 ,在获得中空的管状形貌的同时显著提高水热稳定性 ,为这种管状形貌介孔分子筛的应用奠定了基础 .     

Tris-(2-pyridyl)-pyrazolyl Borate Zinc(II) Complexes: Synthesis,DNA/Protein Binding and In Vitro Cytotoxicity Studies

Zn(II) complexes bearing tris[3-(2-pyridyl)-pyrazolyl] borate (Tp^py) ligand (1–3) was synthesized and examined by spectroscopic and analytical tools. Mononuclear [Tp^pyZnCl] (1) has a Zn(II) centre with one arm (pyrazolyl-pyridyl) dangling outside the coordination sphere which is a novel finding in Tp^pyZn(II) chemistry. In complex [Tp^pyZn(H₂O)][BF₄] (2) hydrogen bonding interaction of aqua moiety stabilizes the dangling arm. In addition, solution state behaviour of complex 1 confirms the tridentate binding mode and reactivity studies show the exogenous axial substituents used to form the [Tp^pyZnN₃] (3). The complexes (1–3) were tested for their ability to bind with Calf thymus (CT) DNA and Bovine serum albumin (BSA) wherein they revealed to exhibit good binding constant values with both the biomolecules in the order of 10⁴–10⁵ M⁻¹. The intercalative binding mode with CT DNA was confirmed from the UV-Visible absorption, viscosity, and ethidium bromide (EB) DNA displacement studies. Further, the complexes were tested for in vitro cytotoxic ability on four triple-negative breast cancer (TNBC) cell lines (MDA-MB-231, MDA-MB-468, HCC1937, and Hs 578T). All three complexes (1–3) exhibited good IC₅₀ values (6.81 to 16.87 μM for 24 h as seen from the MTS assay) results which indicated that these complexes were found to be potential anticancer agents against the TNBC cells.     

蔬果皮的续集——花青素衍生植物颜料的探究

秉持变废为宝的理念，对富含花青素的蔬果皮进行简单处理，获得花青素提取液，再添加白醋或苏打使其变成多彩的植物颜料并作画。在研究过程中发现，紫薯的新鲜度是影响颜料色彩的关键因素之一，新鲜紫薯的颜料色彩偏褐色，而久置紫薯的更鲜艳、明亮。此外，鉴于花青素对酸碱敏感，液体颜料在使用时需先判断纸张的酸碱性。本科普实验生动直观地展示了化学变化，材料简单易得、绿色安全、操作简便，且居家即可实践，有利于激发大众对化学的兴趣与爱好，进而培养学生的动手动脑能力。     

Structural forms of hormone auxins in Madeira vines

X-ray diffraction and small-angle neutron scattering were used to identify the naturally occurring hormone auxin in Madeira vine. Two kinds of auxins belonging to indole-3-acetic acid (IAA, C₁₀H₉NO₂) and 4-chloroindole-3-acetic acid (4-Cl-IAA, C₁₀H₈ClNO₂) have been found. The appearance of well-defined x-ray diffraction peaks from the IAA as well as from the 4-Cl-IAA structures shows that the IAA and 4-Cl-IAA molecules that are produced at the shoot apex crystallize into periodic arrangements, rather than stay in molecular forms, upon transport downward through in stem. Small angle neutron scattering spectra reveal a progressive increase in the length of crystallized IAA and 4-Cl-IAA on transported downward from the shoot apex to the stem, reaching 59 nm in length in the area 8–9 cm below the shoot apex. A portion of IAA loses their carboxyl group COOH becoming inactive in stimulating cell growth, which slows down the growth in an aged stem.