腺嘌呤取代锌卟啉配合物的自组装研究

合成了一种新型的带有腺嘌呤取代基的锌卟啉并对其进行了表征。结果表明,腺嘌呤取代基与中心金属锌的轴向配位驱动了自组装。分子量的测量及紫外可见和荧光光谱表明,存在由自组装而产生的卟啉低聚物。     

双亲性稠环双卟啉的合成和自组装研究

在稠环双卟啉分子两侧的卟啉环上分别连接亲水和疏水性取代基,合成双亲性稠环双卟啉分子。利用紫外-可见光谱和核磁氢谱考察了它们在不同溶剂中的溶解行为。结果表明,当双卟啉环两侧取代基的亲疏水性差异足够大时,在亲水性溶剂中,两侧取代基溶解性的差异所提供的附加亲疏水作用,可以引导稠环双卟啉分子通过π-π堆积作用形成H-聚集体。这种自组装形成的一维柱状超分子聚集体,在分子光电器件等领域具有潜在的应用前景。     

不同类型卟啉自组装膜的制备及表征

制备了不同类型的巯基卟啉自组装膜,借助多种表征技术（紫外可见光谱、电化学和X射线光电子能谱）研究了不同类型卟啉自组装膜的结构特点;研究结果表明,卟啉分子中巯基取代基数目的不同（-[SH]n-,n=1,4）,导致了卟啉环在自组装膜表面的构型不同,从而表现出不同巯基卟啉自组装膜性能的差异。 在此基础上,提出了不同巯基卟啉自组装膜的结构模型。     

系列巯基苯基卟啉自组装膜的光谱和电化学性质

考察了系列巯基苯基卟啉自组装膜的光谱及电化学特征。 结果表明,与溶液中巯基苯基卟啉的光谱相比,自组装膜中卟啉分子的吸收和荧光光谱均发生了明显变化,随着卟啉分子中巯基数目的增加,其荧光峰依次发生红移;不同巯基苯基卟啉自组装膜修饰电极对电解液中电对的电子转移阻碍能力不同,由5,10-二[4-(3-巯基丙氧基)-苯基]-15,20二苯基卟啉形成的卟啉自组装膜的阻碍作用最强,膜表面覆盖度最致密。     

不对称酰胺基二茂铁卟啉的合成及其性能研究

合成了两种不对称酰胺基二茂铁卟啉化合物,利用质谱、核磁共振氢谱、紫外光谱和红外光谱等方法表征了其结构,并讨论了酰胺基二茂铁卟啉的荧光,电化学,拉曼光谱的影响和变化规律。光谱和电化学的研究表明,取代基(CH_3O)使酰胺基二茂铁卟啉发射光谱红移,荧光量子产率增大,对于拉曼光谱的苯环振动有很大的影响;电化学结果显示使卟啉更易失电子被氧化。研究结果表明通过改变卟啉周边的取代基可以调控二茂铁卟啉的光谱和电化学性能.     

反丁烯二酰基桥连的带不同取代基的卟啉二联体的合成与性质

合成了反丁烯二酰基桥连的3种带不同取代基的卟啉二联体, 通过红外光谱, 紫外-可见光谱, 核磁共振波谱和质谱对化合物的结构进行了确认, 并研究了二联体的表面光电压谱, 荧光光谱和激光拉曼光谱的变化. 结果表明, 取代基的类型对卟啉二联体分子的荧光量子产率有显著影响, 带供电子基团的甲氧基增强了荧光量子产率, 而带吸电子基团的氯则降低了荧光量子产率, 并且吸电子基团的氯比供电子基团的甲氧基对荧光的影响更大. 取代基的电子效应对卟啉二联体的荧光性和激光拉曼光谱有较大影响.     

氯代苯基卟啉-5-氟尿嘧啶化合物的光谱研究

合成了12种新型卟啉－5－氟尿嘧啶化合物,通过核磁共振谱,质谱,红外光谱,紫外光谱,荧光光谱及元素分析确定了其结构,并讨论了和总结了12种化合物光谱的关系特征及其规律,确定配体与5－氟尿嘧啶相连点是N1－H还是N2－H的判据。卟啉环上苯的1HNMR峰形受取代基氯原子位置影响较大,且化学位移向低场移动,不受卟啉链长短的影响。12种化合物的荧光强度都遵循双取代化合物高于单取代化合物的规律。     

不对称中位取代卟啉类化合物的研究进展

卟啉类化合物不仅在自然界中广泛存在,而且在分子自组装、生物仿生、电化学、分析化学、催化化学等诸多领域都具有广泛的应用。卟啉因中位取代基的种类、数量和性质不同,所表现出来的化学性质也不相同,因此引起了有机工作者的广泛关注。本文首先简单地介绍了卟啉类化合物的基本结构特点和物理、化学性质;然后以结构相对简单的四苯基卟啉为对象,讨论了其合成反应机理;接着重点阐述了不对称中位取代卟啉的3种合成方法,即混合缩合法、全合成法和功能化预先形成法;最后对近年来国内外关于卟啉类化合物的研究状况进行了总结,并对其广阔的发展和应用前景进行展望。     

[T（P—NO2）PP]Fe（Ⅱ）（NO）配合物的制备与光谱性质研究

70年代以来,金属卟啉无机小分子配合物日益受到重视。NO可以与金属卟啉形成配合物,并且自身被活化。目前关于原卟啉Ⅸ二甲酯铁、四苯基卟啉铁和八乙基卟啉铁的NO配合物研究已有一些报道,但有取代基的四苯基卟啉体系研究甚少。为深入考察不同取代基活化NO的规律,我们合成了五配位的四(对-硝基苯基)卟啉铁-氧化氮配合物[简称[T(p-NO_2)PP]Fe(Ⅱ)(NO)],并研究了它的光谱性质。     

新颖的5,15-二(4-(5-乙酰基硫戊氧基)苯基)卟啉化合物的结构和性质的密度泛函理论计算

通过密度泛函理论计算比较性地研究了5,15-二(4-(5-乙酰基硫戊氧基)苯基)自由卟啉及其锌配合物的分子结构、电荷性质、分子轨道、电子吸收光谱和红外光谱.这类化合物具有在卟啉相对的两个中位的苯环上连有5-乙酰基硫戊氧基的新颖结构.模拟得到的这两个化合物的分子结构和电子吸收光谱以及红外光谱都与实验测得的符合得很好.通过与未取代的自由卟啉和卟啉锌的结构和性质进行比较,研究了中位取代基、极性溶剂和中心金属取代对此类卟啉化合物结构和性质的影响规律.对化合物的电子吸收光谱中的电子跃迁本质进行了归属,并通过基于正则坐标分析产生的动画对红外光谱的振动模式进行了指认.目前的工作将对理解此类新颖卟啉化合物的结构和性质以及取代基和溶剂效应提供很大的帮助.     

A Binuclear Zinc Interaction Fold Discovered in the Homodimer of Alzheimer's Amyloid‐β Fragment with Taiwanese Mutation D7H

Zinc‐induced oligomerization of amyloid‐β peptide (Aβ) produces potentially pathogenic agents of Alzheimer's disease. Mutations and modifications in the metal binding domain 1–16 of Aβ peptide crucially affect its zinc‐induced oligomerization by changing intermolecular zinc mediated interface. The 3D structure of this interface appearing in a range of Aβ species is a prospective drug target for disease modifying therapy. Using NMR spectroscopy, EXAFS spectroscopy, mass spectrometry, and isothermal titration calorimetry the interaction of zinc ions with Aβ fragments 1–7 and 1–10 carrying familial Taiwanese mutation D7H was studied. Zinc ions induce formation of a stable homodimer formed by the two peptide chains fastened by two zinc ions and stacking interactions of imidazole rings. A binuclear zinc interaction fold in the dimer structure was discovered. It can be used for designing zinc‐regulated proteins and zinc‐mediated self‐assembling peptides.     

Fluorescent Cross‐Linked Supramolecular Polymer Constructed by Orthogonal Self‐Assembly of Metal–Ligand Coordination and Host–Guest Interaction

A new host molecule consists of four terpyridine groups as the binding sites with zinc(II) ion and a copillar[5]arene incorporated in the center as a spacer to interact with guest molecule was designed and synthesized. Due to the 120 ° angle of the rigid aromatic segment, a cross‐linked dimeric hexagonal supramolecular polymer was therefore generated as the result of the orthogonal self‐assembly of metal–ligand coordination and host–guest interaction. UV/Vis spectroscopy, ¹H NMR spectroscopy, viscosity and dynamic light‐scattering techniques were employed to characterize and understand the cross‐linking process with the introduction of zinc(II) ion and guest molecule. More importantly, well‐defined morphology of the self‐assembled supramolecular structure can be tuned by altering the adding sequence of the two components, that is, the zinc(II) ion and the guest molecule. In addition, introduction of a competitive ligand suggested the dynamic nature of the supramolecular structure.     

Oligothiophene Self‐Assembly on the Surface of ZnO Nanorods: Toward Coaxial p–n Hybrid Heterojunctions

We describe herein the design, synthesis and detailed structural characterization of hybrid 1D nanostructures. They are prepared by supramolecular self‐assembly of oligothiophene molecules on the surface of zinc oxide nanorods in solution at room temperature. Electronic absorption spectroscopy and X‐ray diffraction show that both organic and inorganic components in the coaxial p–n heterojunctions are crystalline. Especially, it is demonstrated that the organic compounds form a self‐assembled monolayer at the surface of the nanorods, which is not the case when zinc oxide quantum dots are instead used. As a result of their hybrid nature, the 1D nanostructures lead to ambipolar semiconducting nanostructured materials as active layers in field‐effect transistors.     

Bending Nanofibers into Nanospirals: Coordination Chemistry as a Tool for Shaping Hydrophobic Assemblies

In the current work, we demonstrate how coordination chemistry can be employed to direct self‐assembly based on strong hydrophobic interactions. To investigate the influence of coordination sphere geometry on aqueous self‐assembly, we synthesized complexes of the amphiphilic perylene diimide terpyridine ligand with the first‐row transition‐metal centers (zinc, cobalt, and nickel). In aqueous medium, aggregation of these complexes is induced by hydrophobic interactions between the ligands. However, the final shapes of the resulting assemblies depend on the preferred geometry of the coordination spheres typical for the particular metal center. The self‐assembly process was characterized by UV/Vis spectroscopy, zeta potential measurements, and cryogenic transmission electron microscopy (cryo‐TEM). Coordination of zinc(II) and cobalt(II) leads to the formation of unique nanospiral assemblies, whereas complexation of nickel(II) leads to the formation of straight nanofibers. Notably, coordination bonds are utilized not as connectors between elementary building blocks, but as directing interactions, enabling control over supramolecular geometry.     

磷酸溶液中DDA在锌表面的吸附及其缓蚀作用

采用失重法及电化学法研究了锌在含或不含十二烷基胺（DDA）的磷酸溶液中的腐蚀作用，得出相应的动力学方程，求得有关的动力学及热力学参数.用光电子能谱（XPS）检测发现，在40～70 ℃区间，锌在磷酸溶液中生成Zn(OH)x覆盖层，表现出较强的自缓蚀效果，而在30～40 ℃区间，因DDA以及, 等微粒同时吸附在锌表面，DDA在磷酸溶液中表现出较强的缓蚀作用.用吸附理论讨论了这种缓蚀作用产生的原因.     

某航空橡胶密封材料成分分析

采用红外光谱法对某航空橡胶密封材料成分进行定性分析,结果表明,该样品的胶种为硫化甲基硅橡胶,有机助剂为邻苯二甲酸二辛酯(DOP),无机灰分为氧化锌、硫酸钙,含量为4%。使用红外光谱法分析航空密封橡胶成分是一种经济且快速的分析方法。     

酶催化动力学光度法测定锌

近年来酶法在分析测定方面的研究非常活跃,酶法测定锌已有报道,基本为终点测定法。本文中的研究是基于LDH催化下列反应：丙酮酸＋NADH=乳酸＋NAD^＋（氧化型烟酰胺腺嘌呤二核苷酸）,锌离子的存在对酶催化反应具有抑制作用,反应速度的变化率与锌离子的浓度呈相关关系,从而可测定试样中的锌离子含量。本方法不需要底物转变完全,与终点测定法相比,可减少测定时间并节省酶量。     

Rectification in Supramolecular Zinc Porphyrin/Fulleropyrrolidine Dyads Self‐Organized on Gold(111)

Self‐assembled donor/acceptor dyads are of current interest as they are biomimetic to the natural photosynthetic conversion system. Herein, we present an ultrahigh‐vacuum scanning tunneling microscopy and scanning tunneling spectroscopy (UHV‐STM/STS) study of ex situ self‐assembled supramolecular dyads consisting of fulleropyrrolidines (PyC₂C₆₀) axially ligated to zinc(II) tetraphenylporphyrin (ZnTPP), self organized on a 4‐aminothiophenol (4‐ATP) self‐assembled monolayer on gold(111). These dyads show both bias‐polarity‐dependent apparent height in STM images and highly rectifying behavior in tunneling spectroscopy. First‐principles density functional theory calculations clarify the conformational and electronic properties of the 4‐ATP/ZnTPP/PyC₂C₆₀ system. Interestingly, we find easier tunneling for electrons moving from the acceptor side of the dyads to the donor side, in the inverse‐rectifying sense with respect to previously reported molecular rectifiers. Such behavior cannot be explained as an elastic resonant tunneling process, but it can by using a model based on the Aviram–Ratner mechanism.