共查询到20条相似文献,搜索用时 15 毫秒
1.
Shahid A. Soomro 《Tetrahedron》2006,62(34):8089-8094
Two types of dendritic nanoparticles were prepared, which contain (E)-stilbene chromophores in the terminal positions of the dendrons. The compounds showed a highly efficient photoreactivity in the course of which statistical CC bond formations led to a crosslinking of the particles. Finally, all stilbene chromophores reacted and the typical (E)-stilbene absorption and fluorescence disappeared completely. 相似文献
2.
Mathias O. Senge 《Angewandte Chemie (International ed. in English)》1998,37(8):1071-1072
The central core and the macrocycle skeleton of porphyrins both offer room for boron, and a gap in the chemistry of nonmetal-containing porphyrins has now been filled. In one case a four-membered B2O2 ring coordinates to a porphyrin cavity that has been distorted to a rectangle ( A ), and in the other case four boron atoms are located in the meso positions of a tetrathiaporphyrinogen ( B ). 相似文献
3.
4.
Heinrich Lang Bettina Lühmann 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):297-302
This article concentrates on the divergent growth method for the preparation of SiOCH2CH2CH2-based carbosiloxane dendrimers by applying repetitive hydrosilylation-alcoholysis cycles. The silicon atoms thereby act as the branching points producing a tetrahedral four directional core as well as 1→1 and 1→2 branching centres. 相似文献
5.
A convergent synthesis in which all trans double bonds were constructed by Wittig–Horner reactions produces dendrimers of the general structure 1 . With long-chain alkoxy residues on the periphery of the benzene rings, the first two generations display liquid crystalline behavior. 相似文献
6.
Kuan-Jiuh Lin 《Angewandte Chemie (International ed. in English)》1999,38(18):2730-2732
Robust hexagonal cavities (dimensions: 17×20×15 Å), encompassed by the pyridyl groups of cyclic metalloporphyrin hexamers (see picture), are the characteristic structural motifs of the nanoporous materials [{M(tpyp)}6]⋅n G (M=Co, Mn; tpyp=tetrakis(4-pyridyl)porphyrinato; G=guest molecule), which were prepared from MCl2 and H2tpyp under hydrothermal conditions. The rhombohedral crystal lattice with infinite hexagonal channels is thermally stable up to 400°C, even after the removal of the guest molecules. 相似文献
7.
Magdolna Háda Veronika Nagy Gergely Gulyás‐Fekete József Deli Attila Agócs 《Helvetica chimica acta》2010,93(6):1149-1155
For the evaluation of the synthesis of dendritic esters from carotenoids, various carotenols or their succinates were reacted with bi‐ and trifunctional aromatic acids and alcohols. Several methods were tested, from which the Steglich esterification was found to give the best yields. Apocarotenoids showed higher reactivity in most of the reactions and served as model compounds for C40 carotenoids and their derivatives. The synthesized triesters can be regarded as first generation dendrimers. 相似文献
8.
聚酰胺-胺( PAMAM) 树形大分子是近年来得到迅速发展的一类新型聚合物,其独特结构、功能化和应用价值引起了化学家们的极大研究兴趣.并在多个领域显示出良好的应用前景.近来又发现(PAMAM)在适当的pH值条件下发射较强的荧光,本文主要介绍了PAMAM对荧光物质的增强作用,PAMAM作为模板制备纳米粒子中的荧光效应,以及PAMAM自身荧光的发现及对其荧光机理的研究,并对PAMAM的荧光应用进行了展望.PAMAM 树型大分子由于具有良好的生物相容性、优异的能量转移机制等,有可能成为新型的生物荧光标记物. 相似文献
9.
树枝状大分子是一种具有精确三维结构的纳米材料。目前,对于树枝状大分子的研究,逐渐从合成和表征各式各样的树枝状大分子转向到对其特殊功能和应用的研究。传统的荧光成像探针大多数为小分子化合物,其发展受到特异性低、稳定性差、停留时间短、可修饰基团少和毒性大等缺点的限制。树枝状大分子具备独特的分子结构如大量可设计性的末端官能团和广阔的分子内空腔以及选择多样化的优势,使其在荧光生物成像领域中有良好的应用前景。本文重点介绍了基于树枝状大分子的有机荧光探针和量子点探针在生物成像方面最新的研究进展。 相似文献
10.
11.
12.
M. García Martínez B. Alonso C. M. Casado J. Losada M. P. García Armada 《Electroanalysis》2011,23(12):2888-2897
The bioelectrocatalytical properties and kinetic characteristics of new oxidase biosensors based on two different carbosilane dendrimers are described. The best glucose biosensor developed displayed, in an ascorbate interference free work potential interval, a strictly linear range from 0 to 4.0 mM, a detection limit of 40,6 μM and a response time less than 3 s. The lactate biosensor displayed a linear range from 0 to 0.8 mM, a detection limit of 0.73 µM and a response time less than 2 s. The apparent Michaelis–Menten constants were calculated to be 4.39 mM and 2.08 mM respectively, according to Lineweaver–Burk equation. 相似文献
13.
Kiyotaka Onitsuka Masanori Fujimoto Nobuaki Ohshiro Shigetoshi Takahashi 《Angewandte Chemie (International ed. in English)》1999,38(5):689-692
The third‐generation dendrimer with 45 platinum atoms (shown schematically) was synthesized efficiently by a convergent methodology in which two different trialkylsilyl groups (symbolized by the nodal points) are used to protect the bridging triethynylbenzene derivatives. PT=[Pt(PEt3)2]. 相似文献
14.
Yuki Oka Dr. Hiroshi Masai Prof. Dr. Jun Terao 《Angewandte Chemie (International ed. in English)》2023,62(14):e202217002
Catenanes with multistate switchable properties are promising components for next-generation molecular machines and supramolecular materials. Herein, we report a ligand-controlled switching method, a novel method for the multistate switching of catenanes controlled by complexation with added amine ligands. To verify this method, a [3]catenane comprising cyclic porphyrin dimers with a rigid π-system has been synthesized. Owing to the rigidity, the relative positions among the cyclic components of the [3]catenane can be precisely controlled by complexation with various amine ligands. Moreover, ligand-controlled multistate switching affects the optical properties of the [3]catenanes: the emission intensity can be tuned by modulating the sizes and coordination numbers of integrated amine ligands. This work shows the utility of using organic ligands for the structural switching of catenanes, and will contribute to the further development of multistate switchable mechanically interlocked molecules. 相似文献
15.
Anne-Marie Caminade Jean-Pierre Majoral 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1132-1143
AbstractDendrimers are hyperbranched macromolecules constituted of repetitive branched units. They are synthesized step-by-step, a method which ensures a perfectly defined structure. This mini-review reports examples of rare “multiplurifunctionalized” dendrimers that have several types of functional groups precisely located on each terminal branching point. They are obtained thanks to the specificity of the reactivity of each Cl of P(X)Cl2 (X = generally S, but also O) terminal groups on the surface of poly(phosphorhydrazone) dendrimers. 相似文献
16.
17.
A unique combination of a clearly defined particle structure and a very highly functionalized surface is offered by the topical dendrimers. Many groups work on this unusual molecular architecture to develop new applications. The most advanced progress in this respect is an MRI contrast agent based on dendrimers (see schematic representation) that facilitate the visualization of bloodstreams. 相似文献
18.
19.
应用密度泛函理论研究了一系列有机及金属有机苯乙炔树状分子的激发态性质和非线性光学性质。计算的电子吸收光谱显示这些树状分子均在低能区域有一个最强的吸收;此外,金属有机体系的吸收光谱和有机体系相比发生了明显的红移。响应性质的计算结果表明共轭体系的扩展和金属有机基团的引入都使得苯乙炔树状分子的非线性光学极化率显著增加,尤其是含Ru体系,其β和γ值呈数量级增长。对于有机体系和含Pd体系,发生在共轭体系内部的π→π*电荷跃迁是产生分子一阶和二阶超极化率的主要原因。而含Ru体系相当大的非线性响应则主要起源于Ru的轨道到共轭体系的π*的跃迁,同时与Ru相邻的C≡C到共轭体系的π→π*跃迁起着辅助贡献。 相似文献
20.
在树枝(dendron)上引入特定的功能单元,将多个具有特定功能团(咔唑)连接起来.形成功能化树枝状周边分子团簇,然后将它们分别与核心色素萘酰亚胺相连接,合成新型周边树枝状功能化的有机发光材料(共三代)。稳态荧光研究发现周边功能团吸收的能量能以较高的效率传递给中心核色素萘酰亚胺。其传输效率与化合物的树枝代数密切相关,具有特殊的光采集、光放大效应。瞬态荧光研究表明树枝化合物中的咔唑单元都呈双指数衰减特征,其中较短荧光寿命成分是咔唑和萘酰亚胺单元之间的相互作用。 相似文献