共查询到20条相似文献,搜索用时 15 毫秒
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Imine‐Based Architectures at Surfaces and Interfaces: From Self‐Assembly to Dynamic Covalent Chemistry in 2D 下载免费PDF全文
Iwona Janica Prof. Violetta Patroniak Prof. Paolo Samorì Dr. Artur Ciesielski 《化学:亚洲杂志》2018,13(5):465-481
Within the last two decades, dynamic covalent chemistry (DCC) has emerged as an efficient and versatile strategy for the design and synthesis of complex molecular systems in solution. While early examples of supramolecularly assisted covalent synthesis at surfaces relied strongly on kinetically controlled reactions for post‐assembly covalent modification, the DCC method takes advantage of the reversible nature of bond formation and allows the generation of the new covalently bonded structures under thermodynamic control. These structurally complex architectures obtained by means of DCC protocols offer a wealth of solutions and opportunities in the generation of new complex materials that possess sophisticated properties. In this focus review we examine the formation of covalently bonded imine‐based discrete nanostructures as well as one‐dimensional (1D) polymers and two‐dimensional (2D) covalent organic frameworks (COFs) physisorbed on solid substrates under various experimental conditions, for example, under ultra‐high vacuum (UHV) or at the solid–liquid interface. Scanning tunneling microscopy (STM) was used to gain insight, with a sub‐nanometer resolution, into the structure and properties of those complex nanopatterns. 相似文献
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On-surface chemistry is a promising way to achieve the bottom-up construction of covalently-bonded molecular precursors into extended atomically-precise polymers adsorbed on surfaces. These polymers exhibit unprecedented physical or chemical properties which are of great interest for various potential applications. These nanostructures were mainly obtained in ultra-high vacuum (UHV) on noble metal single-crystal surfaces by thermal annealing as stimulus to provoke the polymerization with a catalytic role of the surface adatoms. Nevertheless, photons are also a powerful source of energy to induce the formation of covalent architectures, even if it is less-used on surfaces than in solution. In this minireview, we discuss the photo-induced on-surface polymerization from the basic mechanisms of photochemistry to the formation of extended polymers on different kinds of surfaces, which are characterized by scanning probe microscopies. 相似文献
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Daan Wouters Dr. Stephanie Hoeppener Dr. Ulrich S. Schubert Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(10):1732-1739
Surfaces with purposes : The electroinitiated patterning of self‐assembled monolayers enables the fabrication of a variety of complex nanostructures (see picture). The possibilities offered by the introduction of chemical selectivity through the local generation of chemically active groups and subsequent derivatization are reviewed, with a focus on progress in this area of research over the last four years.
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Olivier Guillermet Dr. Eeva Niemi Dr. Samuthira Nagarajan Dr. Xavier Bouju Dr. David Martrou Dr. André Gourdon Dr. Sébastien Gauthier Dr. 《Angewandte Chemie (International ed. in English)》2009,48(11):1970-1973
Buckybowls : The adsorption of penta‐tert‐butylcorannulene, a molecule with fivefold symmetry, on Cu(111), a surface with threefold symmetry, is investigated by scanning tunneling microscopy complemented by structure calculations. The symmetry mismatch is resolved by the formation of threefold‐symmetric subunits consisting of three molecules, which combine with single molecules to form a nearly perfect filling of the plane (see picture).
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Chemistry of Anthracene–Acetylene Oligomers XXV: On‐Surface Chirality of a Self‐Assembled Molecular Network of a Fan‐Blade‐Shaped Anthracene–Acetylene Macrocycle with a Long Alkyl Chain 下载免费PDF全文
Dr. Takuya Tsuya Kohei Iritani Dr. Kazukuni Tahara Prof. Yoshito Tobe Dr. Tetsuo Iwanaga Prof. Shinji Toyota 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5520-5527
An anthracene cyclic dimer with two different linkers and a dodecyl group was synthesized by means of coupling reactions. The calculated structure had a planar macrocyclic π core and a linear alkyl chain. Scanning tunneling microscopy observations at the 1‐phenyloctane/graphite interface revealed that the molecules formed a self‐assembled monolayer that consisted of linear striped bright and dark bands. In each domain, the molecular network consisted of either Re or Si molecules that differed in the two‐dimensional chirality about the macrocyclic faces, which led to a unique conglomerate‐type self‐assembly. The molecular packing mode and the conformation of the alkyl chains are discussed in terms of the intermolecular interactions and the interactions between the molecules and the graphite surface with the aid of MM3 simulations of a model system. 相似文献
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Marcin Lindner Dr. Michal Valášek Jan Homberg Kevin Edelmann Dr. Lukas Gerhard Prof. Dr. Wulf Wulfhekel Dr. Olaf Fuhr Tobias Wächter Prof. Dr. Michael Zharnikov Dr. Viliam Kolivoška Dr. Lubomír Pospíšil Dr. Gábor Mészáros Dr. Magdaléna Hromadová Prof. Dr. Marcel Mayor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13218-13235
The efficient synthesis of tripodal platforms based on tetraphenylmethane with three acetyl‐protected thiol groups in either meta or para positions relative to the central sp3 carbon for deposition on Au (111) surfaces is reported. These platforms are intended to provide a vertical arrangement of the substituent in position 4 of the perpendicular phenyl ring and an electronic coupling to the gold substrate. The self‐assembly features of both derivatives are analyzed on Au (111) surfaces by low‐temperature ultra‐high‐vacuum STM, high‐resolution X‐ray photoelectron spectroscopy, near‐edge X‐ray absorption fine structure spectroscopy, and reductive voltammetric desorption studies. These experiments indicated that the meta derivative forms a well‐ordered monolayer, with most of the anchoring groups bound to the surface, whereas the para derivative forms a multilayer film with physically adsorbed adlayers on the chemisorbed para monolayer. Single‐molecule conductance values for both tripodal platforms are obtained through an STM break junction experiment. 相似文献
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Miriam S. Becherer Dipl.‐Chem. Boris Schade Dr. Christoph Böttcher Priv.‐Doz. Dr. Andreas Hirsch Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(7):1637-1648
Shape‐persistent micelles consisting of exactly 12 molecules (see picture), which coexist with rodlike micelles, are formed by the self‐labeled amphicalixarene at pH 7. In contrast to other examples of structurally defined micelles, this new type of amphiphile serves as a fluorescence reporter and provides an extended cavity structure in the hydrophilic part, thereby facilitating the inclusion of guest molecules.
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《Angewandte Chemie (International ed. in English)》2017,56(41):12518-12522
The newly developed oligophenylenevinylene (OPV)‐based fluorescent (FL) chiral chemosensor (OPV‐Me) for the representative enantiomeric guest, 1,2‐cyclohexanedicarboxylic acid (1,2‐CHDA: RR ‐ and SS ‐form) showed the high chiral discrimination ability, resulting in the different aggregation modes of OPV‐Me self‐assembly: RR ‐CHDA directed the fibrous supramolecular aggregate, whereas SS ‐CHDA directed the finite aggregate. The consequent FL intensity toward RR ‐CHDA was up to 30 times larger than that toward SS ‐CHDA. Accordingly, highly enantioselective recognition was achieved. Application to the chirality sensing was also possible: OPV‐Me exhibited a linear relationship between the FL intensity and the enantiomeric excess through the morphological development of stereocomplex aggregates. These results clearly show that the chiral recognition ability is manifested by the amplification cascade of the chirality difference through self‐assembly. 相似文献
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Surface‐Confined Supramolecular Self‐Assembly of Molecular Nanocranes for Chemically Lifting and Positioning C60 above a Conducting Substrate 下载免费PDF全文
Dr. Ping Du Dr. David Kreher Dr. Fabrice Mathevet Dr. Pascale Maldivi Dr. Fabrice Charra Prof. André‐Jean Attias 《Chemphyschem》2015,16(18):3774-3778
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Giuseppina Pace Dr. Artur Stefankiewicz Jack Harrowfield Prof. Jean‐Marie Lehn Prof. Paolo Samorì Prof. 《Chemphyschem》2009,10(4):699-705
On edge : Self‐assembled monolayers of a bis(hydrazone)‐based molecular grid physisorbed on graphite are studied by scanning tunneling microscopy (see picture). High order is attained at the supramolecular level by thermal annealing of the grid‐based films. A preferential edge‐on configuration of the molecular grid with respect to the substrate is found.
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Enantiopure Laterally Functionalized Alleno–Acetylenic Macrocycles: Synthesis,Chiroptical Properties,and Self‐Assembly in Aqueous Media 下载免费PDF全文
Dr. Manolis D. Tzirakis Dr. Mariza N. Alberti Dr. Haim Weissman Prof. Dr. Boris Rybtchinski Prof. Dr. François Diederich 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16070-16073
A family of shape‐persistent alleno–acetylenic macrocycles (SPAAMs), peripherally decorated with structurally diverse pendant groups, has been synthesized and characterized in enantiomerically pure form. Their electronic circular dichroism (ECD) spectra feature a strong chiroptical response, which is more than two times higher than for open‐chain tetrameric analogues. A water‐soluble oligo(ethylene glycol)‐appended SPAAM undergoes self‐assembly in aqueous solution. Morphology studies by cryogenic transmission electron microscopy (cryo‐TEM) revealed the formation of aggregates with fibrous fine structures that correspond to tubular, macrocyclic stacks. 相似文献
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Dr. Christophe Nacci Dr. Andreas Viertel Prof. Dr. Stefan Hecht Prof. Dr. Leonhard Grill 《Angewandte Chemie (International ed. in English)》2016,55(44):13724-13728
The covalent linking of molecular building blocks on surfaces enables the construction of specific molecular nanostructures of well‐defined shape. Molecular nodes linked to various entities play a key role in such networks, but represent a particular challenge because they require a well‐defined arrangement of different building blocks. Herein, we describe the construction of a chemically and geometrically well defined covalent architecture made of one central node and three molecular wires arranged in a nonsymmetrical way and thus encoding different conjugation pathways. Very different architectures of either very limited or rather extended size were obtained depending on the building blocks used for the covalent linking process on the Au(111) surface. Electrical measurements were carried out by pulling individual molecular nodes with the tip of a scanning tunneling microscope. The results of this challenging procedure indicate subtle differences if the nodes are contacted at inequivalent termini. 相似文献
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Torands Revisited: Metal Sequestration and Self‐Assembly of Cyclo‐2,9‐tris‐1,10‐phenanthroline Hexaaza Macrocycles 下载免费PDF全文
Dr. Matthias Georg Schwab Dr. Masayoshi Takase Dr. Alexey Mavrinsky Dr. Wojciech Pisula Prof. Dr. Xinliang Feng Dr. José A. Gámez Prof. Dr. Walter Thiel Dr. Kunal S. Mali Prof. Dr. Steven de Feyter Prof. Dr. Klaus Müllen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(23):8426-8434
A series of novel toroidal cyclo‐2,9‐tris‐1,10‐phenanthroline macrocycles with an unusual hexaaza cavity are reported. Nickel‐mediated Yamamoto aryl–aryl coupling was found to be a versatile tool for the cyclotrimerization of functionalized 1,10‐phenathroline precursors. Due to the now improved processability, both liquid‐crystalline behavior in the bulk phase and two‐dimensional self‐assembly at the molecular level could be studied, for the first time, for a torand system. The macrocycles exhibited a strong affinity for the complexation of different metal cations, as evidenced by MALDI‐TOF analysis and spectroscopic methods. Experimental results were correlated to an extensive computational study of the cyclo‐2,9‐tris‐1,10‐phenanthroline cavity and its binding mode for metal cations. Due to the combination of several interesting features, toroidal macrocycles may find future applications in the field of ion and charge transport through molecular channels, as well as for chemical sensing and molecular writing in surface‐confined monolayers under STM conditions. 相似文献