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1.
Rational Design and Application of a Redox‐Active,Photoresponsive, Discrete Metallogelator 下载免费PDF全文
Dr. Rouzbeh Afrasiabi Prof. Dr. Heinz‐Bernhard Kraatz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7695-7700
A photoresponsive discrete metallogelator was rationally designed by incorporating a photochromic azobenzene subunit in the structure of a redox‐active ferrocene–peptide conjugate. The target molecule was purposefully equipped with a dipeptide unit capable of self‐assembly in response to sonication. The designed molecule was shown to undergo supramolecular self‐assembly and achieve organogelation in response to ultrasound, light, heat, and redox signals. The sol–gel phase transition of the designed gelator was found to be sensitive to a plethora of input stimuli, allowing the application of the sol–gel transition behavior in basic logic gate operations. A gel‐based NOT logic gate operation was realized when the redox‐active property of the organogel was examined by using different oxidizing agents. The smart response of the gelator was further exploited in designing XOR operations under oxidizing or non‐oxidizing conditions. 相似文献
2.
Dr. Caroline Clavel Dr. Camille Romuald Emile Brabet Dr. Frédéric Coutrot 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(9):2982-2989
The synthesis of a pH‐sensitive two‐station [1]rotaxane molecular switch by self‐entanglement of a non‐interlocked hermaphrodite molecule, containing an anilinium and triazole moieties, is reported. The anilinium was chosen as the best template for the macrocycle benzometaphenylene[25]crown‐8 (BMP25C8) and allowed the self‐entanglement of the molecule. The equilibrium between the hermaphrodite molecule and the pseudo[1]rotaxane was studied by 1H NMR spectroscopy: the best conditions of self‐entanglement were found in the less polar solvent CD2Cl2 and at high dilution. The triazole moiety was then benzylated to afford a benzyltriazolium moiety, which then played a dual role. On one hand, it acts as a bulky gate to trap the BMP25C8, thus to avoid any self‐disentanglement of the molecular architecture. On another hand, it acts as a second molecular station for the macrocycle. At acidic pH, the BMP25C8 resides around the best anilinium molecular station, displaying the lasso [1]rotaxane in a loosened conformation. The deprotonation of the anilinium molecular station triggers the shuttling of the BMP25C8 around the triazolium moiety, therefore tightening the lasso. 相似文献
3.
Conjugated‐Protein Mimics with Molecularly Imprinted Reconstructible and Transformable Regions that are Assembled Using Space‐Filling Prosthetic Groups 下载免费PDF全文
Prof. Dr. Toshifumi Takeuchi Takuya Mori Atsushi Kuwahara Takeo Ohta Azusa Oshita Dr. Hirobumi Sunayama Dr. Yukiya Kitayama Dr. Tooru Ooya 《Angewandte Chemie (International ed. in English)》2014,53(47):12765-12770
Conjugated‐protein mimics were obtained using a new molecular imprinting strategy combined with post‐imprinting modifications. An antibiotic was employed as a model template molecule, and a polymerizable template molecule was designed, which was composed of the antibiotic and two different prosthetic groups attached through a disulfide bond and Schiff base formation. After co‐polymerization with a cross‐linker, the template molecule was removed together with the prosthetic groups, yielding the apo‐type scaffold. Through conjugation of the two different prosthetic groups at pre‐determined positions within the apo‐type scaffold, the apo cavity was transformed into a functionalized holo cavity, which enables the on/off switching of the molecular recognition ability, signal transduction activity for binding events, and photoresponsive activity. 相似文献
4.
Chun Tang Lijue Chen Longyi Zhang Zhixin Chen Guopeng Li Zhewei Yan Luchun Lin Junyang Liu Longfeng Huang Yiling Ye Yuhui Hua Jia Shi Haiping Xia Wenjing Hong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(31):10711-10715
Molecular components are vital to introduce and manipulate quantum interference (QI) in charge transport through molecular electronic devices. Up to now, the functional molecular units that show QI are mostly found in conventional π‐ and σ‐bond‐based systems; it is thus intriguing to study QI in multicenter bonding systems without both π‐ and σ‐conjugations. Now the presence of QI in multicenter‐bond‐based systems is demonstrated for the first time, through the single‐molecule conductance investigation of carborane junctions. We find that all the three connectivities in carborane frameworks show different levels of destructive QI, which leads to highly suppressed single‐molecule conductance in para‐ and meta‐connected carboranes. The investigation of QI into carboranes provides a promising platform to fabricate molecular electronic devices based on multicenter bonds. 相似文献
5.
Shengxia Li Wei Tang Weimin Zhang Prof. Xiaojun Guo Prof. Qing Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17762-17768
New cross‐linking reagents were synthesized and mixed with polystyrene (PS) in solution to form a blend. Thin‐films were spin‐coated from the blend and then cross‐linked by thermal activation at relatively low temperature (100 °C) to form cross‐linked gate dielectrics. This new method is compatible with plastic substrates in flexible electronics. The azide and alkyne cross‐linking reagents are kinetically stable at room temperature, so any premature cross‐linking is avoided during processing. This method also significantly improved the dielectric performances of PS thin films. Solution‐processed top‐gate organic field‐effect transistor devices with indacenodithiophene–benzothiadiazole copolymer as semiconductor layer and the cross‐linked PS blend as dielectric layer showed improved performances with lower gate leakages and higher operation stabilities than devices with neat PS film as dielectric layer. 相似文献
6.
Jinfeng Ge Lingchao Xie Ruixiang Peng Billy Fanady Jiaming Huang Wei Song Tingting Yan Wenxia Zhang Ziyi Ge 《Angewandte Chemie (International ed. in English)》2020,59(7):2808-2815
Non‐fullerene all‐small‐molecule organic solar cells (NFSM‐OSCs) have shown potential as OSCs, owing to their high purity, easy synthesis and good reproducibility. However, challenges in the modulation of phase separation morphology have limited their development. Herein, two novel small molecular donors, BTEC‐1F and BTEC‐2F, derived from the small molecule DCAO3TBDTT, are synthesized. Using Y6 as the acceptor, devices based on non‐fluorinated DCAO3TBDTT showed an open circuit voltage (Voc) of 0.804 V and a power conversion efficiency (PCE) of 10.64 %. Mono‐fluorinated BTEC‐1F showed an increased Voc of 0.870 V and a PCE of 11.33 %. The fill factor (FF) of di‐fluorinated BTEC‐2F‐based NFSM‐OSC was improved to 72.35 % resulting in a PCE of 13.34 %, which is higher than that of BTEC‐1F (61.35 %) and DCAO3TBDTT (60.95 %). To our knowledge, this is the highest PCE for NFSM‐OSCs. BTEC‐2F had a more compact molecular stacking and a lower crystallinity which enhanced phase separation and carrier transport. 相似文献
7.
Rational Design and Identification of a Non‐Peptidic Aggregation Inhibitor of Amyloid‐β Based on a Pharmacophore Motif Obtained from cyclo[‐Lys‐Leu‐Val‐Phe‐Phe‐] 下载免费PDF全文
Tadamasa Arai Takushi Araya Dr. Daisuke Sasaki Dr. Atsuhiko Taniguchi Dr. Takeshi Sato Dr. Youhei Sohma Prof. Motomu Kanai 《Angewandte Chemie (International ed. in English)》2014,53(31):8236-8239
Inhibition of pathogenic protein aggregation may be an important and straightforward therapeutic strategy for curing amyloid diseases. Small‐molecule aggregation inhibitors of Alzheimer’s amyloid‐β (Aβ) are extremely scarce, however, and are mainly restricted to dye‐ and polyphenol‐type compounds that lack drug‐likeness. Based on the structure‐activity relationship of cyclic Aβ16–20 (cyclo‐[KLVFF]), we identified unique pharmacophore motifs comprising side‐chains of Leu2, Val3, Phe4, and Phe5 residues without involvement of the backbone amide bonds to inhibit Aβ aggregation. This finding allowed us to design non‐peptidic, small‐molecule aggregation inhibitors that possess potent activity. These molecules are the first successful non‐peptidic, small‐molecule aggregation inhibitors of amyloids based on rational molecular design. 相似文献
8.
Dr. Keiichi Katoh Hironari Isshiki Prof. Tadahiro Komeda Prof. Masahiro Yamashita 《化学:亚洲杂志》2012,7(6):1154-1169
Unlike electronics, which is based on the freedom of the charge of an electron whose memory is volatile, spintronics is based on the freedom of the charge, spin, and orbital of an electron whose memory is non‐volatile. Although in most GMR, TMR, and CMR systems, bulk or classical magnets that are composed of transition metals are used, this Focus Review considers the growing use of single‐molecule magnets (SMMs) that are composed of multinuclear metal complexes and nanosized magnets, which exhibit slow magnetic‐relaxation processes and quantum tunneling. Molecular spintronics, which combines spintronics and molecular electronics, is an emerging field of research. Using molecules is advantageous because their electronic and magnetic properties can be manipulated under specific conditions. Herein, recent developments in [LnPc]‐based multiple‐decker SMMs on surfaces for molecular spintronic devices are presented. First, we discuss the strategies for preparing single‐molecular‐memory devices by using SMMs. Next, we focus on the switching of the Kondo signal of [LnPc]‐based multiple‐decker SMMs that are adsorbed onto surfaces, their characterization by using STM and STS, and the relationship between the molecular structure, the electronic structure, and the Kondo resonance of [TbPc2]. Finally, the field‐effect‐transistor (FET) properties of surface‐adsorbed [LnPc2] and [Ln2Pc3] cast films are reported, which is the first step towards controlling SMMs through their spins for applications in single‐molecular memory and spintronics devices. 相似文献
9.
High‐Performance Non‐doped OLEDs with Nearly 100 % Exciton Use and Negligible Efficiency Roll‐Off 下载免费PDF全文
Huijun Liu Jiajie Zeng Jingjing Guo Dr. Han Nie Prof. Zujin Zhao Prof. Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2018,57(30):9290-9294
Non‐doped organic light‐emitting diodes (OLEDs) possess merits of higher stability and easier fabrication than doped devices. However, luminescent materials with high exciton use are generally unsuitable for non‐doped OLEDs because of severe emission quenching and exciton annihilation in neat films. Herein, we wish to report a novel molecular design of integrating aggregation‐induced delayed fluorescence (AIDF) moiety within host materials to explore efficient luminogens for non‐doped OLEDs. By grafting 4‐(phenoxazin‐10‐yl)benzoyl to common host materials, we develop a series of new luminescent materials with prominent AIDF property. Their neat films fluoresce strongly and can fully harvest both singlet and triplet excitons with suppressed exciton annihilation. Non‐doped OLEDs of these AIDF luminogens exhibit excellent luminance (ca. 100000 cd m?2), outstanding external quantum efficiencies (21.4–22.6 %), negligible efficiency roll‐off and improved operational stability. To the best of our knowledge, these are the most efficient non‐doped OLEDs reported so far. This convenient and versatile molecular design is of high significance for the advance of non‐doped OLEDs. 相似文献
10.
Electrically Controlled Eight‐Spin‐Qubit Entangled‐State Generation in a Molecular Break Junction 下载免费PDF全文
Dr. Mausumi Chattopadhyaya Md. Mehboob Alam Dr. Debasis Sarkar Dr. Swapan Chakrabarti 《Chemphyschem》2014,15(9):1747-1751
The generation of spin‐based multi‐qubit entangled states in the presence of an electric field is one of the most challenging tasks in current quantum‐computing research. Such examples are still elusive. By using non‐equilibrium Green′s function‐based quantum‐transport calculations in combination with non‐collinear spin density functional theory, we report that an eight‐spin‐qubit entangled state can be generated with the high‐spin state of a dinuclear Fe(II) complex when the system is placed in a molecular break junction. The possible gate operation scheme, gating time, and decoherence issues have been carefully addressed. Furthermore, our calculations reveal that the preservation of the high spin state of this complex is possible if the experimentalists keep the electric‐field strength below 0.78 V nm?1. In brief, the present study offers a unique way to realize the first example of a multi‐qubit entangled state by electrical means only. 相似文献
11.
Yuuki Komoto Yasuomi Yamazaki Dr. Yusuke Tamaki Madoka Iwane Prof.Dr. Tomoaki Nishino Prof. Dr. Osamu Ishitani Prof. Dr. Manabu Kiguchi Dr. Shintaro Fujii 《化学:亚洲杂志》2018,13(10):1297-1301
Single‐molecule junctions are of particular interest in molecular electronics. To realize molecular electronic devices, it is crucial that functional single‐molecule junctions are connected to each other by using joint units on the atomic scale. However, good joint units have not been reported because controlling the charge transport directions through the junctions is not trivial. Here, we report a joint unit that controls and changes the charge transport directions through the junctions, by using a ruthenium–tris‐bipyridine (RuBpy) complex. The RuBpy single‐molecule junction was fabricated with scanning tunnelling microscopy‐based break junction techniques. The RuBpy single‐molecule junction showed two distinct high and low conductance states. The two states were characterized by the conductance measurement, the correlation analysis, and the comparative experiment of bipyridine (Bpy), which is the ligand unit of RuBpy. We demonstrate that the Ru complex has multiple charge transport paths, where the charge is carried vertically and horizontally through the complex depending on the path. 相似文献
12.
Vratislav Langer Pavel Mach
ubomír Smr
ok Viktor Milata 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(4):o183-o185
The title compound, C12H12FNO3, a potential precursor for fluoroquinoline synthesis, is essentially planar, with the most outlying atoms displaced from the best‐plane fit through all non‐H atoms by 0.163 (2) and 0.118 (2) Å. Molecules are arranged in layers oriented parallel to the (011) plane. The arrangement of the molecules in the structure is controlled mainly by electrostatic interactions, as the dipole moment of the molecule is 5.2 D. In addition, the molecules are linked by a weak C—H...O hydrogen bond which gives rise to chains with the base vector [1,1,1]. Electron transfer within the molecule is analysed using natural bond orbital (NBO) analysis. Deviations from the ideal molecular geometry are explained by the concept of non‐equivalent hybrid orbitals. 相似文献
13.
Dr. Marta Martínez‐Abadía Dr. Gabriella Antonicelli Prof. Dr. Akinori Saeki Prof. Dr. Aurelio Mateo‐Alonso 《Angewandte Chemie (International ed. in English)》2018,57(27):8209-8213
The development of organic electronics requires scalable solution‐processing methods that enable the fabrication of electronic devices over large areas at low cost. The preparation of peropyrene gels constituted of 3D networks of entangled 1D ribbon‐like fibrils that extend over the μm scale are now reported. OFETs were easily fabricated by depositing the gels in the sol state over bottom‐gate bottom‐contact transistors and by allowing its gelation thereafter. Electrical characterisation of such field‐effect transistors shows a good balance between processability and performance with hole mobilities that are two orders of magnitude higher than those observed in thin films obtained from non‐gelating solvents under the same conditions. 相似文献
14.
Takanori Harashima Yusuke Hasegawa Satoshi Kaneko Manabu Kiguchi Tomoya Ono Tomoaki Nishino 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(27):9207-9211
Single‐molecule devices attract much interest in the development of nanoscale electronics. Although a variety of functional single molecules for single‐molecule electronics have been developed, there still remains the need to implement sophisticated functionalization toward practical applications. Given its superior functionality encountered in macroscopic materials, a polymer could be a useful building block in the single‐molecule devices. Therefore, a molecular junction composed of polymer has now been created. Furthermore, an automated algorithm was developed to quantitatively analyze the tunneling current through the junction. Quantitative analysis revealed that the polymer junction exhibits a higher formation probability and longer lifetime than its monomer counterpart. These results suggest that the polymer provides a unique opportunity to design both stable and highly functional molecular devices for nanoelectronics. 相似文献
15.
V. Srinivasa Rao A. B. Samui 《Journal of polymer science. Part A, Polymer chemistry》2009,47(11):2774-2786
Two sets of hyperbranched polyether epoxies were synthesized to study the effect of substituent, rigidity, and nature of photoactive unit on the thermal and photoresponsive properties. Each set was comprised of one molecule with an acyclic moiety in the repeating unit, and two molecules with a cyclic moiety of varying rigidity (cycle size) in the repeating unit. Two substituents on aromatic rings in the repeating unit were present in one set, and other set was without a substituent. The mesogenic and photoresponsive properties were studied and correlated to the varied structural parameters. The effects of varied molecular structural parameters on phase behavior and photoresponsive properties were very prominent. Out of six monomeric diols, only four have exhibited liquid crystalline phase while the polymers corresponding to all monomeric diols revealed mesophase. The findings in photoresponsive properties were further supported by molecular modeling studies. The changes in refractive index, photoviscosity, and fluorescence intensity with irradiation time substantiated the spectral pattern observed in UV‐Vis spectroscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2774–2786, 2009 相似文献
16.
Dr. Zhihai Li Dr. Manuel Smeu Sepideh Afsari Dr. Yangjun Xing Prof. Mark A. Ratner Prof. Eric Borguet 《Angewandte Chemie (International ed. in English)》2014,53(4):1098-1102
Sensors play a significant role in the detection of toxic species and explosives, and in the remote control of chemical processes. In this work, we report a single‐molecule‐based pH switch/sensor that exploits the sensitivity of dye molecules to environmental pH to build metal–molecule–metal (m‐M‐m) devices using the scanning tunneling microscopy (STM) break junction technique. Dyes undergo pH‐induced electronic modulation due to reversible structural transformation between a conjugated and a nonconjugated form, resulting in a change in the HOMO–LUMO gap. The dye‐mediated m‐M‐m devices react to environmental pH with a high on/off ratio (≈100:1) of device conductivity. Density functional theory (DFT) calculations, carried out under the non‐equilibrium Green’s function (NEGF) framework, model charge transport through these molecules in the two possible forms and confirm that the HOMO–LUMO gap of dyes is nearly twice as large in the nonconjugated form as in the conjugated form. 相似文献
17.
Ruiyang Zhao Xuepeng Zhan Liang Yao Qidai Chen Zengqi Xie Yuguang Ma 《Macromolecular rapid communications》2016,37(7):610-615
To fabricate stable photoresponsive films and devices, a cross‐linked network that firmly fixes the position of the chromophores is an ideal structure, because aggregation and/or phase separation effects of chromophores in matrix can be effectively restrained in such robust films. Herein, the in situ electrochemical deposition (ED) of azo‐based precursors containing multielectroactive carbazole units is utilized to construct highly cross‐linked photoresponsive films. 2‐(4‐(9,9‐bis(6‐(9H‐carbazol‐9‐yl)hexyl)‐9H‐fluoren‐2‐yl)phenyl)‐1‐(4‐(9,9‐bis(6‐(9H‐carbazol‐9‐yl)hexyl)‐9H‐fluoren‐7‐yl)phenyl)diazene (BFCzAzo) with high solvability in electrolyte solution, high electroactivity, and highly efficient photoresponsive ability is synthesized by Suzuki coupling reaction as a kind of ED precursor. A highly cross‐linked photoresponsive film is fabricated by ED method using BFCzAzo as ED precursor. The film can be patterned in large area by irradiation with interfering laser beam (355 nm), and the pattern possesses excellent thermal stability and insoluble ability in both organic and inorganic solvents. Excellent reversibility of the nanostructures is demonstrated by irradiation with 550 nm laser beam.
18.
Huiting Fu Zhaohui Wang Yanming Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(14):4488-4499
Over the past few years, non‐fullerene organic solar cells have been a focus of research and their power conversion efficiencies have been improved dramatically from about 6 % to over 14 %. In addition to innovations in non‐fullerene acceptors, the ongoing development of polymer donors has contributed significantly to the rapid progress of non‐fullerene organic solar cell performance. This Minireview highlights the polymer donors that enable high‐performance non‐fullerene organic solar cells. We show the impressive photovoltaic devices results achieved by some of important classes of conjugated polymer systems in non‐fullerene organic solar cells. We discuss the molecular design strategies as far as developing matching polymer donors for non‐fullerene acceptors. We conclude with a brief summary and outlook for advances in donor polymers required for commercialization. 相似文献
19.
Guangjun Tian Dexian Sun Yaogang Zhang Xi Yu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(18):6012-6016
We report an effective modulation of the quantum transport in molecular junctions consisting of aggregation‐induced‐emission(AIE)‐active molecules. Theoretical simulations based on combined density functional theory and rate‐equation method calculations show that the low‐bias conductance of the junction with a single tetraphenylethylene (TPE) molecule can be completely suppressed by strong electron–vibration couplings, that is, the Franck‐Condon blockade effect. It is mainly associated with the low‐energy vibration modes, which is also the origin of the fluorescence quenching of the AIE molecule in solution. We further found that the conductance of the junction can be lifted by restraining the internal motion of the TPE molecule by either methyl substitution on the phenyl group or by aggregation, a mechanism similar to the AIE process. The present work demonstrates the correlation between optical processes of molecules and quantum transport in their junction, and thus opens up a new avenue for the application of AIE‐type molecules in molecular electronics and functional devices. 相似文献
20.
Hierarchical Self‐Assembly in Liquid‐Crystalline Block Copolymers Enabled by Chirality Transfer 下载免费PDF全文
Shuai Huang Yuxuan Chen Shudeng Ma Prof. Dr. Haifeng Yu 《Angewandte Chemie (International ed. in English)》2018,57(38):12524-12528
Helical topological structures are often found in chiral biological systems, but seldom in synthesized polymers. Now, controllable microphase separation of amphiphilic liquid‐crystalline block copolymers (LCBCs) consisting of hydrophilic poly(ethylene oxide) and hydrophobic azobenzene‐containing poly(methylacrylate) is combined with chirality transfer to fabricate helical nanostructures by doping with chiral additives (enantiopure tartaric acid). Through hydrogen‐bonding interactions, chirality is transferred from the dopant to the aggregation, which directs the hierarchical self‐assembly in the composite system. Upon optimized annealing condition, helical structures in film are fabricated by the induced aggregation chirality. The photoresponsive azobenzene mesogens in the LCBC assist photoregulation of the self‐assembled helical morphologies. This allows the construction and non‐contact manipulation of complicated nanostructures. 相似文献