共查询到20条相似文献,搜索用时 31 毫秒
1.
Donghak Jang Ho Yong Lee Dr. Miae Park Seong Ryong Nam Dr. Jong‐In Hong Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(16):4836-4842
Two‐component amphiphiles based on hydrogen‐bonded complexes between terephthaloylbisalanine (H2TBA) and dodecylamine (DA) are able to self‐assemble into nano‐ and microsized superstructures in an aqueous solvent. It is possible to modulate the morphology of these self‐assembled superstructures by modifying the composition of the complexes, which can be achieved by changing the molar ratio of the two components or by changing the chirality of H2TBA. For example, right‐handed microhelical ribbon structures were formed with L ‐TBA1.0DA2.0, whereas in the case of rac‐TBA1.0DA2.0, flat ribbonlike structures were observed. Although L ‐TBA1.0DA1.0 exhibited entangled fibrous structures, rac‐TBA1.0DA1.0 exhibited wire structures. Different ratios of H2TBA and DA were self‐assembled into fiber‐, wire‐, and tubulelike superstructures, as well as monoclinic, columnar, and lamellar aggregation patterns. The self‐assembled superstructures of TBAxDAy were significantly changed by adding metal ions. Transition metal (CdII, CoII, and ZnII) complexes with L ‐TBAxDAy self‐assembled into rod‐, tubule‐, wire‐, and platelike superstructures. Metal‐ion complexes with rac‐TBAxDAy exhibited different superstructures. Our work suggests that it is possible to fabricate a wide variety of nano‐ and microsized superstructures by using two‐ and three‐component amphiphiles. 相似文献
2.
Dr. Zhangjun Hu Maria Ahrén Linnéa Selegård Dr. Caroline Skoglund Dr. Fredrik Söderlind Dr. Maria Engström Dr. Xuanjun Zhang Prof. Kajsa Uvdal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(38):12658-12667
Water‐dispersible and luminescent gadolinium oxide (GO) nanoparticles (NPs) were designed and synthesized for potential dual‐modal biological imaging. They were obtained by capping gadolinium oxide nanoparticles with a fluorescent glycol‐based conjugated carboxylate (H L ). The obtained nanoparticles (GO‐ L ) show long‐term colloidal stability and intense blue fluorescence. In addition, L can sensitize the luminescence of europium(III) through the so‐called antenna effect. Thus, to extend the spectral ranges of emission, europium was introduced into L‐ modified gadolinium oxide nanoparticles. The obtained EuIII‐doped particles (Eu:GO‐ L ) can provide visible red emission, which is more intensive than that without L capping. The average diameter of the monodisperse modified oxide cores is about 4 nm. The average hydrodynamic diameter of the L ‐modified nanoparticles was estimated to be about 13 nm. The nanoparticles show effective longitudinal water proton relaxivity. The relaxivity values obtained for GO‐ L and Eu:GO‐ L were r1=6.4 and 6.3 s?1 mM ?1 with r2/r1 ratios close to unity at 1.4 T. Longitudinal proton relaxivities of these nanoparticles are higher than those of positive contrast agents based on gadolinium complexes such as Gd‐DOTA, which are commonly used for clinical magnetic resonance imaging. Moreover, these particles are suitable for cellular imaging and show good biocompatibility. 相似文献
3.
Ping Fang XIA Jianping Lu Chi Ho Kwok Hiroshi Fukutani Man Shing Wong Ye Tao 《Journal of polymer science. Part A, Polymer chemistry》2009,47(1):137-148
Two novel series of monodisperse multi‐triarylamine‐substituted oligothiophenes, G 2 ‐ OT ( n )‐ G 2 with thiophene unit (n) varying from 6 to 8, and 4,7‐bis(2′‐oligothienyl)‐2,1,3‐benzothiadiazoles G 2 ‐ OT ( n ) BTD ‐ G 2 (n = 2, 4, 6) have been synthesized by the Suzuki coupling reactions. With an elongation of alkyl‐substituted oligothiophene core or an incorporation of benzothiadiazole into the central core, the absorption and emission spectra of G 2 ‐ OT ( n )‐ G 2 and G 2 ‐ OT ( n ) BTD ‐ G 2 series red‐shift substantially with the optical gap reducing to 1.95 eV for G 2 ‐ OT ( 6 ) BTD ‐ G 2 . Alkyl‐substitution onto oligothiophene backbone not only improves the solubility of the highly extended dendrimers but also renders coplanarity of the dendritic oligothiophene backbone at the excited state, which results in the enhancement of fluorescence quantum efficiency. The bulk heterojunction solar cells using these newly synthesized dendritic oligothiophenes as a donor material and [6,6]‐phenyl C61‐butyric acid methyl ester (PCBM) as an acceptor material were fabricated and investigated which showed an increase in device performance as compared with those of the lower homologues. On increasing the loading of PCBM from 1.5 to 3 times in the active layer, there was also an enhancement in device performance with power conversion efficiencies of as‐fabricated solar cells increasing from 0.18% to 0.32%. In addition, proper annealing procedure could significantly improve the device performance of the dendrimer‐based photovoltaic cell. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 137–148, 2009 相似文献
4.
A series of Zn2+‐selective two‐photon fluorescent probes (AZnM1−AZnN) that had a wide range of dissociation constants (KdTP=8 nm‐ 12 μM ) were synthesized. These probes showed appreciable water solubility (>3 μM ), cell permeability, high photostability, pH insensitivity at pH>7, significant two‐photon action cross‐sections (86–110 GM) upon complexation with Zn2+, and can detect the Zn2+ ions in HeLa cells and in living tissue slices of rat hippocampal at a depth of >80 μm without mistargeting and photobleaching problems. These probes can potentially find application in the detection of various amounts of Zn2+ ions in live cells and intact tissues. 相似文献
5.
A Bowl‐Shaped Circular Trinuclear Helicate Generated from a TiO4N2 Motif by a Multicomponent Self‐Assembly Approach 下载免费PDF全文
Dr. Pierre Mobian Nathalie Baradel Nathalie Kyritsakas Georges Khalil Prof. Marc Henry 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2435-2441
The synthesis of a bowl‐shaped trinuclear circular titanium‐based helicate is reported. The strategy allowing access to this neutral architecture is based on a multicomponent self‐assembly approach in which the ligands involved in the process are a bis‐biphenol strand and 2,2′‐ bipyrimidine. By reacting the bis‐biphenol ligand and 2,2′‐bipyrimidine with an equimolar amount [Ti(OiPr)4], a bowl‐shaped architecture is obtained through the formation of 18 new coordination bonds. This aggregate built from three octahedral TiO4N2 nodes displays an unusually high stability in solution compared to related species. In addition, by modifying the stoichiometry of the initial components, two assemblies incorporating two titanium centers bridged by a 2,2′‐bipyrimidine ligand are obtained. The crystal structures of these species are reported. 相似文献
6.
Highly Luminescent and Water‐Soluble Two‐Dimensional Supramolecular Organic Framework: All‐Organic Photosensitizer Template for Visible‐Light‐Driven Hydrogen Evolution from Water 下载免费PDF全文
Hyun‐Jun Lee Hyeong‐Ju Kim Eung‐Chang Lee Jaekwan Kim Prof. Soo Young Park 《化学:亚洲杂志》2018,13(4):390-394
A highly fluorescent (ΦF=0.60) and water‐soluble two‐dimensional (2D) honeycomb‐shaped supramolecular organic framework (SOF) was successfully synthesized in pure aqueous solution via self‐assembly of novel cyanostilbene‐functionalized trilateral guest molecules and cucurbit[8]uril hosts. The size of this fluorescent 2D SOF was >500 nm in diameter, 1.7 nm in thickness, and 3.9 nm in the honeycomb pore diameter. This 2D SOF holds potential as a new all‐organic photosensitizer template for photocatalytic H2 evolution from pure water. 相似文献
7.
Guowei Wang Bin Hu Xiaoshan Fan Yannan Zhang Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(11):2227-2235
The tadpole‐shaped copolymers polystyrene (PS)‐b‐[cyclic poly(ethylene oxide) (PEO)] [PS‐b‐(c‐PEO)] contained linear tail chains of PS and cyclic head chains of PEO were synthesized by combination of Glaser coupling with living anionic polymerization (LAP) and ring‐opening polymerization (ROP). First, the functionalized polystyrene‐glycerol (PS‐Gly) with two active hydroxyl groups at ω end was synthesized by LAP of St and the subsequent capping with 1‐ethoxyethyl glycidyl ether and then deprotection of protected hydroxyl group in acid condition. Then, using PS‐Gly as macroinitiator, the ROP of EO was performed using diphenylmethylpotassium as cocatalyst for AB2 star‐shaped copolymers PS‐b‐(PEO‐OH)2, and the alkyne group was introduced onto PEO arm end for PS‐b‐(PEO‐Alkyne)2. Finally, the intramolecular cyclization was performed by Glaser coupling reaction in pyridine/Cu(I)Br/N,N,N′,N″,N″‐pentamethyldiethylenetriamine system under room temperature, and tadpole‐shaped PS‐b‐(c‐PEO) was formed. The target copolymers and their intermediates were well characterized by size‐exclusion chromatography, proton nuclear magnetic resonance spectroscopy, and fourier transform infrared spectroscopy in details. The thermal properties was also determined and compared to investigate the influence of architecture on properties. The results showed that tadpole‐shaped copolymers had lower Tm, Tc, and Xc than that of their precursors of AB2 star‐shaped copolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
8.
Green Synthesis of Red‐Emitting Carbon Nanodots as a Novel “Turn‐on” Nanothermometer in Living Cells 下载免费PDF全文
Dr. Chuanxi Wang Kaili Jiang Qian Wu Jiapeng Wu Prof. Chi Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14475-14479
Temperature measurements in biology and medical diagnostics, along with sensitive temperature probing of living cells, is of great importance; however, it still faces significant challenges. Herein, a novel “turn‐on” carbon‐dot‐based fluorescent nanothermometry device for spatially resolved temperature measurements in living cells is presented. The carbon nanodots (CNDs) are prepared by a green microwave‐assisted method and exhibit red fluorescence (λem=615 nm) with high quantum yields (15 %). Then, an on–off fluorescent probe is prepared for detecting glutathione (GSH) based on aggregation‐induced fluorescence quenching. Interestingly, the quenched fluorescence could be recovered by increasing temperature and the CNDs–GSH mixture could behave as an off–on fluorescent probe for temperature. Thus, red‐emitting CNDs can be utilized for “turn‐on” fluorescent nanothermometry through the fluorescence quenching and recovery processes, respectively. We employ MC3T3‐E1 cells as an example model to demonstrate the red‐emitting CNDs can function as “non‐contact” tools for the accurate measurement of temperature and its gradient inside a living cell. 相似文献
9.
Jaime J. Hernandez Dr. Xiaomin Zhu Dr. Dimitri A. Ivanov Prof. Dr. Martin Möller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(13):4300-4307
A novel wedge‐shaped compound containing two diacetylene tails, namely, methyl 3,5‐bis(trideca‐2,4‐diyn‐1yloxyl)benzoate (DDABM), was synthesized. As shown by UV/Vis spectroscopy this compound can be polymerized under UV irradiation. The crystalline structure of DDABM was investigated by grazing‐incidence wide‐angle X‐ray diffraction on oriented crystalline films deposited on PTFE‐rubbed silicon wafer substrates. Furthermore, the spherulites formed in thicker films were analyzed by wide‐angle X‐ray diffraction. A molecular packing model of DDABM based on the X‐ray diffraction data is proposed. The diacetylene units are oriented along a defined lattice direction with a reticular distance of 4.85 Å, which fulfills the requirements for topochemical polymerization. It was observed that UV polymerization does not affect the phase behavior of the compound, but mainly alters its optical properties. 相似文献
10.
Ayushi Mittal Abhishek K. Singh Anoop Kumar Parmanand Katharina Achazi Rainer Haag Sunil K. Sharma 《先进技术聚合物》2020,31(6):1208-1217
Herein, we report on the synthesis of a new class of novel non‐ionic amphiphiles using triglycerol as a core, which is further functionalized with hydrophilic units poly(ethylene glycol) monomethyl ether (Mn: 350 and 550) and a pair of hydrophobic alkyl chains (C18 or C15) via chemo‐enzymatic approach. Fluorescence measurements and dynamic light scattering studies showed that all of the synthesized amphiphilic systems spontaneously self‐ assemble in aqueous solution, which is further confirmed by the transmission electron microscopy. Encapsulation of hydrophobic moieties like Nile red and nimodipine was studied using ultraviolet‐visible (UV‐vis) and fluorescence spectrometer techniques. A cytotoxicity study of the amphiphiles using A549, HeLa, and MCF7 cell, which showed that all of the synthesized nanocarriers are well tolerated at the concentrations studied. The release profile of encapsulated Nile red in synthesized amphiphilic system was studied in the presence of the immobilized enzyme (Novozym 435). 相似文献
11.
Weian Zhang Li Liu Xiaodong Zhuang Xiaohui Li Jinrui Bai Yu Chen 《Journal of polymer science. Part A, Polymer chemistry》2008,46(21):7049-7061
Aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS) was used to prepare a POSS‐containing reversible addition‐fragmentation transfer (RAFT) agent. The POSS‐containing RAFT agent was used in the RAFT polymerization of N‐isopropylacrylamide (NIPAM) to produce tadpole‐shaped organic/inorganic hybrid Poly(N‐isopropylacrylamide) (PNIPAM). The results show that the POSS‐containing RAFT agent was an effective chain transfer agent in the RAFT polymerization of NIPAM, and the polymerization kinetics were found to be pseudo‐first‐order behavior. The thermal properties of the organic/inorganic hybrid PNIPAM were also characterized by differential scanning calorimetry. The glass transition temperature (Tg) of the tadpole‐shaped inorganic/organic hybrid PNIPAM was enhanced by POSS molecule. The self‐assembly behavior of the tadpole‐shaped inorganic/organic hybrid PNIPAM was investigated by atomic force microscopy and dynamic light scattering. The results show the core‐shell nanostructured micelles with a uniform diameter. The diameter of the micelle increases with the molecular weight of the hybrid PNIPAM. Surprisingly, the micelle of the tadpole‐shaped inorganic/organic hybrid PNIPAM with low molecular weight has a much bigger and more compact core than that with high molecular weight. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7049–7061, 2008 相似文献
12.
Facile Fabrication of Near‐Infrared‐Responsive and Chitosan‐Functionalized Cu2Se Nanoparticles for Cancer Photothermal Therapy 下载免费PDF全文
Photothermal therapy has attracted much interest for use in cancer treatment in recent years. In this study, Cu2Se nanoparticles as a novel photothermal agent modified by chitosan (CS‐Cu2SeNPs) were successfully synthesized through a facile route at room temperature. The as‐synthesized CS‐Cu2SeNPs exhibited good water solubility and significant stability. CS‐Cu2SeNPs can efficiently convert near‐infrared (NIR) light into heat and exhibit excellent thermostability. In vitro experiments showed that CS‐Cu2SeNPs had selective cellular uptake between cancer and normal cells and expressed clear anticancer activity on A375 and HeLa human cancer cells. In addition, the anticancer activity was increased to about 400 % by combination with a laser at 808 nm, which acted through induction of apoptosis with the involvement of intrinsic and extrinsic pathways. CS‐Cu2SeNPs irradiated with a laser effectively triggered the intracellular reactive oxygen species (ROS) overproduction that promoted cell apoptosis. Therefore, the developed CS‐Cu2SeNPs could be used as a novel phototherapeutic agent for the photothermal therapy of human cancers. 相似文献
13.
《化学:亚洲杂志》2017,12(5):561-567
We describe herein the first synthesis of silyl‐ and disilanyl‐BODIPYs through transition‐metal‐catalyzed dehalosilylation of iodo‐BODIPYs using a Pd(P(t Bu)3)2/Et3N/toluene system. Various mono‐ and bis‐silyl‐BODIPYs, mono‐ and bis‐disilanyl‐BODIPYs and bis‐BODIPYs linked by silylene and SiOSi groups were synthesized by using this straightforward method. Silyl‐ and disilanyl‐substitution significantly modifies the spectroscopic properties of the BODIPY, in which the fluorescence quantum yields of the silyl‐BODIPYs are remarkably increased, whereas the emission spectra of disilanyl‐BODIPYs are red‐shifted due to effective σ(SiSi)–π(BODIPY) conjugation. 相似文献
14.
Haichang Zhang Erqian Guo Xueheng Zhang Wenjun Yang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):463-470
The synthesis, one‐ and two‐photon absorption (TPA) and emission properties of two novel 2,6‐anthracenevinylene‐based copolymers, poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinylene‐alt‐N‐octyl‐3,6‐carbazolevinyl‐ene] ( P1 ) and poly[9,10‐bis(3,4‐bis(2‐ethylhexyloxy)phenyl)‐2,6‐anthracenevinyl‐ene‐alt‐N‐octyl‐2,7‐carbazolevinylene] ( P2 ) were reported. The as‐synthesized polymers have the number‐average molecular weights of 1.56 × 104 for P1 and 1.85 × 104 g mol?1 for P2 and are readily soluble in common organic solvents. They emit strong bluish‐green one‐ and two‐photon excitation fluorescence in dilute toluene solution (? P1 = 0.85, ? P2 = 0.78, λem( P1 ) = 491 nm, λem( P2 ) = 483 nm). The maximal TPA cross‐sections of P1 and P2 measured by the two‐photon‐induced fluorescence method using femtosecond laser pulses in toluene are 840 and 490 GM per repeating unit, respectively, which are obviously larger than that (210 GM) of poly[9,10‐bis‐(3,4‐bis(2‐ethylhexyloxy) phenyl)‐2,6‐anthracenevinylene], indicating that the poly(2,6‐anthracenevinylene) derivatives with large TPA cross‐sections can be obtained by inserting electron‐donating moieties into the polymer backbone. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 463–470, 2010 相似文献
15.
Mengyi Xiong Zhenglin Yang Ryan J. Lake Junjie Li Shanni Hong Huanhuan Fan Xiao‐Bing Zhang Yi Lu 《Angewandte Chemie (International ed. in English)》2020,59(5):1891-1896
Genetically encoded fluorescent proteins (FPs) have been used for metal ion detection. However, their applications are restricted to a limited number of metal ions owing to the lack of available metal‐binding proteins or peptides that can be fused to FPs and the difficulty in transforming the binding of metal ions into a change of fluorescent signal. We report herein the use of Mg2+‐specific 10–23 or Zn2+‐specific 8–17 RNA‐cleaving DNAzymes to regulate the expression of FPs as a new class of ratiometric fluorescent sensors for metal ions. Specifically, we demonstrate the use of DNAzymes to suppress the expression of Clover2, a variant of the green FP (GFP), by cleaving the mRNA of Clover2, while the expression of Ruby2, a mutant of the red FP (RFP), is not affected. The Mg2+ or Zn2+ in HeLa cells can be detected using both confocal imaging and flow cytometry. Since a wide variety of metal‐specific DNAzymes can be obtained, this method can likely be applied to imaging many other metal ions, expanding the range of the current genetically encoded fluorescent protein‐based sensors. 相似文献
16.
Shape‐Memory Platinum(II) Complexes: Intelligent Vapor‐History Sensor with ON–OFF Switching Function 下载免费PDF全文
Yasuhiro Shigeta Dr. Atsushi Kobayashi Dr. Tadashi Ohba Dr. Masaki Yoshida Dr. Takeshi Matsumoto Prof. Ho‐Chol Chang Prof. Masako Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(8):2682-2690
A novel platinum(II)–diimine complex, [Pt(CN)2(H2dcphen)] ( 1 ; H2dcphen=4,7‐dicarboxy‐1,10‐ phenanthroline), was synthesized and its vapochromic shape‐memory behavior was evaluated. The as‐synthesized amorphous purple solid, [Pt(CN)2(H2dcphen)]?2 H2O ( 1 P ), exhibited vapochromic behavior in the presence of alcoholic vapors through transformation to a red, crystalline, porous, vapor‐adsorbed form, 1 R?vapor . The obtained 1 R?vapor complex released the adsorbed vapors upon heating without collapse of the porous structure. The vaporfree, porous 1 R?open could detect water or n‐hexane vapor, although these vapors could not induce 1 P ‐to‐ 1 R?vapor transformation, and 1 R?open could easily be converted to the initial 1 P by manual grinding. These results indicate that 1 is a new shape‐memory material that functions through formation and collapse of the porous framework with an emission change upon vapor‐adsorption and grinding; this enables it to exhibit vapor history and ON–OFF switching sensing functions. 相似文献
17.
Madathumpady Abubaker Habeeb Muhammed Pramod Kumar Verma Samir Kumar Pal Dr. R. C. Arun Kumar Soumya Paul Ramakrishnapillai Vyomakesannair Omkumar Dr. Thalappil Pradeep Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(39):10110-10120
A novel interfacial route has been developed for the synthesis of a bright‐red‐emitting new subnanocluster, Au23, by the core etching of a widely explored and more stable cluster, Au25SG18 (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au22 and Au33. Whereas Au22 and Au23 are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au33 is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au23 exhibits quenching of fluorescence selectively in the presence of Cu2+ ions and it can therefore be used as a metal‐ion sensor. Aqueous‐ to organic‐phase transfer of Au23 has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au23 before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au23 emission has been demonstrated. The inherent fluorescence of Au23 was used for imaging human hepatoma cells by employing the avidin–biotin interaction. 相似文献
18.
Water‐Soluble Triarylborane Chromophores for One‐ and Two‐Photon Excited Fluorescence Imaging of Mitochondria in Cells 下载免费PDF全文
Stefanie Griesbeck Dr. Zuolun Zhang Marcus Gutmann Dr. Tessa Lühmann Dr. Robert M. Edkins Guillaume Clermont Dr. Adina N. Lazar Dr. Martin Haehnel Dr. Katharina Edkins Antonius Eichhorn Dr. Mireille Blanchard‐Desce Prof. Dr. Lorenz Meinel Prof. Dr. Todd B. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14701-14706
Three water‐soluble tetracationic quadrupolar chromophores comprising two three‐coordinate boron π‐acceptor groups bridged by thiophene‐containing moieties were synthesised for biological imaging applications. Compound 3 containing the bulkier 5‐(3,5‐Me2C6H2)‐2,2′‐(C4H2S)2‐5′‐(3,5‐Me2C6H2) bridge is stable over a long period of time, exhibits a high fluorescence quantum yield and strong one‐ and two‐photon absorption (TPA), and has a TPA cross section of 268 GM at 800 nm in water. Confocal laser scanning fluorescence microscopy studies in live cells indicated localisation of the chromophore at the mitochondria; moreover, cytotoxicity measurements proved biocompatibility. Thus, chromophore 3 has excellent potential for one‐ and two‐photon‐excited fluorescence imaging of mitochondrial function in cells. 相似文献
19.
A DNA–Fullerene Conjugate as a Template for Supramolecular Chromophore Assemblies: Towards DNA‐Based Solar Cells 下载免费PDF全文
Dipl.‐Chem. Philipp Ensslen M. Sc. Stefan Gärtner Dipl.‐Phys. Konstantin Glaser Dr. Alexander Colsmann Prof. Dr. Hans‐Achim Wagenknecht 《Angewandte Chemie (International ed. in English)》2016,55(5):1904-1908
A fullerene was covalently attached to a (dA)20 template that serves as structural scaffold to self‐assemble an ordered and mixed array of ethynyl‐pyrene‐ and ethynyl‐Nile‐red‐nucleoside conjugates. Fluorescence spectroscopy revealed evidence for energy transfer between the two different chromophores. Moreover, fluorescence quenching is significantly enhanced by the attached fullerene in mixed assemblies of different chromophore ratios. This indicates exciton dissociation by electron transfer from the photo‐generated exciton on the chromophore stack to the fullerene. The fullerene–DNA‐conjugate was integrated as a photo‐active layer in solar cells that showed charge‐carrier generation in the spectral regime of all three components of the conjugate. This work clearly demonstrates that DNA is suitable as structural element for chromophore assemblies in future organic optoelectronic devices, such as solar cells. 相似文献
20.
The ring‐opening polymerization of (R,S)‐β‐butyrolactone (BL) in bulk was analyzed with respect to the polymer structure of the resulting poly[(R,S)‐3‐hydroxybutanoate)] [P(3HB)] by isolation of the pure form using preparative supercritical CO2 fluid chromatography. It was confirmed that the four‐membered BL was polymerized in bulk by lipase to yield the corresponding cyclic, hydroxy‐ and crotonate‐terminated P(3HB)s. The relative ratios of the three types of polymers depended on the lipase concentration as well as on the monomer conversion. It was also confirmed that both cyclic and linear P(3HB) polymer species were subject to hydrolysis, and inter‐ and intramolecular transesterification by lipase to produce two series of polymers having linear and cyclic structures with higher and lower molecular weight. The formation of the cyclic P(3HB) iss regarded as the characteristic feature of the lipase‐catalyzed polymerization of BL. 相似文献