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1.
Ryo Kimura Hikaru Kuramochi Pengpeng Liu Takuya Yamakado Atsuhiro Osuka Tahei Tahara Shohei Saito 《Angewandte Chemie (International ed. in English)》2020,59(38):16430-16435
Flapping fluorophores (FLAP) with a flexible 8π ring are rapidly gaining attention as a versatile photofunctional system. Here we report a highly photostable “flapping peryleneimide” with an unprecedented fluorogenic mechanism based on a bent‐to‐planar conformational change in the S1 excited state. The S1 planarization induces an electronic configurational switch, almost quenching the inherent fluorescence (FL) of the peryleneimide moieties. However, the FL quantum yield is remarkably improved with a prolonged lifetime upon a slight environmental change. This fluorogenic function is realized by sensitive π‐conjugation design, as a more π‐expanded analogue does not show the planarization dynamics. With strong visible‐light absorption, the FL lifetime response synchronized with the flexible flapping motion is useful for the latest optical techniques such as FL lifetime imaging microscopy (FLIM). 相似文献
2.
Orsolya Demeter Eszter A. Fodor Prof. Dr. Mihály Kállay Prof. Dr. Gábor Mező Dr. Krisztina Németh Dr. Pál T. Szabó Dr. Péter Kele 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(18):6382-6388
Herein, we give the very first example for the development of a fluorogenic molecular probe that combines the two‐point binding specificity of biarsenical‐based dyes with the robustness of bioorthogonal click‐chemistry. This proof‐of‐principle study reports on the synthesis and fluorogenic characterization of a new, double‐quenched, bis‐azide fluorogenic probe suitable for bioorthogonal two‐point tagging of small peptide tags by double strain‐promoted azide–alkyne cycloaddition. The presented probe exhibits remarkable increase in fluorescence intensity when reacted with bis‐cyclooctynylated peptide sequences, which could also serve as possible self‐labeling small peptide tag motifs. 相似文献
3.
Martin Olschewski Stephan Knop Dr. Jörg Lindner Prof. Dr. Peter Vöhringer 《Angewandte Chemie (International ed. in English)》2013,52(37):9634-9654
It is fair to say that if we ever wish to understand the anomalous properties of water, we need to study hydrogen bonds. Such a statement is based on statistical mechanics, which tells us how to calculate the structure and the thermodynamic properties of fluids and dense liquids from the forces between the particles. However, in the case of complex associated liquids, such calculations present a formidable—if not even insurmountable—challenge, which largely reflects our still‐limited understanding of the hydrogen‐bonding phenomenon itself. More experimental research on hydrogen‐bonded systems is required to develop a comprehensive, satisfactory theory for associated liquids. This Review gives an introduction to the latest experimental technique currently being used to study the ultrafast structural dynamics of hydrogen bonds, namely two‐dimensional infrared spectroscopy, and its applications to hydrogen‐bonded systems of systematically increasing complexity, starting from the single hydrogen bond of a diol to low‐dimensional extended networks of stereoselectively synthesized polyalcohols. 相似文献
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o‐Fluorination of Aromatic Azides Yields Improved Azido‐Based Fluorescent Probes for Hydrogen Sulfide: Synthesis,Spectra, and Bioimaging
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Chao Wei Runyu Wang Dr. Lv Wei Longhuai Cheng Zhifei Li Prof. Dr. Zhen Xi Prof. Dr. Long Yi 《化学:亚洲杂志》2014,9(12):3586-3592
Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with multiple biological functions. To visualize the endogenous in situ production of H2S in real time, new coumarin‐ and boron‐dipyrromethene‐based fluorescent turn‐on probes were developed for fast sensing of H2S in aqueous buffer and in living cells. Introduction of a fluoro group in the ortho position of the aromatic azide can lead to a greater than twofold increase in the rate of reaction with H2S. On the basis of o‐fluorinated aromatic azides, fluorescent probes with high sensitivity and selectivity toward H2S over other biologically relevant species were designed and synthesized. The probes can be used to in situ to visualize exogenous H2S and D ‐cysteine‐dependent endogenously produced H2S in living cells, which makes them promising tools for potential applications in H2S biology. 相似文献
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Dr. Hua Lu Dr. Soji Shimizu Dr. John Mack Prof. Zhen Shen Prof. Nagao Kobayashi 《化学:亚洲杂志》2011,6(4):1026-1037
A series of fused‐ring‐expanded aza‐boradiazaindacene (aza‐BODIPY) dyes have been synthesized by reacting arylmagnesium bromides with phthalonitriles or naphthalenedicarbonitriles. An analysis of the structure–property relationships has been carried out based on X‐ray crystallography, optical spectroscopy, and theoretical calculations. Benzo and 1,2‐naphtho‐fused 3,5‐diaryl aza‐BODIPY dyes display markedly red shifted absorption and emission bands in the near‐IR region (>700 nm) due to changes in the energies of the frontier MOs relative to those of 1,3,5,7‐tetraaryl aza‐BODIPYs. Only one 1,2‐naphtho‐fused aza‐BODIPY of the three possible isomers is formed due to steric effects, and 2,3‐naphtho‐fused compounds could not be characterized because the final BF2 complexes are unstable in solution. The incorporation of a N(CH3)2 group at the para‐positions of a benzo‐fused 3,5‐diaryl aza‐BODIPY quenches the fluorescence in polar solvents and results in a ratiometric pH response, which could be used in future practical applications as an NIR “turn‐on” fluorescence sensor. 相似文献
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Jonas Fölling Vladimir Belov Dr. D. Riedel Dr. Andreas Schönle Dr. Alexander Egner Dr. Christian Eggeling Dr. Mariano Bossi Dr. Stefan W. Hell Prof. Dr. 《Chemphyschem》2008,9(2):321-326
During the last decade far‐field fluorescence microscopy methods have evolved that have resolution far below the wavelength of light. To outperform the limiting role of diffraction, all these methods, in one way or another, switch the ability of a molecule to emit fluorescence. Here we present a novel rhodamine amide that can be photoswitched from a nonfluorescent to a fluorescent state by absorption of one or two photons from a continuous‐wave laser beam. This bright marker enables strict control of on/off switching and provides single‐molecule localization precision down to 15 nm in the focal plane. Two‐photon induced nonlinear photoswitching of this marker with continuous‐wave illumination offers optical sectioning with simple laser equipment. Future synthesis of similar compounds holds great promise for cost‐effective fluorescence nanoscopy with noninvasive optical sectioning. 相似文献
9.
Yan‐Wei Wang Ana B. Descalzo Dr. Zhen Shen Prof. Xiao‐Zeng You Prof. Knut Rurack Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(9):2887-2903
A new series of boron–dipyrromethene (BDP, BODIPY) dyes with dihydronaphthalene units fused to the β‐pyrrole positions ( 1 a – d , 2 ) has been synthesised and spectroscopically investigated. All the dyes, except pH‐responsive 1 d in polar solvents, display intense emission between 550–700 nm. Compounds 1 a and 1 b with a hydrogen atom and a methyl group in the meso position of the BODIPY core show spectroscopic properties that are similar to those of rhodamine 101, thus rendering them potent alternatives to the positively charged rhodamine dyes as stains and labels for less polar environments or for the dyeing of latex beads. Compound 1 d , which carries an electron‐donating 4‐(dimethylamino)phenyl group in the meso position, shows dual fluorescence in solvents more polar than dibutyl ether and can act as a pH‐responsive “light‐up” probe for acidic pH. Correlation of the pKa data of 1 d and several other meso‐(4‐dimethylanilino)‐substituted BODIPY derivatives allowed us to draw conclusions on the influence of steric crowding at the meso position on the acidity of the aniline nitrogen atom. Preparation and investigation of 2 , which carries a nitrogen instead of a carbon as the meso‐bridgehead atom, suggests that the rules of colour tuning of BODIPYs as established so far have to be reassessed; for all the reported couples of meso‐C‐ and meso‐N‐substituted BODIPYs, the exchange leads to pronounced redshifts of the spectra and reduced fluorescence quantum yields. For 2 , when compared with 1 a , the opposite is found: negligible spectral shifts and enhanced fluorescence. Additional X‐ray crystallographic analysis of 1 a and quantum chemical modelling of the title and related compounds employing density functional theory granted further insight into the features of such sterically crowded chromophores. 相似文献
10.
Beatrice Karg Andrea Funke Anna Ficht Adrian Sievers‐Engler Prof. Dr. Michael Lämmerhofer Prof. Dr. Klaus Weisz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13802-13811
The interactions of a dicarbocyanine dye 3,3′‐diethylthiadicarbocyanine, DiSC2(5) , with DNA G‐quadruplexes were studied by means of a combination of various spectroscopic techniques. Aggregation of excess dye as a result of its positive charge is promoted by the presence of the polyanionic quadruplex structure. Specific high‐affinity binding to the parallel quadruplex of the MYC promoter sequence involves stacking of DiSC2(5) on the external G‐tetrads; the 5′‐terminal tetrad is the favored binding site. Significant energy transfer between DNA and the dye in the UV spectral region is observed upon DiSC2(5) binding. The transfer efficiency strongly depends on the DNA secondary structure as well as on the G‐quadruplex topology. These photophysical features enable the selective detection of DNA quadruplexes through sensitized DiSC2(5) fluorescence in the visible region. 相似文献
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Dr. Mariusz Tasior Vincent Hugues Dr. Mireille Blanchard‐Desce Prof. Daniel T. Gryko 《化学:亚洲杂志》2012,7(11):2656-2661
New, strongly fluorescent benzo[1,2‐d:4,5‐d′]bisimidazoles have been prepared by the reaction of Bandrowski′s base with various aldehydes. Their structures were carefully designed to achieve efficient excited‐state intramolecular proton transfer and good two‐photon‐absorption (2PA) cross‐sections. Functional dyes that possessed both high fluorescence quantum yields and large Stokes shifts were prepared. A π‐expanded D‐A‐D derivative that possessed Φfl=50 % and σ2=230 GM in the spectroscopic area of interest for biological imaging is an excellent candidate as a fluorescent probe. Thanks to the presence of two reactive amino groups, such compounds can be easily transformed into probes for bioconjugation. All of these benzo[1,2‐d:4,5‐d′]bisimidazoles were also strongly fluorescent in the solid state. 相似文献
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Thoresen LH Jiao GS Haaland WC Metzker ML Burgess K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(19):4603-4610
Syntheses of a unique set of energy transfer dye labeled nucleoside triphosphates, compounds 1-3, are described. Attempts to prepare these compounds were only successful if the triphosphorylation reaction was performed before coupling the dye to the nucleobase, and not the other way around. Compounds were prepared as both the 2'-deoxy (a) and 2',3'-dideoxy- (b) forms. They feature progressively longer rigid conjugated linkers connecting the nucleobase and the hydroxyxanthone moiety. UV spectra of the parent nucleosides 12-14 show that as the length of the linker increases so does the absorption of the donor in the 320-330 nm region, but with relatively little red-shift of the maxima. Fluorescence spectra of the same compounds show that radiation in the 320-330 nm region results in predominant emission from the fluorescein. When the linker is irradiated at 320 nm, the only significant emission observed corresponds to the hydroxyxanthone part of the molecules at 520 nm; this corresponds to an effective Stokes' shift of 200 nm. As the absorption at 320-330 nm by the linker increases with length, so does the intensity of the fluorescein emission. A gel assay was used to gauge relative incorporation efficiencies of compounds 1-3, dTTP, ddTTP, and 6-TAMRA-ddTTP. Throughout, the thermostable polymerase TaqFS was used, as it is the one most widely applied in high throughput DNA sequencing. This assay showed that only compounds 3 were incorporated efficiently; these have the longest linkers. Of these, the 2'-deoxy nucleoside 3 a was incorporated and did not prevent the polymerase from extending the chain further. The 2',3'-dideoxy nucleoside 3 b was incorporated only about 430 times less efficiently than ddTTP under the same conditions, and caused chain termination. The implications of these studies on modified sequencing protocols are discussed. 相似文献
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Ute Wild Dr. Christiane Neuhäuser Sven Wiesner Dr. Elisabeth Kaifer Prof. Dr. Hubert Wadepohl Prof. Dr. Hans‐Jörg Himmel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):5914-5925
Herein the synthesis, structures and properties of hydrogen‐bonded aggregates involving redox‐active guanidine superbases are reported. Reversible hydrogen bonding is switched on by oxidation of the hydrogen‐donor unit, and leads to formation of aggregates in which the hydrogen‐bond donor unit is sandwiched by two hydrogen‐bond acceptor units. Further oxidation (of the acceptor units) leads again to deaggregation. Aggregate formation is associated with a distinct color change, and the electronic situation could be described as a frozen stage on the way to hydrogen transfer. A further increase in the basicity of the hydrogen‐bond acceptor leads to deprotonation reactions. 相似文献
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Susith R. Galle Kankanamge Jianbo Ma Robert T. Mackin Fedra M. Leonik Carol M. Taylor Igor V. Rubtsov Daniel G. Kuroda 《Angewandte Chemie (International ed. in English)》2020,59(39):17012-17017
Hydrogen bonds (H bonds) play a major role in defining the structure and properties of many substances, as well as phenomena and processes. Traditional H bonds are ubiquitous in nature, yet the demonstration of weak H bonds that occur between a highly polarized C?H group and an electron‐rich oxygen atom, has proven elusive. Detailed here are linear and nonlinear IR spectroscopy experiments that reveal the presence of H bonds between the chloroform C?H group and an amide carbonyl oxygen atom in solution at room temperature. Evidence is provided for an amide solvation shell featuring two clearly distinguishable chloroform arrangements that undergo chemical exchange with a time scale of about 2 ps. Furthermore, the enthalpy of breaking the hydrogen bond is found to be 6–20 kJ mol?1. Ab‐initio computations support the findings of two distinct solvation shells formed by three chloroform molecules, where one thermally undergoes hydrogen‐bond making and breaking. 相似文献
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Won‐Sik Han Kyung‐Ryang Wee Hyun‐Young Kim Prof. Chyongjin Pac Yu Nabetani Daisuke Yamamoto Tetsuya Shimada Prof. Haruo Inoue Heesung Choi Prof. Kyeongjae Cho Prof. Sang Ook Kang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(48):15368-15381
Visible‐light‐driven H2 evolution based on Dye/TiO2/Pt hybrid photocatalysts was investigated for a series of (E)‐3‐(5′‐{4‐[bis(4‐R1‐phenyl)amino]phenyl}‐4,4′‐(R2)2‐2,2′‐bithiophen‐5‐yl)‐2‐cyanoacrylic acid dyes. Efficiencies of hydrogen evolution from aqueous suspensions in the presence of ethylenediaminetetraacetic acid as electron donor under illumination at λ>420 nm were found to considerably depend on the hydrophilic character of R1, varying in the order MOD (R1=CH3OCH2, R2=H)≈ MO4D (R1=R2=CH3OCH2)> HD (R1=R2=H)> PD (R1=C3H7, R2=H). In the case of MOD /TiO2/Pt, the apparent quantum yield for photocatalyzed H2 generation at 436 nm was 0.27±0.03. Transient absorption measurements for MOD ‐ or PD ‐grafted transparent films of TiO2 nanoparticles dipped into water at pH 3 commonly revealed ultrafast formation (<100 fs) of the dye radical cation (Dye.+) followed by multicomponent decays, which involve minor fast decays (<5 ps) almost independent of R1 and major slower decays with significant differences between the two samples: 1) the early decay of the major components for MOD is about 2.5 times slower than that for PD and 2) a redshift of the spectrum occurred for MOD with a time constant of 17 ps, but not for PD . The substituent effects on H2 generation as well as on transient behavior have been discussed in terms substituent‐dependent charge recombination (CR) of Dye.+ with electrons in bulk, inner‐trap, and/or interstitial‐trap states, arising from different solvent reorganization. 相似文献
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Holger Fricke Dr. Kristina Bartl Andreas Funk Andreas Gerlach Dr. Markus Gerhards Prof. Dr. 《Chemphyschem》2008,9(17):2592-2600
As a model system for intramolecular proton/hydrogen‐transfer coordinates, the structure of 2,5‐dihydroxybenzoic acid is investigated for the ground, first electronically excited and also the ionic state. Combined IR/UV spectroscopy in molecular‐beam experiments is applied and the experimental results are interpreted by the application of DFT and CASPT2 methods. No proton or hydrogen transfer is observed, but evidence is given for a hydrogen dislocation of the intramolecular hydrogen bond in the S1 state and to lesser extent in the D0 state. To obtain direct information on the proton/hydrogen‐transfer coordinate, IR spectra are recorded both in the region of the OH and especially the CO stretching vibrations by also applying two new variants of combined IR/UV spectroscopy for the S1 and D0 states. The CO groups are directly involved in the hydrogen bond and, in contrast to the hydrogen‐bonded OH groups, the CO stretching frequencies can be observed in all electronic states. 相似文献
19.
N−H‐Type Excited‐State Proton Transfer in Compounds Possessing a Seven‐Membered‐Ring Intramolecular Hydrogen Bond
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Yi‐An Chen Fan‐Yi Meng Yen‐Hao Hsu Cheng‐Hsien Hung Chi‐Lin Chen Kun‐You Chung Wei‐Feng Tang Prof. Dr. Wen‐Yi Hung Prof. Dr. Pi‐Tai Chou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14688-14695
A series of compounds containing 5‐(2‐aminobenzylidene)‐2,3‐dimethyl‐3,5‐dihydro‐4H‐imidazol‐4‐one ( o ‐ABDI ) as the core chromophore with a seven‐membered‐ring N?H‐type intramolecular hydrogen bond have been synthesized and characterized. The acidity of the N?H proton and thus the hydrogen‐bond strength can be fine‐tuned by replacing one of the amino hydrogen atoms by a substituent R, the acidity increasing with increasing electron‐withdrawing strength of R, that is, in the order H<COCH3<COPh<Tosyl<COCF3. The tosyl and trifluoroacetyl derivatives undergo ultrafast, irreversible excited‐state intramolecular proton transfer (ESIPT) that results in proton‐transfer emission solely in the red region. Reversible ESIPT, and hence dual emission, involving the normal and proton‐transfer tautomers was resolved for the acetyl‐ and benzyl‐substituted counterparts. For o ‐ABDI , which has the weakest acidity, ESIPT is prohibited due to its highly endergonic reaction. The results clearly demonstrate the harnessing of ESIPT by modifying the proton acidity and hydrogen‐bonding strength in a seven‐membered‐ring intramolecular hydrogen‐bonding system. For all the compounds studied, the emission quantum yields are weak (ca. 10?3) in dichloromethane, but strong in the solid form, ranging from 3.2 to 47.4 %. 相似文献
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Xunchen Liu Nicole Borho Dr. Yunjie Xu Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(1):270-277
Fluoroalcohols show competitive formation of intra‐ and intermolecular hydrogen bonds, a property that may be crucial for the protein‐altering process in a fluoroalcohol/water solution. In this study, we examine the intra‐ and intermolecular interactions of 2‐fluoroethanol (FE) in its dimeric conformers by using rotational spectroscopy and ab initio calculations. Three pairs of homo‐ and heterochiral dimeric FE conformers are predicted to be local minima at the MP2/6‐311++G(d,p) level of theory. They are solely made of the slightly distorted most stable G+g?/G?g+ FE monomer units. Jet‐cooled rotational spectra of four out of the six predicted dimeric conformers were observed and unambiguously assigned for the first time. All four observed dimeric conformers have compact geometries in which the fluoromethyl group of the acceptor tilts towards the donor and ensures a large contact area. Experimentally, the insertion of the O? H group of one FE subunit into the intramolecular O? H???F bond of the other was found to lead to a higher stabilisation than the pure association through an intermolecular O? H???O? H link. The hetero‐ and homochiral combinations were observed to be preferred in the inserted and the associated dimeric conformers, respectively. The experimental rotational constants and the stability ordering are compared with the ab initio calculations at the MP2 level with the 6‐311++G(d,p) and aug‐cc‐pVTZ basis sets. The effects of fluorination and the competing inter‐ and intramolecular hydrogen bonds on the stability of the dimeric FE conformers are discussed. 相似文献