共查询到20条相似文献,搜索用时 0 毫秒
1.
Dr. Agnese Marcelli Dr. Barbara Patrizi Prof. Alessandra Bonamore Prof. Alberto Boffi Prof. Maurizio Becucci Prof. Paolo Foggi 《Chemphyschem》2021,22(11):1134-1140
Flavohemoglobins have the particular capability of binding unsaturated and cyclopropanated fatty acids as free acids or phospholipids. Fatty acid binding to the ferric heme results in a weak but direct bonding interaction. Ferrous and ferric protein, in presence or absence of a bound lipid molecule, have been characterized by transient absorption spectroscopy. Measurements have been also carried out both on the ferrous deoxygenated and on the CO bound protein to investigate possible long-range interaction between the lipid acyl chain moiety and the ferrous heme. After excitation of the deoxygenated derivatives the relaxation process reveals a slow dynamics (350 ps) in lipid-bound protein but is not observed in the lipid-free protein. The latter feature and the presence of an extra contribution in the absorption spectrum, indicates that the interaction of iron heme with the acyl chain moiety occurs only in the excited electronic state and not in the ground electronic state. Data analysis highlights the formation of a charge-transfer complex in which the iron ion of the lipid-bound protein in the expanded electronic excited state, possibly represented by a high spin Fe III intermediate, is able to bind to the sixth coordination ligand placed at a distance of at 3.5 Å from the iron. A very small nanosecond geminate rebinding is observed for CO adduct in lipid-free but not in the lipid-bound protein. The presence of the lipid thus appears to inhibit the mobility of CO in the heme pocket. 相似文献
2.
De-Hai Liu Kyogo Nagashima Hui Liang Xue-Lin Yue Yun-Peng Chu Shuming Chen Jiajia Ma 《Angewandte Chemie (International ed. in English)》2023,62(48):e202312203
(Hetero)arene reduction is one of the key avenues for synthesizing related cyclic alkenes and alkanes. While catalytic hydrogenation and Birch reduction are the two broadly utilized approaches for (hetero)arene reduction across academia and industry over the last century, both methods have encountered significant chemoselectivity challenges. We hereby introduce a highly chemoselective quinoline and isoquinoline reduction protocol operating through selective energy transfer (EnT) catalysis, which enables subsequent hydrogen atom transfer (HAT). The design of this protocol bypasses the conventional metric of reduction reaction, that is, the reductive potential, and instead relies on the triplet energies of the chemical moieties and the kinetic barriers of energy and hydrogen atom transfer events. Many reducing labile functional groups, which were incompatible with previous (hetero)arene reduction reactions, are retained in this reaction. We anticipate that this protocol will trigger the further advancement of chemoselective arene reduction and enable the current arene-rich drug space to escape from flatland. 相似文献
3.
Yu-Che Chang Christophe Salome Thomas Fessard Prof. M. Kevin Brown 《Angewandte Chemie (International ed. in English)》2023,62(51):e202314700
Rigid bicycles are becoming more popular in the pharmaceutical industry because they allow for expansion to new and unique chemical spaces. This work describes a new strategy to construct 2-azanorbornanes, which can act as rigid piperidine/pyrrolidine scaffolds with well-defined exit vectors. To achieve the synthesis of 2-azanorbornanes, new strain-release reagent, azahousane, is introduced along with its photosensitized strain-release formal cycloaddition with alkenes. Furthermore, new reactivity between a housane and an imine is disclosed. Both strategies lead to various substituted 2-azanorbornanes with good selectivities. 相似文献
4.
Huan Zong Xinxin Wang Xijiao Mu Jingang Wang Mengtao Sun 《Chemical record (New York, N.Y.)》2019,19(5):818-842
In this review, we firstly introduce physical mechanism of fluorescence resonance energy transfer (FRET), the methods to measure FRET efficiency, and the applications of FRET. Secondly, we introduce the principle and applications of plasmon‐enhanced fluorescence (PEF). Thirdly, we focused on the principle and applications of plasmon‐enhanced FRET. This review can promote further understanding of FRET and PE‐FRET. 相似文献
5.
Bernard Juskowiak Elzbieta Galezowska Teruhisa Ichihara Shigeori Takenaka Makoto Takagi Kenichi Yoshikawa 《Supramolecular chemistry》2013,25(6):477-485
The intermolecular cross-linking of DNA with a rigid bisintercalator, 1,4-bis(( N -methylquinolinium-4-yl)vinyl)benzene (pMQVB) has been studied using fluorescence resonance energy transfer (FRET), fluorescence anisotropy measurements, and dynamic fluorescence microscopy. Short DNA duplexes, single-labeled with fluorescein (donor) and x-rhodamine (acceptor), were used as energy transfer partners. Due to the quenching effect of pMQVB on the emission of both fluorescein and x-rhodamine, the energy transfer was monitored using the corrected Stern-Volmer plots. The cross-linking ability of pMQVB depended on the ligand structure; the planar E , E isomer cross-linked DNA contrary to the non-planar E , Z isomer. Dynamic fluorescence microscopy observation also demonstrated the ability of pMQVB to cross-link large T4 DNA molecules. 相似文献
6.
Dr. Ting He Prof. Yanli Zhao 《Angewandte Chemie (International ed. in English)》2023,62(34):e202303086
Intensifying energy crises and severe environmental issues have led to the discovery of renewable energy sources, sustainable energy conversion, and storage technologies. Photocatalysis is a green technology that converts eco-friendly solar energy into high-energy chemicals. Covalent organic frameworks (COFs) are porous materials constructed by covalent bonds that show promising potential for converting solar energy into chemicals owing to their pre-designable structures, high crystallinity, and porosity. Herein, we highlight recent progress in the synthesis of COF-based photocatalysts and their applications in water splitting, CO2 reduction, and H2O2 production. The challenges and future opportunities for the rational design of COFs for advanced photocatalysts are discussed. This Review is expected to promote further development of COFs toward photocatalysis. 相似文献
7.
Shuo Li Yunxia Liu Kun Feng Chengyu Li Jiabin Xu Cheng Lu Prof. Haiping Lin Yong Feng Prof. Ding Ma Prof. Jun Zhong 《Angewandte Chemie (International ed. in English)》2023,62(39):e202308670
Electrochemical water splitting is a promising approach for producing sustainable and clean hydrogen. Typically, high valence state sites are favorable for oxidation evolution reaction (OER), while low valence states can facilitate hydrogen evolution reaction (HER). However, here we proposed a high valence state of Co3+ in Ni9.5Co0.5−S−FeOx hybrid as the favorable center for efficient and stable HER, while structural analogues with low chemical states showed much worse performance. As a result, the Ni9.5Co0.5−S−FeOx catalyst could drive alkaline HER with an ultra-low overpotential of 22 mV for 10 mA cm−2, and 175 mV for 1000 mA cm−2 at the industrial temperature of 60 °C, with an excellent stability over 300 h. Moreover, this material could work for both OER and HER, with a low cell voltage being 1.730 V to achieve 1000 mA cm−2 for overall water splitting at 60 °C. X-ray absorption spectroscopy (XAS) clearly identified the high valence Co3+ sites, while in situ XAS during HER and theoretical calculations revealed the favorable electron capture at Co3+ and suitable H adsorption/desorption energy around Co3+, which could accelerate the HER. The understanding of high valence states to drive reductive reactions may pave the way for the rational design of energy-related catalysts. 相似文献
8.
Yi-Hsuan Wu Harshit Mehta Dr. Elena Willinger Dr. Jodie A. Yuwono Dr. Priyank V. Kumar Dr. Paula M. Abdala Dr. Anna Wach Dr. Agnieszka Kierzkowska Dr. Felix Donat Dr. Denis A. Kuznetsov Prof. Dr. Christoph R. Müller 《Angewandte Chemie (International ed. in English)》2023,62(8):e202217186
Establishing generic catalyst design principles by identifying structural features of materials that influence their performance will advance the rational engineering of new catalytic materials. In this study, by investigating metal-substituted manganese oxide (spinel) nanoparticles, Mn3O4:M (M=Sr, Ca, Mg, Zn, Cu), we rationalize the dependence of the activity of Mn3O4:M for the electrocatalytic oxygen reduction reaction (ORR) on the enthalpy of formation of the binary MO oxide, ΔfH°(MO), and the Lewis acidity of the M2+ substituent. Incorporation of elements M with low ΔfH°(MO) enhances the oxygen binding strength in Mn3O4:M, which affects its activity in ORR due to the established correlation between ORR activity and the binding energy of *O/*OH/*OOH species. Our work provides a perspective on the design of new compositions for oxygen electrocatalysis relying on the rational substitution/doping by redox-inactive elements. 相似文献
9.
Youxin Fu Dr. Georgios Alachouzos Jun.-Prof. Dr. Nadja A. Simeth Mariangela Di Donato Michiel F. Hilbers Wybren Jan Buma Prof. Dr. Wiktor Szymanski Prof. Dr. Ben L. Feringa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(21):e202319321
Photoclick reactions combine the advantages offered by light-driven processes and classical click chemistry and have found applications ranging from surface functionalization, polymer conjugation, photo-crosslinking, and protein labeling. Despite these advances, the dependency of most of the photoclick reactions on UV light poses a severe obstacle for their general implementation, as this light can be absorbed by other molecules in the system resulting in their degradation or unwanted reactivity. However, the development of a simple and efficient system to achieve bathochromically shifted photoclick transformations remains challenging. Here, we introduce triplet-triplet energy transfer as a fast and selective way to enable visible light-induced photoclick reactions. Specifically, we show that 9,10-phenanthrenequinones ( PQ s) can efficiently react with electron-rich alkenes ( ERA s) in the presence of a catalytic amount (as little as 5 mol %) of photosensitizers. The photocycloaddition reaction can be achieved under green (530 nm) or orange (590 nm) light irradiation, representing a bathochromic shift of over 100 nm as compared to the classical PQ-ERA s system. Furthermore, by combining appropriate reactants, we establish an orthogonal, blue and green light-induced photoclick reaction system in which the product distribution can be precisely controlled by the choice of the color of light. 相似文献
10.
Dr. Alberto Concellón Prof. Dr. Timothy M. Swager 《Angewandte Chemie (International ed. in English)》2023,62(47):e202309928
The ubiquitous presence of per- and polyfluoroalkyl substances (PFAS) in aqueous environments has aroused societal concern. Nonetheless, effective sensing technologies for continuous monitoring of PFAS within water distribution infrastructures currently do not exist. Herein, we describe a ratiometric sensing approach to selectively detect aqueous perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at concentrations of μg ⋅ L−1. Our method relies on the excitonic transport in a highly fluorinated poly(p-phenylene ethynylene) to amplify a ratiometric emission signal modulated by an embedded fluorinated squaraine dye. The electronic coupling between the polymer and dye occurs through overlap of π-orbitals and is designed such that energy transfer is dominated by an electron-exchange (Dexter) mechanism. Exposure to aqueous solutions of PFAS perturbs the orbital interactions between the squaraine dye and the polymer backbone, thereby diminishing the efficiency of the energy transfer and producing a “polymer-ON/dye-OFF” response. These polymer/dye combinations were evaluated in spin-coated films and polymer nanoparticles and were able to selectively detect PFAS at concentrations of ca. 150 ppb and ca. 50 ppb, respectively. Both polymer films and nanoparticles are not affected by the type of water, and similar responses to PFAS were found in milliQ and well water. 相似文献
11.
Ultrafast Energy Transfer in Artificial Antenna Molecule Measured by Transient Fluorescence Spectroscopy
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We have reported previously the ultrafast energy transfer process with a time constant of 0.8 ps from a monomeric to a dimeric subunit within a perylenetetracarboxylic diimide trimer, which was derived indirectly from a model fitting into the transient absorption ex-perimental data. Here we present a direct ultrafast fluorescence quenching measurement by employing fs time-resolved transient fluorescence spectroscopy based on noncollinear optical parametric amplification technique. The rapid decay of the monomer's emission due to en-ergy transfer was observed directly with a time constant of about 0.82 ps, in good agreement with the previous result. 相似文献
12.
Dr. Baobing Fan Dr. Wei Gao Dr. Rui Zhang Dr. Werner Kaminsky Lingxiao Tang Dr. Francis R. Lin Dr. Yiwen Wang Prof. Qunping Fan Prof. Wei Ma Prof. Feng Gao Prof. Alex K.-Y. Jen 《Angewandte Chemie (International ed. in English)》2023,62(46):e202311559
Organic photovoltaics (OPV) are one of the most effective ways to harvest renewable solar energy, with the power conversion efficiency (PCE) of the devices soaring above 19 % when processed with halogenated solvents. The superior photocurrent of OPV over other emerging photovoltaics offers more opportunities to further improve the efficiency. Tailoring the absorption band of photoactive materials is an effective way to further enhance OPV photocurrent. However, the field has mostly been focusing on improving the near-infrared region photo-response, with the absorption shoulders in short-wavelength region (SWR) usually being neglected. Herein, by developing a series of non-fullerene acceptors (NFAs) with varied side-group conjugations, we observe an enhanced SWR absorption band with increased side-group conjugation length. The underpinning factors of how molecular structures and geometries improve SWR absorption are clearly elucidated through theoretical modelling and crystallography. Moreover, a clear relationship between the enhanced SWR absorption and reduced singlet-triplet energy gap is established, both of which are favorable for the OPV performance and can be tailored by rational structure design of NFAs. Finally, the rationally designed NFA, BO-TTBr, affords a decent PCE of 18.5 % when processed with a non-halogenated green solvent. 相似文献
13.
microRNAs(miRNAs)的灵敏检测对临床诊断具有十分重要的意义.本研究采用偶联DNA聚合酶和核酸内切酶介导的恒温扩增反应实现靶标循环再生的策略,利用纳米金(AuNPs)与纳米银簇(AgNCs)间表面等离子增强能量转移效应,开发了一种miRNA定量检测方法.在AuNPs表面组装两种探针(Probe a和Probe b)制备响应元件Probe b-Probe a-AuNP,其中Probe a通过3′端巯基共价偶联到AuNPs表面,此外具有靶标miRNA互补序列、核酸内切酶酶切序列和Probe b互补序列,Probe b为荧光AgNCs合成模板.靶标miRNA存在时,启动酶级联恒温扩增反应,导致Probe b脱离AuNPs表面,抑制了Probe b为模板合成的AgNCs与AuNPs间表面等离子增强能量转移效应,使得反应体系荧光信号增强.本方法的检出限为2.5×10-11 mol/L,与miRNAs商业化检测试剂盒相比,避免了逆转录反应,而且操作简单,检测成本低,可应用于生物样本中miRNAs分析. 相似文献
14.
Intra-molecular Electronic Energy Transfer in Mono- and Di-nuclear Zinc(II) Supramolecular Complexes
Luigi Fabbrizzi Maurizio Licchelli Nathalie Marcotte Floriana Stomeo Angelo Taglietti 《Supramolecular chemistry》2013,25(2-3):127-132
Intra-molecular electronic energy transfer processes have been investigated in systems containing two distinct fluorophores Fl 1 (absorbing photonic energy) and Fl 2 (coumarin 343, brought at a close distance through coordinative interactions, emitting). Fl 1 is covalently linked or incorporated in a polyamine platform containing one or two Zn II ions, while Fl 2 coordinates the Zn II centre(s) through a carboxylate group. Zn II has been chosen for its photophysical inactivity and quick reversibility of the interaction with Fl 2 . 相似文献
15.
Sebastian V. Kruppa Cedric Groß Xin Gui Florian Bäppler Björn Kwasigroch Dr. Yu Sun Prof. Dr. Rolf Diller Prof. Dr. Wim Klopper Prof. Dr. Gereon Niedner-Schatteburg Dr. Christoph Riehn Prof. Dr. Werner R. Thiel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(48):11269-11284
The photoexcitation of a triangular silver(I) hydride complex, [Ag3(μ3-H)(μ2-dcpm)3](PF6)2 ([ P ](PF6)2, dcpm=bis(dicyclohexylphosphino)methane), designed with “UV-silent” bis-phosphine ligands, provokes hydride-to-Ag3 single and double electron transfer. The nature of the electronic transitions has been authenticated by absorption and photodissociation spectroscopy in parallel with high-level quantum-chemical computations utilizing the GW method and Bethe–Salpeter equation (GW-BSE). Specific photofragments of mass-selected [ P ]2+ ions testify to charge transfer and competing pathways resulting from the unique [Ag3(μ3-H)]2+ scaffold. This structural motif of [ P ](PF6)2 has been unequivocally verified by 1H NMR spectroscopy in concert with DFT and X-ray diffraction structural analysis, which revealed short equilateral Ag–Ag distances (dAgAg=3.08 Å) within the range of argentophilic interactions. The reduced radical cation [ P ] . + exhibits strong oxophilicity, forming [ P +O2] .+ ,which is a model intermediate for silver oxidation catalysis. 相似文献
16.
Dr. Dawid Pakulski Dr. Adam Gorczyński Daria Brykczyńska Dr. Verónica Montes-García Włodzimierz Czepa Dr. Iwona Janica Dr. Michał Bielejewski Prof. Maciej Kubicki Prof. Violetta Patroniak Prof. Paolo Samorì Dr. Artur Ciesielski 《Angewandte Chemie (International ed. in English)》2023,62(32):e202305239
The unique electrochemical properties of polyoxometalates (POMs) render them ideal components for the fabrication of next-generation high-performance energy storage systems. However, their practical applications have been hindered by their high solubility in common electrolytes. This problem can be overcome by the effective hybridization of POMs with other materials. Here we present the design and synthesis of two novel polyoxometalate-covalent organic frameworks (POCOF) via one-pot solvothermal strategy between an amino-functionalized Anderson-type POM and a trialdehyde-based building unit. We show that structural and functional complexity can be enriched by adding hydroxyl groups in the 2,4,6 position to the benzene-1,3,5-tricarbaldehyde allowing to exploit for the first time in POCOFs the keto-enol tautomerization as additional feature to impart greater chemical stability to the COFs and enhanced properties leading to large specific surface area (347 m2/g) and superior electrochemical performance of the POCOF-1 electrodes, when compared with POCOF-2 electrodes that possess only imine-type linkage and with pristine POM electrodes. Specifically, POCOF-1 electrodes display remarkable specific, areal, and volumetric capacitance (125 F/g, 248 mF/cm2 and 41.9 mF/cm3, respectively) at a current density of 0.5 A/g, a maximum energy density (56.2 Wh/kg), a maximum power density (3.7 kW/kg) and an outstanding cyclability (90 % capacitance retention after 5000 cycles). 相似文献
17.
Somaiyeh Charoughchi Jiang Tian Liu Melissa Berteau-Rainville Hannes Hase Mohammad S. Askari Shubham Bhagat Pat Forgione Ingo Salzmann 《Angewandte Chemie (International ed. in English)》2023,62(31):e202304964
Molecular p-dopants designed to undergo electron transfer with organic semiconductors are typically planar molecules with high electron affinity. However, their planarity can promote the formation of ground-state charge transfer complexes with the semiconductor host and results in fractional instead of integer charge transfer, which is highly detrimental to doping efficiency. Here, we show this process can be readily overcome by targeted dopant design exploiting steric hindrance. To this end, we synthesize and characterize the remarkably stable p-dopant 2,2′,2′′-(cyclopropane-1,2,3-triylidene)tris(2-(perfluorophenyl)acetonitrile) comprising pendant functional groups that sterically shield its central core while retaining high electron affinity. Finally, we demonstrate it outperforms a planar dopant of identical electron affinity and increases the thin film conductivity by up to an order of magnitude. We believe exploiting steric hindrance represents a promising design strategy towards molecular dopants of enhanced doping efficiency. 相似文献
18.
19.
Sonja Kracht Dr. Matthias Messerer Dr. Matthieu Lang Dr. Sonja Eckhardt Dr. Miriam Lauz Prof. Bernard Grobéty Prof. Katharina M. Fromm Prof. Bernd Giese 《Angewandte Chemie (International ed. in English)》2015,54(10):2912-2916
Some microorganisms perform anaerobic mineral respiration by reducing metal ions to metal nanoparticles, using peptide aggregates as medium for electron transfer (ET). Such a reaction type is investigated here with model peptides and silver as the metal. Surprisingly, Ag+ ions bound by peptides with histidine as the Ag+‐binding amino acid and tyrosine as photoinducible electron donor cannot be reduced to Ag nanoparticles (AgNPs) under ET conditions because the peptide prevents the aggregation of Ag atoms to form AgNPs. Only in the presence of chloride ions, which generate AgCl microcrystals in the peptide matrix, does the synthesis of AgNPs occur. The reaction starts with the formation of 100 nm Ag@AgCl/peptide nanocomposites which are cleaved into 15 nm AgNPs. This defined transformation from large nanoparticles into small ones is in contrast to the usually observed Ostwald ripening processes and can be followed in detail by studying time‐resolved UV/Vis spectra which exhibit an isosbestic point. 相似文献
20.
Serhii I. Vasylevskyi Dr. Sonja Kracht Paula Corcosa Prof. Dr. Katharina M. Fromm Prof. Dr. Bernd Giese Michael Füeg 《Angewandte Chemie (International ed. in English)》2017,56(21):5926-5930
The reduction of Ag+ ions to Ag0 atoms is a highly endergonic reaction step, only the aggregation to Agn clusters leads to an exergonic process. These elementary chemical reactions play a decisive role if Ag nanoparticles (AgNPs) are generated by electron transfer (ET) reactions to Ag+ ions. We studied the formation of AgNPs in peptides by photoinduced ET, and in c-cytochromes by ET from their Fe2+/hemes. Our earlier photoinduced experiments in peptides had demonstrated that histidine prevents AgNP formation. We have now observed that AgNPs can be easily synthesized with less-efficient Ag+-binding amino acids, and the rate increases in the order lysine<asparagine<aspartate<serine. The ability of Fe2+/hemes of c-cytochromes to reduce Ag+ to AgNPs was studied in an enzymatic experiment and with living bacteria Geobacter sulfurreducens (Gs). 相似文献