共查询到20条相似文献,搜索用时 31 毫秒
1.
Nikolay Davydov Dr. Asiya Mustafina Dr. Vladimir Burilov Dr. Elena Zvereva Prof. Sergey Katsyuba Dr. Liliya Vagapova Prof. Alexander Konovalov Dr. Igor Antipin 《Chemphyschem》2012,13(14):3357-3364
The complex formation of d‐metal ions at the interface of TbIII‐doped silica nanoparticles modified by amino groups is introduced as a route to sensing d‐metal ions and some organic molecules. Diverse modes of surface modification (covalent and noncovalent) are used to fix amino groups onto the silica surface. The interfacial binding of d‐metal ions and complexes is the reason for the TbIII‐centered luminescence quenching. The regularities and mechanisms of quenching are estimated for the series of d‐metal ions and their complexes with chelating ligands. The obtained results reveal the interfacial binding of CuII ions as the basis of their quantitative determination in the concentration range 0.1–2.5 μM by means of steady‐state and time‐resolved fluorescence measurements. The variation of chelating ligands results in a significant effect on the quenching regularities due to diverse binding modes (inner or outer sphere) between amino groups at the interface of nanoparticles and FeIII ions. The applicability of the steady‐state and time‐resolved fluorescence measurements to sense both FeIII ions and catechols in aqueous solution by means of TbIII‐doped silica nanoparticles is also introduced. 相似文献
2.
Mengyuan Li Congli Wang Zhenghan Di Hui Li Jingfang Zhang Wenting Xue Meiping Zhao Ke Zhang Yuliang Zhao Lele Li 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(5):1364-1368
Developing simple and general approaches for the synthesis of nanometer‐sized DNA materials with specific morphologies and functionalities is important for various applications. Herein, a novel approach for the synthesis of a new set of DNA‐based nanoarchitectures through coordination‐driven self‐assembly of FeII ions and DNA molecules is reported. By fine‐tuning the assembly, Fe–DNA nanospheres of precise sizes and controlled compositions can be produced. The hybrid nanoparticles can be tailored for delivery of functional DNA to cells in vitro and in vivo with enhanced biological function. This highlights the potential of metal ion coordination as a tool for directing the assembly of DNA architectures, which conceptualizes a new pathway to expand the repertoire of DNA‐based nanomaterials. This methodology will advance both the fields of DNA nanobiotechnology and metal–ligand coordination chemistry. 相似文献
3.
Iron(III)‐Quantity‐Dependent Aggregation–Dispersion Conversion of Functionalized Gold Nanoparticles 下载免费PDF全文
Linyi Bai Dr. Liangliang Zhu Chung Yen Ang Dr. Xin Li Shaojue Wu Dr. Yongfei Zeng Prof. Hans Ågren Prof. Yanli Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(14):4032-4037
Developing gold nanoparticles (AuNPs) with well‐designed functionality is highly desirable for boosting the performance and versatility of inorganic–organic hybrid materials. In an attempt to achieve ion recognition with specific signal expressions, we present here 4‐piperazinyl‐1,8‐naphthalimide‐functionalized AuNPs for the realization of quantitative recognition of FeIII ions with dual (colorimetric and fluorescent) output. The research takes advantage of 1) quantity‐controlled chelation‐mode transformation of the piperazinyl moiety on the AuNPs towards FeIII, thereby resulting in an aggregation–dispersion conversion of the AuNPs in solution, and 2) photoinduced electron transfer of a naphthaimide fluorophore on the AuNPs, thus leading to reversible absorption and emission changes. The functional AuNPs are also responsive to pH variations. This strategy for realizing the aggregation–dispersion conversion of AuNPs with returnable signal output might exhibit application potential for advanced nanoscale chemosensors. 相似文献
4.
Mussel‐Inspired Protein Nanoparticles Containing Iron(III)–DOPA Complexes for pH‐Responsive Drug Delivery 下载免费PDF全文
Dr. Bum Jin Kim Hogyun Cheong Dr. Byeong Hee Hwang Prof. Hyung Joon Cha 《Angewandte Chemie (International ed. in English)》2015,54(25):7318-7322
A novel bioinspired strategy for protein nanoparticle (NP) synthesis to achieve pH‐responsive drug release exploits the pH‐dependent changes in the coordination stoichiometry of iron(III)–3,4‐dihydroxyphenylalanine (DOPA) complexes, which play a major cross‐linking role in mussel byssal threads. Doxorubicin‐loaded polymeric NPs that are based on FeIII–DOPA complexation were thus synthesized with a DOPA‐modified recombinant mussel adhesive protein through a co‐electrospraying process. The release of doxorubicin was found to be predominantly governed by a change in the structure of the FeIII–DOPA complexes induced by an acidic pH value. It was also demonstrated that the fabricated NPs exhibited effective cytotoxicity towards cancer cells through efficient cellular uptake and cytosolic release. Therefore, it is anticipated that FeIII–DOPA complexation can be successfully utilized as a new design principle for pH‐responsive NPs for diverse controlled drug‐delivery applications. 相似文献
5.
Dr. Graham N. Newton Dr. Kiyotaka Mitsumoto Rong‐Jia Wei Fumichika Iijima Dr. Takuya Shiga Prof. Dr. Hiroyuki Nishikawa Prof. Dr. Hiroki Oshio 《Angewandte Chemie (International ed. in English)》2014,53(11):2941-2944
A bulky bidentate ligand was used to stabilize a macrocyclic [FeIII8CoII6] cluster. Tuning the basicity of the ligand by derivatization with one or two methoxy groups led to the isolation of a homologous [FeIII8CoII6] species and a [FeIII6FeII2CoIII2CoII2] complex, respectively. Lowering the reaction temperatures allowed isolation of [FeIII6FeII2CoIII2CoII2] clusters with all three ligands. Temperature‐dependent absorption data and corresponding experiments with iron/nickel systems indicated that the iron/cobalt self‐assembly process was directed by the occurrence of solution‐state electron‐transfer‐coupled spin transition (ETCST) and its influence on reaction intermediate lability. 相似文献
6.
Highly Luminescent and Stable Hydroxypyridinonate Complexes: A Step Towards New Curium Decontamination Strategies 下载免费PDF全文
Dr. Manuel Sturzbecher‐Hoehne Birgitta Kullgren Erin E. Jarvis Dahlia D. An Dr. Rebecca J. Abergel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9962-9968
The photophysical properties, solution thermodynamics, and in vivo complex stabilities of CmIII complexes formed with multidentate hydroxypyridinonate ligands, 3,4,3‐LI(1,2‐HOPO) and 5‐LIO(Me‐3,2‐HOPO), are reported. Both chelators were investigated for their ability to act as antenna chromophores for CmIII, leading to highly sensitized luminescence emission of the metal upon complexation, with long lifetimes (383 and 196 μs for 3,4,3‐LI(1,2‐HOPO) and 5‐LIO(Me‐3,2‐HOPO), respectively) and remarkable quantum yields (45 % and 16 %, respectively) in aqueous solution. The bright emission peaks were used to probe the electronic structure of the 5f complexes and gain insight into ligand field effects; they were also exploited to determine the high (and proton‐independent) stabilities of the corresponding CmIII complexes (log β110=21.8(4) for 3,4,3‐LI(1,2‐HOPO) and log β120=24.5(5) for 5‐LIO(Me‐3,2‐HOPO)). The in vivo complex stability for both ligands was assessed by using 248Cm as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results and demonstrated the great potential of 3,4,3‐LI(1,2‐HOPO) as a therapeutic CmIII decontamination agent. 相似文献
7.
8.
Xuezhao Li Jinguo Wu Lei Wang Cheng He Liyong Chen Yang Jiao Chunying Duan 《Angewandte Chemie (International ed. in English)》2020,59(16):6420-6427
The development of DNA‐targeted photodynamic therapy (PDT) agents for cancer treatment has drawn substantial attention. Herein, the design and synthesis of dinuclear IrIII‐containing luminescent metallohelices with tunable PDT efficacy that target mitochondrial DNA in cancer cells are reported. The metallohelices are fabricated using dynamic imine‐coupling chemistry between aldehyde end‐capped fac‐Ir(ppy)3 handles and linear alkanediamine spacers, followed by reduction of the imine linkages. The length and odd–even character of the diamine alkyl linker determined the stereochemistry (helicates vs. mesocates). Compared to the helicates, the mesocates exhibit improved apoptosis‐induction upon white‐light irradiation. Molecular docking studies indicate that the mesocate with a proper length of diamine spacers shows stronger affinity for the minor groove of DNA. This study highlights the potential of DNA‐targeting IrIII‐containing metallohelices as PDT agents. 相似文献
9.
Synthesis and characterization of 4‐AMTT‐Pd(II) complex over Fe3O4@SiO2 as supported nanocatalyst for Suzuki‐Miyaura and Mizoroki‐heck cross‐coupling reactions in water 下载免费PDF全文
Immobilization of Pd(II) nanoparticles on silica‐coated modified magnetite particles has been readily achieved via a surface modification of Fe3O4 particles with 4‐amino‐5‐methyl‐4‐H‐1,2,4‐triazole‐3‐thiol (4‐AMTT) as a ligand. This magnetite nanocatalyst was characterized by various analyses such as FT‐IR, SEM/EDX, ICP‐AES, VSM, TEM, XRD, XPS and TGA. This nanocatalyst showed admirable catalytic activity for Suzuki‐Miyaura and Mizoroki‐Heck cross‐coupling reactions under mild conditions in water, and could be simply separated by an outer magnet and reused for several times. 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2018,130(39):12862-12866
Three‐component mixtures (diblock copolymer/metal ion/oligoligand) can assemble into micellar particles owing to a combination of supramolecular polymerization and electrostatic complex formation. Such particles cover a large range of compositions, but the electrostatic forces keeping them together make them rather susceptible to disintegration by added salt. Now it is shown how the salt stability can be tuned continuously by employing both a bis‐ligand and a tris‐ligand, and varying the ratio of these in the mixture. For magnetic ions such as MnII and FeIII, the choice of the multiligand also affects the ion/water interaction and, hence, the magnetic relaxivity. As an example, MnII‐based nanoparticles with a very high longitudinal relaxivity (10.8 mm −1 s−1) were investigated that are not only biocompatible but also feature strong contrast enhancement in target organs (liver, kidney), as shown by T1‐weighted in vivo magnetic resonance imaging (MRI). 相似文献
11.
Redox‐Assisted Self‐Assembly of a Water‐Soluble Cyanido‐Bridged Mixed Valence {CoIII/FeII}2 Square 下载免费PDF全文
Laura Alcázar Dr. Gabriel Aullón Dr. Montserrat Ferrer Prof. Manuel Martínez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(43):15227-15230
The facile redox‐assisted assembly of a water‐soluble, extremely robust, cyanide‐bridged mixed‐valence [{CoIII{(Me)2(μ‐ET)cyclen}}2{(μ‐NC)2FeII(CN)4}2]2? square is reported. The preparation process involved the use of the enhanced lability of inert CoIII synthons triggered by outer‐sphere redox processes. Characterization of the final compounds has been carried out by NMR, UV/Vis, electrochemistry, and ICP analyses. DFT calculations have been conducted to optimize a structure that has the same hydrodynamic radius as that obtained from DOSY experiments. The new compound is extremely robust, surviving in aqueous solution within the 0–12 pH range for months. The species shows a high affinity for both protons and hydroxo ions in aqueous medium. 相似文献
12.
Juan Chen Stepan Stepanovic Dr. Apparao Draksharapu Prof. Dr. Maja Gruden Prof. Dr. Wesley R. Browne 《Angewandte Chemie (International ed. in English)》2018,57(12):3207-3211
Non‐heme (L)FeIII and (L)FeIII‐O‐FeIII(L) complexes (L=1,1‐di(pyridin‐2‐yl)‐N,N‐bis(pyridin‐2‐ylmethyl)ethan‐1‐amine) underwent reduction under irradiation to the FeII state with concomitant oxidation of methanol to methanal, without the need for a secondary photosensitizer. Spectroscopic and DFT studies support a mechanism in which irradiation results in charge‐transfer excitation of a FeIII?μ‐O?FeIII complex to generate [(L)FeIV=O]2+ (observed transiently during irradiation in acetonitrile), and an equivalent of (L)FeII. Under aerobic conditions, irradiation accelerates reoxidation from the FeII to the FeIII state with O2, thus closing the cycle of methanol oxidation to methanal. 相似文献
13.
Direct Observation of Ordered High‐Spin–Low‐Spin Intermediate States of an Iron(III) Three‐Step Spin‐Crossover Complex 下载免费PDF全文
Dr. Zhao‐Yang Li Dr. Hiroyoshi Ohtsu Dr. Tatsuhiro Kojima Dr. Jing‐Wei Dai Takefumi Yoshida Dr. Brian K. Breedlove Dr. Wei‐Xiong Zhang Dr. Hiroaki Iguchi Prof. Osamu Sato Prof. Masaki Kawano Prof. Masahiro Yamashita 《Angewandte Chemie (International ed. in English)》2016,55(17):5184-5189
A neutral mononuclear FeIII complex [FeIII(H‐5‐Br‐thsa‐Me)(5‐Br‐thsa‐Me)]?H2O ( 1 ; H2‐5‐Br‐thsa‐Me=5‐bromosalicylaldehyde methylthiosemicarbazone) was prepared that exhibited a three‐step spin‐crossover (SCO) with symmetry breaking and a 14 K hysteresis loop owing to strong cooperativity. Two ordered intermediate states of 1 were observed, 4HS–2LS and 2HS–4LS, which exhibited reentrant phase‐transition behavior. This study provides a new platform for examining multistability in SCO complexes. 相似文献
14.
Wen Wen Yin‐Shan Meng Cheng‐Qi Jiao Qiang Liu Hai‐Lang Zhu Ya‐Ming Li Hiroki Oshio Tao Liu 《Angewandte Chemie (International ed. in English)》2020,59(38):16393-16397
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a FeII‐triazole moiety and generates a mixed‐valence complex {[(Tp4‐Me)FeIII(CN)3]9[FeII4(trz‐ph)6]}?[Ph3PMe]2?[(Tp4‐Me)FeIII(CN)3] ( 1 ; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between FeIII and one of the FeII sites after heat treatment, resulting in the generation of a new phase, {[(Tp4‐Me)FeII(CN)3][(Tp4‐Me)FeIII(CN)3]8 [FeIIIFeII3(trz‐ph)6]}? [Ph3PMe]2?[(Tp4‐Me)FeIII(CN)3] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states. 相似文献
15.
Tuning the Cellular Uptake Properties of Luminescent Heterobimetallic Iridium(III)–Ruthenium(II) DNA Imaging Probes 下载免费PDF全文
Dr. Ashley Wragg Dr. Martin R. Gill Dr. David Turton Harry Adams Thomas M. Roseveare Prof. Carl Smythe Dr. Xiaodi Su Dr. Jim A. Thomas 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(43):14004-14011
The synthesis of two new luminescent dinuclear IrIII–RuII complexes containing tetrapyrido[3,2‐a:2′,3′‐c:3′′,2′′‐h:2′′′,3′′′‐j]phenazine (tpphz) as the bridging ligand is reported. Unlike many other complexes incorporating cyclometalated IrIII moieties, these complexes display good water solubility, allowing the first cell‐based study on IrIII–RuII bioprobes to be carried out. Photophysical studies indicate that emission from each complex is from a RuII excited state and both complexes display significant in vitro DNA‐binding affinities. Cellular studies show that each complex is rapidly internalised by HeLa cells, in which they function as luminescent nuclear DNA‐imaging agents for confocal microscopy. Furthermore, the uptake and nuclear targeting properties of the complex incorporating cyclometalating 2‐(4‐fluorophenyl)pyridine ligands around its IrIII centre is enhanced in comparison to the non‐fluorinated analogue, indicating that fluorination may provide a route to promote cell uptake of transition‐metal bioprobes. 相似文献
16.
Zhicheng Zhang Yifeng Chen Xiaobin Xu Jingchao Zhang Guolei Xiang Wei He Prof. Xun Wang 《Angewandte Chemie (International ed. in English)》2014,53(2):429-433
Metal–organic frameworks (MOFs) have demonstrated great potentials in a variety of important applications. To enhance the inherent properties and endow materials with multifunctionality, the rational design and synthesis of MOFs with nanoscale porosity and hollow feature is highly desired and remains a great challenge. In this work, the formation of a series of well‐defined MOF (MOF‐5, FeII‐MOF‐5, FeIII‐MOF‐5) hollow nanocages by a facile solvothermal method, without any additional supporting template is reported. A surface‐energy‐driven mechanism may be responsible for the formation of hollow nanocages. The addition of pre‐synthesized poly(vinylpyrrolidone)‐ (PVP) capped noble‐metal nanoparticles into the synthetic system of MOF hollow nanocages yields the yolk–shell noble metal@MOF nanostructures. The present strategy to fabricate hollow and yolk–shell nanostructures is expected to open up exciting opportunities for developing a novel class of inorganic–organic hybrid functional nanomaterials. 相似文献
17.
Shi Kuang Xinxing Liao Xianrui Zhang Thomas W. Rees Ruilin Guan Kai Xiong Yu Chen Liangnian Ji Hui Chao 《Angewandte Chemie (International ed. in English)》2020,59(8):3315-3321
Reported is the FeIII‐activated lysosome‐targeting prodrug FerriIridium for gastric cancer theranostics. It contains a meta‐imino catechol group that can selectively bond to, and be oxidized by, free FeIII inside the cell. Subsequent oxidative rearrangement releases FeII and hydrolyses the amine bond under acidic conditions, forming an aminobipyridyl Ir complex and 2‐hydroxybenzoquinone. Thus, FeII catalyzes the Fenton reaction, transforming hydrogen peroxide into hydroxyl radicals, the benzoquinone compounds interfere with the respiratory chain, and conversion of the prodrug into the Ir complex leads to an increase in phosphorescence and toxicity. These properties, combined with the high FeIII content and acidity of cancer cells, make FerriIridium a selective and efficient theranostic agent (IC50=9.22 μm for AGS cells vs. >200 μm for LO2 cells). FerriIridium is the first metal‐based compound that has been developed for chemotherapy using FeIII to enhance both selectivity and potency. 相似文献
18.
We have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral FeII and BiIII complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (?78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water‐compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1 , which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a FeII or BiIII metal salt, a chiral ligand ( L1 ), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo‐ and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the FeII and BiIII centers and the effect of additives on the chiral catalysis. Notably, both Brønsted acids and bases worked as efficient additives in the FeII‐catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems. 相似文献
19.
Dr. Yoann Prado Dr. Marie‐Anne Arrio Dr. Florence Volatron Dr. Edwige Otero Dr. Christophe Cartier dit Moulin Dr. Philippe Sainctavit Dr. Laure Catala Prof. Dr. Talal Mallah 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(21):6685-6694
The local symmetry and local magnetic properties of 6 nm‐sized, bimetallic, cyanide‐bridged CsNiCr(CN)6 coordination nanoparticles 1 and 8 nm‐sized, trimetallic, CsNiCr(CN)6@CsCoCr(CN)6 core–shell nanoparticles 2 were studied by X‐ray absorption spectroscopy (XAS) and X‐ray magnetic circular dichroism (XMCD). The measurements were performed at the NiII, CoII, and CrIII L2,3 edges. This study revealed the presence of distorted NiII sites located on the particle surface of 1 that account for the uniaxial magnetic anisotropy observed by SQUID measurements. For the core–shell particles, a combination of the exchange anisotropy between the core and the shell and the pronounced anisotropy of the CoII ions is the origin of the large increase in coercive field from 120 to 890 Oe on going from 1 to 2 . In addition, XMCD allows the relative orientation of the magnetic moments throughout the core–shell particles to be determined. While for the bimetallic particles of 1 , alignment of the magnetic moments of CrIII ions with those of NiII ions leads to uniform magnetization, in the core–shell particles 2 the magnetic moments of the isotropic CrIII follow those of CoII ions in the shell and those of NiII ions in the core, and this leads to nonuniform magnetization in the whole nanoobject, mainly due to the large difference in local anisotropy between the CoII ions belonging to the surface and the NiII ions in the core. 相似文献
20.
Peng Zhou Wei Ren Gang Nie Xiaojie Li Xiaoguang Duan Yongli Zhang Shaobin Wang 《Angewandte Chemie (International ed. in English)》2020,59(38):16517-16526
Generation of hydroxyl radicals in the Fenton system (FeII/H2O2) is seriously limited by the sluggish kinetics of FeIII reduction and fast FeIII precipitation. Here, boron crystals (C‐Boron) remarkably accelerate the FeIII/FeII circulation in Fenton‐like systems (C‐Boron/FeIII/H2O2) to produce a myriad of hydroxyl radicals with excellent efficiencies in oxidative degradation of various pollutants. The surface B?B bonds and interfacial suboxide boron in the surface B12 icosahedra are the active sites to donate electrons to promote fast FeIII reduction to FeII and further enhance hydroxyl radical production via Fenton chemistry. The C‐Boron/FeIII/H2O2 system outperforms the benchmark Fenton (FeII/H2O2) and FeIII‐based sulfate radical systems. The reactivity and stability of crystalline boron is much higher than the popular molecular reducing agents, nanocarbons, and other metal/metal‐free nanomaterials. 相似文献