68631-52-7Relevant academic research and scientific papers
A Convenient Access to a [2]Rotaxane Proton Shuttle by Using a Fluorous Ponytail
Beyer, Ole,Hesseler, Britta,Lüning, Ulrich
, p. 2485 - 2495 (2015)
The properties of rotaxanes and their constituents, ring and axle, sometimes do not differ much from one another resulting in tedious workup. In the case of a rotaxane designed to shuttle protons across a biological membrane (3-4 nm), molecular weight, shape, and functional groups of axle and rotaxane are similar. But when the macrocyclic ring of the rotaxane carries a fluorous residue, the fluorous effect distinguishes the rotaxane from the axle because the latter carries no fluorine atoms. This concept has been exploited to synthesize a [2]rotaxane in which the macrocyclic ring is protonable and the axle contains a permanent positive charge. Upon protonation/deprotonation of the macrocycle, a shuttling process is induced, which can lead to the transport of protons.
Integration of recognition elements with macromolecular scaffolds: Effects on polymer self-assembly in the solid state
Shenhar, Roy,Sanyal, Amitav,Uzun, Oktay,Nakade, Hiroshi,Rotello, Vincent M.
, p. 4931 - 4939 (2004)
Polystyrene scaffolds were grafted with model functionalities featuring strongly interacting hydrogen bonding and aromatic stacking elements. Both glass transition temperatures and degree of microphase separation in functionalized block copolymers depend
Designing Cr complexes for a neutral Fe-Cr redox flow battery
Chen, Qing,Jia, Guochen,Mao, Jiatao,Ruan, Wenqing,Shi, Chuan,Yang, Shida
, p. 3171 - 3174 (2020)
We lay out the design principles of Cr complexes to address issues of slow kinetics and parasitic reactions in the Fe-Cr redox flow battery (ICRFB). We identify theoretically and experimentally dipicolinic acid as a promising ligand, and synthesize its derivative to improve the solubility of the Cr complex to 0.7 M. We couple it with ferrocyanide for a neutral ICRFB delivering 120 stable cycles.
A Supramolecular Crosslinker To Give Salt-Resistant Polyion Complex Micelles and Improved MRI Contrast Agents
Wang, Jiahua,Wang, Junyou,Ding, Peng,Zhou, Wenjuan,Li, Yuehua,Drechsler, Markus,Guo, Xuhong,Cohen Stuart, Martien A.
, p. 12680 - 12684 (2018)
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).
Hydration-Facilitated Fine-Tuning of the AIE Amphiphile Color and Application as Erasable Materials with Hot/Cold Dual Writing Modes
Huang, Jianbin,Jin, Hongjun,Li, Hongpeng,Xiao, Yunlong,Yan, Yun,Zhu, Zhiyang
, p. 10081 - 10086 (2020)
Hydration water greatly impacts the color of inorganic crystals, but it is still unknown whether hydration water can be utilized to systematically manipulate the emission color of organic luminescent groups. Now, metal ions with different hydration abilit
Immobilization of a molecular catalyst on carbon nanotubes for highly efficient electro-catalytic water oxidation
Li, Fusheng,Li,Tong, Lianpeng,Daniel, Quentin,G?thelid, Mats,Sun, Licheng
, p. 13948 - 13951 (2014)
Electrochemically driven water oxidation has been performed using a molecular water oxidation catalyst immobilized on hybrid carbon nanotubes and nano-material electrodes. A high turnover frequency (TOF) of 7.6 s-1together with a high catalytic current density of 2.2 mA cm-2was successfully obtained at an overpotential of 480 mV after 1 h of bulk electrolysis.
Non-Covalent Assembly of a Photoswitchable Surface
Cooper, Christopher G. F.,MacDonald, John C.,Soto, Ernesto,McGimpsey, W. Grant
, p. 1032 - 1033 (2004)
A noncovalently bound multilayered thin film in which individual layers are linked by metal ligand interactions undergoes a photochemically initiated permanent change in surface wettability. The film consists of three separate layers: a SAM on gold of 4-[(10-mercaptodecyl)oxy]pyridine-2,6-dicarboxylic acid, a layer of Cu(II) ions that are deposited onto the SAM and bind symmetrically in the site provided by the two carboxylate groups and the pyridyl nitrogen atom, and a layer of cis-2,2′-dipyridylethylene, which caps the Cu(II) layer by complexation through both pyridyl nitrogen atoms (Film I). Photoexcitation of the film in chloroform at 300 nm leads to substantial cis-trans isomerization as indicated by conductivity, impedance, grazing incidence IR, and contact angle measurements. The latter show a decrease in contact angle (increase in wettability) of 17°, which is attributed to exposure of both the underlying Cu(II) layer and one of the pyridyl ring nitrogen atoms following isomerization to the trans isomer. Copyright
A new bis-tetraamine ligand with a chromophoric 4-(9-anthracenyl)-2,6- dimethylpyridinyl linker for glyphosate and ATP sensing
Pouessel, Jacky,Abada, Sabah,Le Bris, Nathalie,Elhabiri, Mourad,Charbonnière, Lo?c J.,Tripier, Rapha?l
, p. 4859 - 4872 (2013)
The synthesis of a new linear bis-tetraamine ligand L1, based on two 1,4,8,11-tetraazaundecane units grafted at the 2 and 6 positions of a pyridinyl linker substituted by an anthracenyl fluorophore in the para position, is described and anion complexation studies of L1 with anionic substrates are reported. The protonation pattern and the study of the binding properties of L1 in an aqueous medium with two anionic substrates, the nucleotide adenosine triphosphate (ATP) and the herbicide glyphosate (N-(phosphonomethyl)glycine, PMG), were investigated by means of potentiometry, NMR spectroscopy and absorption and emission spectroscopic techniques. To decipher the impact of the chromophoric linker on the complexation process and to highlight its optical properties, a comparison is established with its previously reported analog L2 devoid of the anthracenyl group. The results unambiguously show that the protonation and complexation properties are preserved despite the presence of the bulky linker, allowing for the use of L1 as a fluorescent sensor for ATP and PMG.
Stable polymer micelles formed by metal coordination
Wang, Junyou,Cohen Stuart, Martien A.,Van Der Gucht, Jasper,Marcelis, Antonius T. M.,Colomb-Delsuc, Mathieu,Otto, Sijbren
, p. 7179 - 7185,7 (2012)
Metal-containing polymer micelles have attracted much attention due to their potential for medical and nanotechnological applications. In this paper, we present a method to prepare stable metal-containing polymer micelles. A diblock copolymer poly(4-vinylpyridine)-b-poly(ethylene oxide) (P4VP 48-b-PEO193) with terdendate ligand groups grafted to the PVP block is synthesized. Added metal ions cross-link the ligand-carrying blocks together, while the hydrophilic block stabilizes the formed coordination complex, leading to the formation of micelles. The structure and stability of the formed micelles are investigated by light scattering and cyro-TEM. The strong coordination bonds provide high stability of the micelles: adding salt or EDTA hardly affects the formed micelles.
A versatile ditopic ligand system for sensitizing the luminescence of bimetallic lanthanide bio-imaging probes
Chauvin, Anne-Sophie,Comby, Steve,Song, Bo,Vandevyver, Caroline D.B.,Buenzli, Jean-Claude G.
, p. 1726 - 1739 (2008)
The homoditopic ligand 6,6′-[methylenebis(1-methyl-1H-benzimidazole- 5,2-diyl)]bis(4-{2-[2-(2-methoxyethoxy)ethoxy]ethoxy}pyridine-2-carboxylic acid) (H2LC2) has been tailored to self-assemble with lanthanide ions (LnIII), which results in the formation of neutral bimetallic helicates with the overall composition [Ln2(L C2)3] and also provides a versatile platform for further derivatization. The grafting of poly(oxyethylene) groups onto the pyridine units ensures water solubility, while maintaining sizeable thermodynamic stability and adequate antenna effects for the excitation of both visible- and NIR-emitting LnIII ions. The conditional stability constants (log β23) are close to 25 at physiological pH and under stoichiometric conditions. The ligand triplet state features adequate energy (0-phonon transition at ≈ 21 900 cm-1) to sensitize the luminescence of EuIII (Q = 21%) and TbIII (11%) in aerated water at pH 7.4. The emission of several other VIS- and NIR-emitting ions, such as SmIII (Q = 0.38%) or YbIII (0.15%), for which in cellulo luminescence is evidenced for the first time, is also sensitized. The EuIII emission spectrum arises from a main species with pseudo-D 3 symmetry and without coordinated water. The cell viability of several cancerous cell lines (MCF-7, HeLa, Jurkat and 5D10) is unaffected if incubated with up to 500 μM [Eu2(LC2)3] during 24 h. Bright EuIII emission is seen for incubation concentrations above 10 μM and after a 15-minute loading time; similar images are obtained with TbIII and SmIII. The helicates probably permeate into the cytoplasm of HeLa cells by endocytosis. The described luminescent helical stains are robust chemical species which remain undissociated in the cell medium and in presence of other complexing agents, such as edta, dtpa, citrate or L-ascorbate. Their derivatization, which would open the way to the sensing of targeted in cellulo phenomena, is currently under investigation.
