68941-06-0Relevant articles and documents
Novel functionalised imidazo-benzocrown ethers bearing a thiophene spacer as fluorimetric chemosensors for metal ion detection
Esteves, Cátia I.C.,Batista, Rosa M.F.,Raposo, M. Manuela M.,Costa, Susana P.G.
, p. 134 - 142 (2016)
Novel phenylalanine derivatives bearing benzimidazole and crown ethers as coordinating/reporting units and thiophene as spacer unit were synthesized, and their evaluation as fluorimetric chemosensors was carried out in acetonitrile and acetonitrile/water
Supramolecular dendrimer chemistry: Using dendritic crown ethers to reversibly generate functional assemblies
Dykes, Graham M.,Smith, David K.
, p. 3999 - 4009 (2003)
A series of crown ether derivatives functionalised with dendritic branching based on L-lysine repeat units has been synthesised. The ability of these receptors to interact with cationic guests has been investigated using NMR and mass spectrometric techniques. Binding constants have been evaluated, some using competitive binding assays, and these indicate that the strength of interaction between the encapsulated crown-ether and cationic guests decreases with increasing dendritic functionalisation. The interaction of these dendritic branches with ditopic ammonium cation functionalised templates has been investigated, and Job plot analysis indicates the formation of 2:1 (branch/template) stoichiometric complexes in MeOH solution. These supramolecular assemblies have been disassembled by the addition of potassium cations, hence achieving controlled release of the template back into solution. This process has been investigated by NMR methods and the effect of counteranion on these studies is reported. The use of ditopic ammonium cations possessing long alkyl spacer chains as templates has also been investigated, and in this case, the 2:1 assembly that forms, goes on to achieve higher order levels of organisation, hence gelating the solvent. This particular system is therefore a rare example in which discrete, characterisable dendritic supermolecules possess an inherent potential for further supramolecular assembly, to yield new materials.
The bis-barium complex of a butterfly crown ether as a phototunable supramolecular catalyst
Cacciapaglia, Roberta,Di Stefano, Stefano,Mandolini, Luigi
, p. 2224 - 2227 (2003)
Reversible phototuning of the catalytic efficiency of the bis-barium complex of azobis(benzo-18-crown-6) in the basic ethanolysis of anilide derivatives has been achieved by light-induced cis ? trans interconversion of the azobenzene spacer unit of the catalyst. The geometry of the productive catalystsubstrate complex is more favorable when the concave cis form of the catalyst is involved. Continuous photoregulation of the catalytic activity at any intermediate value between the "HIGH" and "LOW" levels was achieved by proper adjustment of the excitation wavelength or the irradiation time. The complete and relatively fast interconvertibility of photostationary states allowed the activity of the catalyst to be repeatedly photoswitched "HIGH" and "LOW" in the course of the same run.
Salt-solubilization and ion-pair recognition by a quinoline-substituted crown ether
Sun, Zhan-Hu,Pan, Fang-Fang,Triyanti,Albrecht, Markus,Raabe, Gerhard
, p. 7922 - 7932 (2013)
A novel quinoline-substituted crown ether has been synthesized as a receptor for ion pairs and its binding behavior was investigated in various solvents. The binding of ion pairs in [D6]DMSO and in mixed [D 6]DMSO/CD3CN/CD
Light-Driven Molecular Motors Boost the Selective Transport of Alkali Metal Ions through Phospholipid Bilayers
Barboiu, Mihail,Gavat, Odile,Giuseppone, Nicolas,Huang, Li-Bo,Moulin, Emilie,Wang, Wen-Zhi,Zheng, Shao-Ping
, p. 15653 - 15660 (2021/10/01)
A hydrophobic light-driven rotary motor is functionalized with two 18-crown-6 macrocycles and incorporated into phospholipid bilayers. In the presence of this molecular construct, fluorescence assays and patch clamp experiments show the formation of selective alkali ion channels through the membrane. Further, they reveal a strongly accelerated ion transport mechanism under light irradiation. This increase of the fractional ion transport activity (up to 400%) is attributed to the out-of-equilibrium actuation dynamics of the light-driven rotary motors, which help to overcome the activation energy necessary to achieve translocation of alkali ions between macrocycles along the artificial channels.
Tripodal, squaramide‐based ion pair receptor for effective extraction of sulfate salt
Jagleniec, Damian,Romański, Jan,Wilczek, Marcin
, (2021/05/28)
Combining three features—the high affinity of squaramides toward anions, cooperation in ion pair binding and preorganization of the binding domains in the tripodal platform—led to the effective receptor 2. The lack of at least one of these key elements in
Cooperative Transport and Selective Extraction of Sulfates by a Squaramide-Based Ion Pair Receptor: A Case of Adaptable Selectivity
Dobrzycki, ?ukasz,Karbarz, Marcin,Romański, Jan,Wilczek, Marcin,Zaleskaya, Marta
, p. 13749 - 13759 (2020/10/05)
The use of a squaramide-based ion pair receptor offers a solution to the very challenging problem of extraction and transport of extremely hydrated sulfate salt. Herein we demonstrate for the first time that a neutral receptor is able not only to selectively extract but also to transport sulfates in the form of an alkali metal salt across membranes and to do so in a cooperative manner while overcoming the Hofmeister bias. This was made possible by an enhancement in anion binding promoted by cation assistance and by diversifying the stoichiometry of receptor complexes with sulfates and other ions. The existence of a peculiar 4:1 complex of receptor 2 with sulfates in solution was confirmed by UV-vis and 1H NMR titration experiments, DOSY and DLS measurements, and supported by solid-state X-ray measurements. By varying the separation technique and experimental conditions, it was possible to switch the depletion of the aqueous layer into extremely hydrophilic or less lipophilic salts, thus obtaining the desired selectivity.
Ion-pair induced supramolecular assembly formation for selective extraction and sensing of potassium sulfate
Jagleniec, Damian,Dobrzycki, ?ukasz,Karbarz, Marcin,Romański, Jan
, p. 9542 - 9547 (2019/11/11)
Selective extraction of sulfates in the form of alkali metal salts using charge-neutral molecular receptors is one of the holy grails of supramolecular chemistry. Herein we describe, for the first time, a squaramide-based ion pair receptor equipped with a
Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
supporting information, p. 563 - 567 (2017/01/18)
A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
Synthesis of actinomycin analogs: XXIV. Non-symmetric derivatives of actinocin containing benzo-18-crown-6 moiety and tertiary ammonium group
Ovchinnikov,Ponyaev
, p. 2612 - 2615 (2017/03/22)
Non-symmetric derivatives of actinocin containing fragments of benzo-18-crown-6 and dimethylaminopropylamine (with the crown ether group separated from the heterocyclic chromophore by β-alanine moiety) have been prepared as models of actinomycin D.
