- Novel functionalised imidazo-benzocrown ethers bearing a thiophene spacer as fluorimetric chemosensors for metal ion detection
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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
- Esteves, Cátia I.C.,Batista, Rosa M.F.,Raposo, M. Manuela M.,Costa, Susana P.G.
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- Supramolecular dendrimer chemistry: Using dendritic crown ethers to reversibly generate functional assemblies
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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.
- Dykes, Graham M.,Smith, David K.
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- The bis-barium complex of a butterfly crown ether as a phototunable supramolecular catalyst
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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.
- Cacciapaglia, Roberta,Di Stefano, Stefano,Mandolini, Luigi
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- Salt-solubilization and ion-pair recognition by a quinoline-substituted crown ether
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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
- Sun, Zhan-Hu,Pan, Fang-Fang,Triyanti,Albrecht, Markus,Raabe, Gerhard
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- Light-Driven Molecular Motors Boost the Selective Transport of Alkali Metal Ions through Phospholipid Bilayers
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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.
- Barboiu, Mihail,Gavat, Odile,Giuseppone, Nicolas,Huang, Li-Bo,Moulin, Emilie,Wang, Wen-Zhi,Zheng, Shao-Ping
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p. 15653 - 15660
(2021/10/01)
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- Tripodal, squaramide‐based ion pair receptor for effective extraction of sulfate salt
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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
- Jagleniec, Damian,Romański, Jan,Wilczek, Marcin
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- Cooperative Transport and Selective Extraction of Sulfates by a Squaramide-Based Ion Pair Receptor: A Case of Adaptable Selectivity
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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.
- Dobrzycki, ?ukasz,Karbarz, Marcin,Romański, Jan,Wilczek, Marcin,Zaleskaya, Marta
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p. 13749 - 13759
(2020/10/05)
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- Ion-pair induced supramolecular assembly formation for selective extraction and sensing of potassium sulfate
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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
- Jagleniec, Damian,Dobrzycki, ?ukasz,Karbarz, Marcin,Romański, Jan
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p. 9542 - 9547
(2019/11/11)
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- Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
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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.
- Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
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supporting information
p. 563 - 567
(2017/01/18)
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- Synthesis of actinomycin analogs: XXIV. Non-symmetric derivatives of actinocin containing benzo-18-crown-6 moiety and tertiary ammonium group
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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.
- Ovchinnikov,Ponyaev
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p. 2612 - 2615
(2017/03/22)
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- Synthesis and Cation Recognition Study of Novel Benzo Crown Ether Functionalized Enamine Derivatives
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A novel series of benzo crown ether (dibenzo 18-crown-6 ether, benzo 18-crown-6 ether, and benzo 15-crown-5 ether) functionalized enamines derivatives from amino benzo crown ether (4-amino dibenzo 18-crown-6 ether, 4-amino benzo 18-crown-6 ether, 4-amino
- Patil, Dayanand R.,Chandam, Dattatraya R.,Mulik, Abhijeet G.,Jagdale, Suryabala D.,Patil, Prasad P.,Deshmukh, Madhukar B.
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p. 1902 - 1911
(2015/08/03)
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- Supramolecular assembly of isocyanorhodium(i) complexes: An interplay of rhodium(i)···rhodium(i) interactions, hydrophobic-hydrophobic interactions, and host-guest chemistry
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A series of tetrakis(isocyano)rhodium(I) complexes with different chain lengths of alkyl substituents has been found to exhibit a strong tendency toward solution state aggregation upon altering the concentration, temperature and solvent composition. Temperature- and solvent-dependent UV-vis absorption studies have been performed, and the data have been analyzed using the aggregation model to elucidate the growth mechanism. The aggregation is found to involve extensive Rh(I)···Rh(I) interactions that are synergistically assisted by hydrophobic-hydrophobic interactions to give a rainbow array of solution aggregate colors. It is noted that the presence of three long alkyl substituents is crucial for the observed cooperativity in the aggregation. Molecular assemblies in the form of nanoplates and nanovesicles have been observed in the hexane-dichloromethane solvent mixtures, arising from the different formation mechanisms based on the alkyl chain length of the complexes. Benzo-15-crown-5 moieties have been incorporated for selective potassium ion binding to induce dimer formation and drastic color changes, rendering the system as potential colorimetric and luminescent cation sensors and as building blocks for ion-controlled supramolecular assembly.
- Chan, Alan Kwun-Wa,Wong, Keith Man-Chung,Yam, Vivian Wing-Wah
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p. 6920 - 6931
(2015/06/16)
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- Efficient synthetic supramolecular channels and their light-deactivated ion transport in bilayer lipid membranes
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Inspired by the critical role of ion channel proteins in the regulation of cellular activities, here we developed a new type of synthetic ion channel by simple benzocrown ether-based derivatives M1 and M2, where M1 had a dodecyl tail and M2 had a diethylene glycol-conjugated dodecyl tail. Being amphiphilic in nature, the two small molecules were assumed to form crown ether channels through supramolecular interactions in bilayer lipid membranes (BLMs). The efficient ion transport was investigated by both a fluorescence-based vesicle assay and a planar bilayer conductance measurement, and M2 with diethylene glycol substitution exhibited more efficient activity comparable to amphotericin B. Moreover, the presence of a photosensitive o-nitrobenzyl group provided the light-regulation to deactivate ion transport by destroying the channel assembly of the molecules in BLMs, which provides new opportunities for developing intelligent light-regulated systems for biomedical applications based on synthetic small molecules.
- Bao, Chunyan,Ma, Meixin,Meng, Funa,Lin, Qiuning,Zhu, Linyong
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supporting information
p. 6297 - 6302
(2015/08/06)
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- Light-controlled ion channels formed by amphiphilic small molecules regulate ion conduction via cis-trans photoisomerization
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Light-regulated ion channel-transport across lipid bilayers was realized using structurally simple azobenzene-based amphiphilic small molecules. UV or visible irradiation triggers molecular photoisomerization, which induces structural and membrane affinity changes in self-assembled channels, thus resulting in light-regulated ion transmembrane transport.
- Liu, Tao,Bao, Chunyan,Wang, Haiyan,Lin, Yao,Jia, Huijuan,Zhu, Linyong
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supporting information
p. 10311 - 10313
(2013/10/22)
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- Controlled release using mesoporous silica nanoparticles functionalized with 18-crown-6 derivative
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Mesoporous silica nanoparticles were functionalized with an 18-crown-6 group as a gate molecule and the releasing capacity as a drug delivery system was controlled by the exchange reaction of "host-guest complex" with alkaline metal ions.
- Choi, Young Lan,Jaworski, Justyn,Seo, Moo Lyong,Lee, Soo Jin,Jung, Jong Hwa
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supporting information; experimental part
p. 7882 - 7885
(2011/12/03)
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- Synthesis, X-ray diffraction and optical spectral study of benzo-18-crown-6 containing monoazo dyes
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The 4-nilrobenzo-18-crown-6, 2 have been reduced by the Fe/HCI to give 4'-aminobenzo-l8-crown-6, 3. This is diazotized and coupled with different phenols to give the corresponding azo- dyes. X-ray diffraction as well as UV-Vis study of 4' (P naphthol azo benzo) 18-crown-6, 4a dye have been reported.
- Deshinukh,Alasundkar,Salunkhc,Salunkhe,Sankpal,Patil,Anbhule
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experimental part
p. 737 - 740
(2009/12/24)
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- CROWN ETHER-DERIVATISED PERYLENES
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Perylenes of formula (I) wherein R is (a), (b), unsubstituted quinolyl, anthrolinyl or phenanthrolinyl or substituted quinolyl, anthrolinyl or phenanthrolinyl, wherein m is an integer from 0 to 4 and n is an integer from 1 to 9, and the radicals R t
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- tGENTS AND METHODS FOR THE TREATMENT OF DISORDERS ASSOCIATED WITH OXIDATIVE STRESS
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The invention provides a method for preventing or reducing the effects of oxidative stress on a substrate. The method includes the step of treating the substrate with a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein: R1 is one or more substituents selected from -H, -alkyl, -alkoxy, -aryl, -aryloxy, -halogen, -amino (mono-, di- and tri-substituted), -alkylthio, -NO2, -COOH, -COOAlkyl, -CO-alkyl, -CN; R2 is one or more substituents selected from -H, -alkyl, -(CH2CH2O)n-R5, a sugar moiety; R3 is -H, -alkyl, -aryl, -alkylOR6 , -alkylC(O)R6; R5 is selected from -H, -alkyl, -aryl; and R4 and R6 are independently selected from -OH, -O-alkyl, -O-polyalkyleneoxy, -O-aryl, -OC(O)O-alkyl, -S-alkyl and -amino.
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- Supramolecular crown ether probe/γ-cyclodextrin complex sensors for alkali metal ion recognition in water
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Crown ether probes C3-12C4 and C3-18C6, in which the pyrenyl moieties as fluorophore and benzo-12-crown-4 or benzo-18-crown-6 acting as ion recognition sites are connected by a trimethylene spacer, have been synthesized. Their supramolecular function for alkali metal ion sensing in water is compared with that of the previously designed C3-15C5/γ-CyD complex sensor. The C3-12C4, C3-15C5, and C3-18C6 are found to selectively form 2:1 complexes with Na+, K+, and Cs+, respectively, in the presence of γ-CyD and to exhibit pyrene dimer emission in water. These results demonstrate that the selectivity of the crown ether probe/γ-CyD complexes can be tuned by simply altering their crown ether ring size. The apparent 2:1 binding constants of the probes with alkali metal ions are determined at the optimum γ-CyD concentrations for each probe. For C3-12C4/γ-CyD complex, the accurate binding constant could not be obtained due to the relatively large deviation for the response. However, the fitting curve reveals that the binding constant is about 107 M-2. The 2:1 binding constants of the C3-15C5/γ-CyD complex for K+ and C3-18C6/γ-CyD complex for Cs+ are (3.8 ± 1.3) x 109 M-2 and (5.8 ± 4.6) x 107 M-2, respectively. These values are considerably larger than those of the corresponding benzocrown ethers in organic solvents. In the suparamolecular sensing system, the dimer formation of the probes inside the γ-CyD is selectively promoted by alkali metal ion binding in water. This is a novel sensing mechanism in which the dynamic molecular recognition events are successfully utilized for ion sensing in water.
- Yamauchi, Akiyo,Hayashita, Takashi,Kato, Ayako,Teramae, Norio
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p. 1527 - 1532
(2007/10/03)
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- Gas-chromatographic studies using glass capillary columns with crown-ether type stationary phases. I β-naphthol-azo-crown ethers and related compounds: Synthesis and properties
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Azoderivatives containing residues of benzo-15-crown-5 or benzo-18-crown-6 and 2-naphthol were synthesised in order to be employed as stationary phase in GC studies with glass capillary columns. Analogous azo compounds containing anisole, veratrole and phenyl residues were used for comparison. The compounds were characterised by UV-VIS, NMR and DSC measurements.
- Luca, Constantin,Spafiu, Florica,Cǎproiu, Miron Teodor,Tudor, Ecaterina,Ioni?ǎ, Petre,Constantinescu, Titus,Dǎnescu, Mihaela,Stǎnciuc, Andreea
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p. 287 - 293
(2007/10/03)
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- Synthesis of Actinomycin Analogs. XXI. Benzocrown-4'ylcarbamoylalkylamides of Actinocin
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As compounds modeling actinomycin D derivatives of actinocin were prepared containing benzo-15-crown-5 and benzo-18-crown-6 with crown moiety linked to the heterocyclic chromophore via rests of glycine, β-alanine, and ε-aminocaproic acid.
- Glibin,Ovchinnikov,Plekhanova
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p. 1494 - 1497
(2007/10/03)
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- Synthesis of Actinomycin Analogs. XX. Actinocin Amides Containing Crown-Ether Moieties
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Actinocin diamides containing benzo-15-crown-5 and benzo-18-crown-6 moieties in the amido group have been synthesized as models of Actinomycin D.
- Glibin,Plekhanova,Ovchinnikov,Korshunova
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p. 387 - 389
(2007/10/03)
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- Highly preorganized bis(benzocrown ether)s for the binding of metal ions
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Several bis(crown ethers)s consisting of benzo-12-crown-4, benzo-15-crown-5, and benzo-18-crown-6, were prepared and their complexation properties with Na+ and K+ were determined by the liquid-liquid extraction method. The remarkable 'biscrown effect' was observed in the extractions of both Na+ and K+ using bis(benzo-12-crown-4) and bis(benzo-15-crown-5). Unsymmetrical bis(crown ether)s also exhibit much higher extractabilities of both Na+ and K+ than the corresponding mono(benzocrown ether)s.
- Jeong, Kyu-Sung,Pyun, Seung Yup
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p. 7041 - 7044
(2007/10/02)
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- Photoresponsive Crown Ethers. Part 14. Photoregulated Crown-Metal Complexation by Competitive Intramolecular Tail(Ammonium)-biting
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New photoresponsive crown ethers (1H+) having a crown ether ring and an ammoniumalkyl +-(CH2)n, n = 4,6,10> group attached to the two sides of an azobenzene have been synthesized.These photoresponsive 'tail-biting' crown ethers have been designed so that intramolecular 'biting' of the ammonium group to the crown can only occur upon photoisomerisation to the cis-forms.In the thermal cis-trans isomerisation, the first-order rate constants for cis-(1H+) were smaller by 1.6 - 2.2 -fold than those for (1) (the analogous free amines).Moreover, this rate increased with increasing added K+ concentration.This suggests that the ammonium tail is intramolecularly bound to the crown ether ring in cis-(1H+).This intramolecular 'biting' is further reflected in the relative affinities of (1H+) for alkali-metal cations.The affinities were markedly reduced by u.v.-light irradiation and in particular, cis-(1H+)(n=6) and cis-(1H+)(n=10) showed almost no metal-binding ability.This marked difference in the metal-binding ability was used to generate the light-controlled systems for the passive or active ion-transport of ions across a liquid membrane.
- Shinkai, Seiji,Ishihara, Midori,Ueda, Kaori,Manabe, Osamu
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p. 511 - 518
(2007/10/02)
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- SYNTHESIS OF NITRO AND AMINO DERIVATIVES OF THE MACROCYCLIC POLYETHER 2,3-BENZO-1,4,7,10,13,16-HEXAOXACYCLOOCTADEC-2-ENE
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Convenient methods were developed for the synthesis of 1,2-di(2-hydroxyethoxy)benzene, 1,2-di(2-hydroxyethoxy)-4-nitrobenzene, and 1,2-di(2-hydroxyethoxy)-4,6-dinitrobenzene - the intermediate products in the synthesis of nitro and amino derivatives of 2,3-benzo-1,4,7,10,13,16-hexaoxacyclodec-2-ene (benzo-18-crown-6).The effect of the nature of the solvent on the yield of mono- and dinitro derivatives of 1,2-di(2-hydroxyethoxy)benzene in the nitration of the latter was investigated.It was shown that benzo-18-crown-6 and dicyclohexyl-18-crown-6 have a catalytic effect on the yield of the products from O-alkylation of 1,2-dihydroxybenzene and its derivatives.
- Abakumova, N. I.,Kolenko, I. K.,Kodess, M. I.
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p. 1305 - 1307
(2007/10/02)
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- Photoresponsive Crown Ethers. 5. Light-Driven Ion Transport by Crown Ethers with a Photoresponsive Anionic Cap
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Three photoresponsive ionophores (Cr-o, Cr-m, and Cr-p) in which benzo-18-crown-6 and a phenol group are linked with a photoisomerizable azo linkage were synthesized.On the irradiation of UV light, the azo linkage isomerized to the cis forms (46-73percent
- Shinkai, Seiji,Minami, Takahide,Kusano, Yumiko,Manabe, Osamu
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p. 1967 - 1972
(2007/10/02)
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- SYNTHESIS OF CROWN ETHER DYES.
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Crown ether dyes were synthesized in order to develop photometric reagents which are highly selective to alkali and alkaline earth metals. They contain dissociable protons attached to the chromophores of crown ether molecule. Their extraction behavior for alkali and alkaline earth metal ions as neutral complex was examined. The dyes extract potassium and alkalin earth metals, respectively. Dyes with picrylamino chromosphore are effective for extractive photometric determination of potassium. A molecular design of colorimetric reagents is discussed on the basis of crown ethers.
- Yamashita,Nakamura,Takagi,ueno
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p. 1550 - 1554
(2007/10/02)
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