- 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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- 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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- Structural effect of amphiphilic crown ether azoprobes on alkali metal ion recognition and aggregation behavior in water
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Amphiphilic azoprobes having a crown ether moiety (15C5-Azo-Cn; n = 4, 6, 8, and 12 and 18C6-Azo-Cn; n=4, 6, and 8) were synthesized. We examined the effect of alkyl spacer length of the amphiphilic azoprobes on the spectral response to alkali metal ions in water by UV-vis spectral and 1HNMR measurements. 15C5-Azo-Cn exhibited self-assembly in response to K+ selectively and the most selective response to K+ was observed for an azoprobe possessing a hexyl spacer unit (15C5-Azo-C6). 15C5-Azo-C12 formed nano-size aggregates. 18C6-Azo-Cn (n = 6 and 8) showed Cs+ selectivity and its molecular aggregation behavior was similar to that of 15C5-Azo-Cn.
- Sato, Fuyuki,Tsukano, Miki,Sakamoto, Koki,Umemoto, Wakako,Hashimoto, Takeshi,Hayashita, Takashi
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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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supporting information
p. 15653 - 15660
(2021/10/01)
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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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supporting information
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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- 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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- 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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- 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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- Benzocrown Derivatives as Ionophores for Alkali Cations, III.- Synthesis of Ring-Cleaved Analogues of Benzocrown Ethers.- A Novel Method for Building Up Crown Ether Rings
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Several ring-cleaved analogues (9, 11a,b) of bis(benzo-15-crown-5)-urethanes (1a,b) were prepared to study the change of complexation by electroanalytical methods.The syntheses of the title compounds (9, 11a,b) were accomplished in two ways: starting from 4-nitroveratrole (2) via intermediates 3-8 to give compound 9 and by alkaline hydrolytic cleavage of 4-nitrobenzocrown ethers (10a,b), then by subsequent steps yielding 11a,b.
- Toeke, Laszlo,Bitter, Istvan,Agai, Bela,Hell, Zoltan,Lindner, Ernoe,et. al.
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p. 761 - 764
(2007/10/02)
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- NUCLEOPHILIC RING CLEAVAGE OF CROWN ETHERS, NOVEL METHOD FOR BUILDING UP CROWN ETHER RINGS
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The crown ether rings in 4-nitrobenzo-15-crown-5 and -18-crown-6 are cleaved by aqueous alkali affording long chain substituted pyrocatechols which proved to be good starting material for constructing crown ether rings other than the original one.
- Agai, Bela,Bitter, Istvan,Hell, Zoltan,Szoelloesy, Aron,Toeke, Laszlo
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p. 2705 - 2708
(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. 4. Influence of Alkali Metal Cations on Photoisomerization and Thermal Izomerization of Azobis(benzocrown ether)s
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Five photoresponsive azobis(benzocrown ether)s 1(4,4), 1(5,5), 1(6,6), 2(5,5) and 2(6,6), were synthesized, where numbers in parentheses denote the number of oxygens in benzocrown ethers, and crown series 2 have two tert-butyl groups in the 2 and 2' position of the azo linkage.We have found that (i) in the presence of alkali metal cations, the concentration of cis isomers (cis percent) under the photostationary state is enhanced and the rate of thermal cis-to-trans isomerization (k) is supressed, the optima cis-1(5,5) and cis-1(6,6) being observed for Rb+ and Cs+, respectively, (ii) Rb+ and Cs+ are extracted most efficiently from an aqueous solution to an organic phase (o-dichlorobenzene) with cis-1(5,5) and cis-1(6,6), respectively, (iii) cis percent and k of 2(5,5) and 2(6,6) are affected by alkyli metal cations smaller than those of corresponding 1(5,5) and 1(6,6), and (iv) cis percent and k of 1(4,4) are less affected by added alkali metal cations and the extractability is very low.The increase in cis percent and the supression of the thermal isomerization rate are rationalized in terms of the "tying effect" of complexed cations requiring the additional energy to disrupt the crown-cation interaction.The correlation of the extractability with cis percent and k implies that alkali metal cations are extracted under photoirradiation as intramolecular 1:2 cation/crown complexes and the ion selectivity is associated with the fitness between the ion size and the size of the spatial cavity provided by two crown ethers of cis form.The ion selectivity suggests (i) the cavity size of cis-1(6,6) is greater than that of cis-(5,5) and (ii) the cavity sizes of crown series 2 are smaller than those of crown series 1 probably owing to the steric repulsion of the tert-butyl groups.Hence, the ion selectivity in the photocontrolled solvent extraction is effected by the crown ring size and the steric crowding around the azo linkage.
- Shinkai, Seiji,Ogawa, Toshiyuki,Kusano, Yumiko,Manabe, Osamu,Kikukawa, Kiyoshi,et al.
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p. 1960 - 1967
(2007/10/02)
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