Synthetic carboxyl-containing polyethers, analogs of natural antibiotics

Gardner, John O.; Beard, Colin C.

doi:10.1021/jm00202a009

Cited by 18 publications

(5 citation statements)

References 4 publications

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“…To overcome this shortcoming, we focused on conformational changes of noncyclic crown ethers from linear to helical, such as glyme and poly(ethylene glycol) derivatives, , as an alternative method since it does not require the introduction of proton-ionizable or -dissociable chromophores. Noncyclic crown ethers and related compounds have also been known as complexing reagents , for alkali-metal and alkaline-earth-metal ions and surfactants. − Most researchers, however, focus mainly on their ability as ion carriers − as in naturally occurring ionophores such as monensin. , The application of noncyclic crown ethers in oriented analytical utilization has been relatively limited. In this context, recently, we have been studying the complexation behavior of noncyclic crown ether derivatives bearing several symmetric and asymmetric fluorophores at their terminals. − This large conformational change upon complexation can transduce into a fluorometric signal.…”

Section: Introductionmentioning

confidence: 99%

“…Noncyclic crown ethers and related compounds have also been known as complexing reagents 22,23 for alkali-metal and alkalineearth-metal ions and surfactants. [24][25][26] Most researchers, however, focus mainly on their ability as ion carriers [27][28][29][30][31][32][33][34][35][36] as in naturally occurring ionophores such as monensin. 37,38 The application of noncyclic crown ethers in oriented analytical utilization has been relatively limited.…”

Section: Introductionmentioning

confidence: 99%

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New Fluorescent “Off−On” Behavior of 9-Anthryl Aromatic Amides through Controlling the Twisted Intramolecular Charge Transfer Relaxation Process by Complexation with Metal Ions

2001

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New fluorophores based on linear polyether N,N′-[oxybis(3-oxapentamethylenoxy)-2-phenyl]bis(9-anthracenecarbonamide) (3) and its analogues (2 and 4) have been synthesized, and their complexation properties with various alkali-metal and alkaline-earth-metal ions were investigated by fluorescence, UV, and 1 H NMR spectroscopies. In the absence of metal ion, 2-4 showed almost no fluorescence emission (fluorescence quantum yield Φ ) 0.0003, fluorescence "off" state) since twisted intramolecular charge transfer (TICT) occurred through the amide bond. However, 2-4 demonstrated a significant increase in fluorescence intensity around 430 nm upon complexation with alkaline-earth-metal ions. In the case of 4‚Ca 2+ , a large enhancement effect on the fluorescence quantum yield (Φ ) 0.014, [Ca 2+ ]/[4] ) 5, Φ 4‚Ca 2+ /Φ free 4 ) 42, fluorescence "on" state) was observed. This "off-on" fluorescence characteristic was originated from the cooperative strong binding mode between the carbonyl group and the ethylenoxy moiety for alkaline-earth-metal ions, resulting in effective inhibition of photoinduced TICT relaxation. Fluorophores 2-4 formed a 1:1 complex (the order of the complex formation constants was Ca 2+ > Sr 2+ ≈ Ba 2+ ) and showed no considerable spectral changes upon complexation with alkali-metal ions and Mg 2+ . The 1 H NMR study on 2-4 and their complexes indicated that free 2-4 formed a helical structure. After complexation, the conformational change of 2 from a helical structure to a semicircular structure was observed. The pseudocyclic form was supported as the complex structure of 3, whereas the large conformational change of 4 was not observed after the addition of metal ions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

New Fluorescent “Off−On” Behavior of 9-Anthryl Aromatic Amides through Controlling the Twisted Intramolecular Charge Transfer Relaxation Process by Complexation with Metal Ions

2001

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“…This idea was further supported by X-ray crystal structure analysis. 12,13 Some podand derivatives incorporating ionophoric functional groups such as carboxylic acid, hydroxyl group, 14 and quinoline 15,16 located at the terminals of molecules exhibit an excellent property as metal ion carriers. These ionophores revealed a reversible conformational change between the pseudocyclic and linear structures using interactions between hydroxyl group or quinoline moiety and carboxylate anion.…”

Section: Introductionmentioning

confidence: 99%

New Fluorimetric Alkali and Alkaline Earth Metal Cation Sensors Based on Noncyclic Crown Ethers by Means of Intramolecular Excimer Formation of Pyrene

et al. 1998

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New fluorescent reagents, 2,2‘-[oxybis(3-oxapentamethyleneoxy)]-bis[N-(1-pyrenylmethyl)benzamide)] (4) and its analogues (2, 3, and 5) which have two pyrenes at the both terminals of polyoxyethylene compounds, were synthesized, and their complexation behavior with alkaline earth cations was investigated by fluorescence spectrometry, fluorescence lifetimes, and 1H NMR spectrometry. These reagents (3−5) showed strong intramolecular excimer emissions around at 480 nm in the fluorescence spectra. On the complexation with alkaline earth metal cations, the increase of monomer emission around at 400 nm accompanied by the disappearance of intramolecular excimer emission of free reagents was observed. These reagents formed a 1:1 complex, and the order of complex formation constants was Ca2+ ≅ Sr2+ > Ba2+ > Mg2+ > Li+ for all reagents. 1H NMR spectra of these complexes with alkaline earth cations suggested the helical structures of the complexes. Fluorescence spectral changes at the formation of complexes depended on the chain length of the oxyethylene moiety and metal cations. In all cases, the formation of helical structures at the complexation was supported by the 1H NMR spectra.

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“…Polyethers (5) and (6) have a quinolyl group instead of a hydroxyl group and exhibit high transport ability for , 7_Q Li .…”

Section: Ph Responsive Crown Ethersmentioning

confidence: 99%

New Developments in “Switched-On” Crown Ethers

Shinkai¹

1992

Studies in Organic Chemistry

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Synthetic carboxyl-containing polyethers, analogs of natural antibiotics

Cited by 18 publications

References 4 publications

New Fluorescent “Off−On” Behavior of 9-Anthryl Aromatic Amides through Controlling the Twisted Intramolecular Charge Transfer Relaxation Process by Complexation with Metal Ions

New Fluorescent “Off−On” Behavior of 9-Anthryl Aromatic Amides through Controlling the Twisted Intramolecular Charge Transfer Relaxation Process by Complexation with Metal Ions

New Fluorimetric Alkali and Alkaline Earth Metal Cation Sensors Based on Noncyclic Crown Ethers by Means of Intramolecular Excimer Formation of Pyrene

New Developments in “Switched-On” Crown Ethers

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