Chromo- and fluoroionophores. A new class of dye reagents

Loehr, H.-G.; Voegtle, F.

doi:10.1021/ar00111a001

Cited by 392 publications

(68 citation statements)

References 44 publications

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“…46,52 The addition of acid to form ReAZBAP + -H + , or of metal salts to form ReAZBAP + -M n+ , results in a blue-shift in the ILCT band ( Figure 1 and Table 1; Figure S1 in Supporting Information), with the largest shift occurring on protonation. Such shifts are well-documented for chromophores linked to azacrown ethers, [23][24][25]31,36,54 and they are attributed to the interaction of the cation with the azacrown nitrogen atom increasing its oxidation potential, 46 raising the energy of the ILCT transition, and giving a shift in peak wavelength (∆λ) whose magnitude correlates broadly with the charge-to-radius 55 (z/r) ratios of the cations (Figure 1, inset). An obvious anomaly in the general trend is Li + that, despite its high z/r ratio, gives a small shift that has been attributed to this small cation binding to the four azacrown oxygen atoms and remaining relatively remote from the azacrown N-atom.…”

Section: Resultsmentioning

confidence: 87%

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex

2004

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A [(bpy)Re(CO) 3 L] + complex (bpy ) 2,2′-bipyridine) in which L contains an azacrown ether Schanze, K. S. J. Am. Chem. Soc. 1991, 113, 6108) acts as a reversible light-controlled switch of alkali and alkaline earth metal cations bound to the azacrown, as observed directly by time-resolved UV-vis spectroscopy. Excitation to the metal-to-ligand charge-transfer (MLCT) state of the metal-complexed form, [(bpy)Re(CO) 3 L] + -M n+ , results in cation release on the nanosecond time scale for M n+ ) Li + , Na + , Ca 2+ , and Ba 2+ , with Li + and Na + being released more rapidly than Ca 2+ and Ba 2+ ; by contrast, Mg 2+ is not released. After decay to the ground state, [(bpy)Re(CO) 3 L] + recaptures metal cations on the microsecond time scale to restore the starting thermal equilibrium. A multistep rebinding mechanism is observed for Li + and Na + , in which the cation attaches initially to the azacrown nitrogen atom before binding to the equilibrium position within the azacrown ring. The excited states and other intermediates in the cation release-and-recapture cycle have been observed directly in real time, and their decay rate constants have been determined as a function of cation identity, enabling a generalized light-controlled cation-switching mechanism to be developed for this generic molecular design.

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Section: Resultsmentioning

confidence: 87%

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex

2004

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“…The character of the ∆δ H plots vs. c A /c L indicates the simple complexation model for the system 2b•EtNH 3 + ClO 4 -(equilibrium 1) and as sumes two equilibria (1) and (2) for the system 2 , which were made by H 1 NMR spectroscopy and spectropho tometry, virtually coincide. The K 1 value for the complex 2a•EtNH 3 + obtained from the data of 1 H NMR titration is threefold higher than the value of this constant ob tained by spectrophotometric titration.…”

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confidence: 76%

Photosensitive molecular tweezers 3. Synthesis and homoditopic complex formation of a bisstyryl dye containing two crown-ether fragments with diammonium salts

et al. 2005

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A new molecular tweezers, viz., bisstyryl dye containing two 18 crown 6 ether moieties and one p phenylenedimethylene spacer group, was synthesized. Complex formation of this dye and a model monostyryl dye with ions EtNH 3 + and NH 3 + (CH 2 ) n NH 3 + (n = 2-6) in MeCN was studied using spectrophotometry and 1 H NMR spectroscopy. The homoditopic bisstyryl dye and diammonium salts form strong supramolecular complexes with pseudocyclic structure.The ability for self organization at the molecular level (spontaneous assembling) in solution with a selective for mation of supramolecular structures and the presence of photosensitive moieties are prerequisite for the creation of optical molecular sensors. 2-6 Among weak interatomic interactions, which play the major role in molecular self assembling involving organic substrates, a hydrogen bond is important. 7 Design of molecular sensors capable of rec ognizing substituted ammonium ions are of special inter est. 8 Crown ethers bind primary ammonium ions through three hydrogen bonds with the NH 3 + groups. 9 Diammo nium ions compose a significant group of ammonium ions, and many of them are natural compounds. The use of the two identical diaza 18 crown 6 ether moieties within macrotri and macrotetracyclic structures capable of binding NH 3 + groups made it possible to prepare homoditopic receptors that form molecular cryptates due to bonds with the terminal ammonium groups of the sub strate. 10,11 However, if the receptors contain no photo sensitive fragments, they cannot be used as optical mo lecular sensors.Bisstyryl dye 1, in which two chromogens are co valently linked by a short trimethylene chain, has at tracted our attention, because this dye was preorganized to form photosensitive sandwich like complexes with al kaline earth metal cations with large ion radii due to the cooperative effect of two crown ether fragments. 12The use of a conformationally rigid p phenylene dimethylene spacer instead of the short polymethylene chain in the crown containing bisstyryl dyes is one of the promising approaches to the creation of optical molecular sensors for rather large diammonium cations.In the present work, we report the synthesis of a crown containing bisstyryl dye of the pyridine series (2a) and the study of complex formation of this ditopic dye with sev eral oligomethylenediammonium salts by spectrophotom etry and 1 H NMR spectroscopy.Dye 2a (in the form of dibromide) was synthesized in high yield (86%) by quaternization of pyridylvinylbenzo * For Part 2, see Ref. 1.

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“…The change in dipole moment results in a Stokes shift of the fluorophore. In addition to the spectra shifts, change in quantum yields and fluorescence lifetimes are often observed [19] . It can be imagined that the interaction of analytes with the donor or the acceptor moiety would change the photophysical properties of the fluorophore because the complexed analyte can affect the efficiency of the intramolecular charge transfer process [20] .…”

Section: Photophysics Of Fluorescent Chemosensormentioning

confidence: 99%

Chemical sensors based on π-conjugated organic molecules and gold nanoparticles

Yuan

Liu

et al. 2009

Sci. China Ser. B-Chem.

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Scientists have developed techniques for synthesizing and characterizing many new materials including conjugated small molecules, polymers and gold particles protected by conjugated organic chromophores for testing specific sensing properties in the past decade. Still, the design and synthesis or supermolecular systems fabrication of novel materials with controlled sensing properties is a significant and ongoing challenge within nanoscience and nanotechnology. Recently, our group has successfully constructed a series of chemosensors using small organic molecules, conjugated polymers and gold nanoparticles for real-time detection of specific analytes. The chemosensors show high selectivity and sensitivity in the detection of cations and biologic analytes and thus are potentially promising for applications in sensing assay system. In this review, recent sutdies on the design, synthesis and photo-physical properties of novel materials and construct of chemosensors are summarized with an emphasis on the development in our groups in recent years. energy transfer, charge transfer, nanotechnology, organic-inorganic hybrid composites.

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Chromo- and fluoroionophores. A new class of dye reagents

Cited by 392 publications

References 44 publications

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex

Photosensitive molecular tweezers 3. Synthesis and homoditopic complex formation of a bisstyryl dye containing two crown-ether fragments with diammonium salts

Chemical sensors based on π-conjugated organic molecules and gold nanoparticles

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Chromo- and fluoroionophores. A new class of dye reagents

Cited by 392 publications

References 44 publications

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)3L]+ Complex

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)3L]+ Complex

Photosensitive molecular tweezers 3. Synthesis and homoditopic complex formation of a bisstyryl dye containing two crown-ether fragments with diammonium salts

Chemical sensors based on π-conjugated organic molecules and gold nanoparticles

Contact Info

Product

Resources

About

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex

Light-Controlled Ion Switching: Direct Observation of the Complete Nanosecond Release and Microsecond Recapture Cycle of an Azacrown-Substituted [(bpy)Re(CO)₃L]⁺ Complex