Structure and thermodynamic and kinetic properties of eosin-bipyridinium complexes

Willner, Itamar; Eichen, Yoav; Rabinovitz, Mordecai; Hoffman, Ralph E.; Cohen, S.M.

doi:10.1021/ja00028a033

Cited by 50 publications

(26 citation statements)

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“…The earliest incorporation of fulgimides into biological structures was reported by Bäuerle et al [52] The carbohydrate-binding protein Concanavalin A (ConA) was chemically modified to contain a thiophenefulgimide in order to photochemically modulate binding of the substrate α-D-mannopyranoside. The synthetic attachment of the photoswitch to this protein was achieved by functionalizing a thiophenefulgimide with an Nhydroxysuccinimide (NHS) ester, which was proposed to react with lysine residues of ConA.…”

Section: Fulgimides As Photoswitches In Biological Investigationsmentioning

confidence: 99%

Fulgimides as Light‐Activated Tools in Biological Investigations

2019

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With high spatiotemporal control, the conformation, rigidity and electronics of photoresponsive bioactive molecules can be altered. This, in turn, allows for control over the biological properties of these molecules. Incorporation of a photoswitchable moiety into a number of reported inhibitors, ligands and modulators has demonstrated the ability to modulate enzyme, receptor and ion channel responses using light. To date, the major classes of photoswitches explored in biological applications have been the azobenzenes and diarylethenes. Even though the use of these photoswitches has established the value of photoresponsive molecules as biological tools, several limitations have become apparent. Fulgimides represent a promising class of photoswitches that are not widely used for such biological purposes. Their properties are similar to that of diarylethenes, as their photochromism is based on a 6π‐electrocyclic rearrangement, however, fulgimides have the added advantage of thermal stability for both isomers. Fulgimides exhibit high photostationary states and fatigue resistance, with the ability to switch in aqueous buffer solutions. In this minireview, these advantageous photophysical properties will be discussed, as well as the use of fulgimides in biological investigations.

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Section: Fulgimides As Photoswitches In Biological Investigationsmentioning

confidence: 99%

Fulgimides as Light‐Activated Tools in Biological Investigations

2019

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“…the complex between eosin and N,NЈdibenzyl-4,4Ј-bipyridinium. 15 The formation of supramolecular xanthene dye-bipyridinium complexes of variable stoichiometries and structures was also observed in solutions. 15 Transformations between kinetically favored structures and thermodynamically stable supramolecular assemblies have been reported.…”

Section: Introductionmentioning

confidence: 98%

“…15 The formation of supramolecular xanthene dye-bipyridinium complexes of variable stoichiometries and structures was also observed in solutions. 15 Transformations between kinetically favored structures and thermodynamically stable supramolecular assemblies have been reported. 15 For example, eosin and N,NЈ-dimethyl-4,4Ј-bipyridinium forms in DMF a kinet-ically favored 1:1 eosin complex that is thermally transformed into a complex where one bipyridinium unit is inter-layered between two eosin components, and a second bipyridinium is located externally to the intermolecuar assembly and acts for charge neutralization.…”

Section: Introductionmentioning

confidence: 98%

“…The complexes are stabilized by donor-acceptor interactions and cooperatively by electrostatic attractive forces. 15,16 It was shown that the xanthene dye-N,NЈ-dialkyl-4,4Ј-bipyridinium complexes in the solid state crystallize in diverse configurations. 15 Linearly stacked donor-acceptor complexes with alternate overlap positioning of the xanthene dye donor and the bipyridinium acceptor units were observed, i.e.…”

Section: Introductionmentioning

confidence: 99%

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SUPRAMOLECULAR DONOR-ACCEPTOR COMPLEXES OF DICHLOROFLUORESCEIN ANDcis- ANDtrans-4,4?-(N,N?-DIMETHYLPYRIDINIUM)ETHYLENE

Willner

Marx–Tibbon

Cohen

et al. 1997

J. Phys. Org. Chem.

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“…Wir berichten hier im Detail [22] über die K ri stallstruktur von [(PPh3)2C u (^: ^4-bPym)Cu(PPh3)2](BF4)2 H 20 • C H 3OH (1), bpym = 2,2'-Bipyrimidin, welche so wohl die Ambivalenz der K oordinationszahl von Cu(I) als auch den Beitrag kooperativer 7r/7r-Wechselwirkungen [23,24] demonstriert. Elektro chemische und ESR-Untersuchungen zur Oxida tion und Reduktion werden für eine Reihe weiterer Zweikern Verbindungen (1) berichtet:…”

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Zweikernige Bisphosphankupfer(I)-Komplexe mit dem 2,2′-Bipyrimidin-Brückenliganden: Strukturelle Analogie zu „Blauen“ Kupferzentren und Reduktion zu paramagnetischen Spezies / Dinuclear Bis(phosphane)copper(I) Complexes with 2,2′-Bipyrimidine as Bridging Ligand: Structural Analogy to “Blue” Copper Centers and Reduction to Paramagnetic Species

Vogler

Kaim

Hausen

1993

Zeitschrift Für Naturforschung B

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Dinuclear complexes [(PR3)2C u(//:/74-bpym )Cu(PR3)2](BF4)2 with the bis-chelating bridging ligand 2,2'-bipyrimidine (bpym) and various m onodentate and bidentate phosphanes were synthesized via a four com ponent "self assembly" reaction. The reversible electrochemical reduction to m onocationic radical complexes was studied by cyclic voltammetry and electron spin resonance (ESR). Highly resolved ESR spectra revealed the presence o f the bpym anion radical ligand via resolved hyperfine coupling with 'H, 14N , 31P, 63Cu and 65Cu nuclei. The variation o f phosphane ligands was accompanied by significant changes o f electrochemical potentials which were rationalized considering electronic and structural effects. The configura tional flexibility o f Cu(I) in this environment is evident from the X-ray crystal structure ana lysis o f [(PPh3)2C u(//:^4-bpym )Cu(PPh3)2](BF4)2 H2O C H 3OH for which the coordination at the metal can be described as 3 + 1 (N N'P + P'), qualitatively similar to the (NN'S + S') arrange ment around the type 1 Cu centers o f "blue" copper proteins. Intramolecular cooperative n donor/;: acceptor/^ donor "Sandwich" interactions provide parts o f the driving force for this highly distorted coordination geometry which illustrates the proclivity o f Cu(I) towards such an "entatic state" arrangement.

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Structure and thermodynamic and kinetic properties of eosin-bipyridinium complexes

Cited by 50 publications

References 3 publications

Fulgimides as Light‐Activated Tools in Biological Investigations

Fulgimides as Light‐Activated Tools in Biological Investigations

SUPRAMOLECULAR DONOR-ACCEPTOR COMPLEXES OF DICHLOROFLUORESCEIN ANDcis- ANDtrans-4,4?-(N,N?-DIMETHYLPYRIDINIUM)ETHYLENE

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