Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction (Articolo in rivista)

Type

• Prodotto della ricerca (Classe)
• Articolo in rivista (Classe)

Label

• Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction (Articolo in rivista) (literal)

Anno

• 2002-01-01T00:00:00+01:00 (literal)

Alternative label

• Bartoli S. 1, Roelens S. 2 (2002)
  Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction
  in Journal of the American Chemical Society (Print)
  (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

• Bartoli S. 1, Roelens S. 2 (literal)

Pagina inizio

• 8307 (literal)

Pagina fine

• 8315 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni

• Articolo su lavoro di ricerca di interesse generale per un pubblico di ricercatori di area interdisciplinare (Chimica Supramolecolare), pubblicato su rivista di maggior prestigio dell' American Chemical Society ad elevato fattore d'impatto (IF: 6.201; fonte: ISI 2002) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

• 124 (literal)

Rivista

• Journal of the American Chemical Society (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#descrizioneSinteticaDelProdotto

• Pubblicazione Scientifica. L'articolo descrive uno studio sul riconoscimento molecolare dell'acetilcolina mediante un recettore sintetico di tipo ciclofanico, che ha messo in luce il ruolo attivo del controione nel processo di riconoscimento. L'analisi termodinamica delle energie in gioco ha chiarito l'effetto di inibizione legato alla presenza del solvente e dell'anione. Uno studio computazionale al livello di teoria DFT ha chiarito che l'inibizione dell'anione è di tipo elettrostatico e si trasmette all'interazione tra il recettore e l'acetilcolina con un meccanismo di polarizzazione. (literal)

Note

• ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

• 2 CNR - ICCOM (Firenze) (literal)

Titolo

• Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction (literal)

Abstract

• The interaction of the lipophilic cyclophane 1 with several acetylcholine (ACh) and tetramethylammonium (TMA) salts has been investigated in deuterochloroform to ascertain the influence of the counterion on the cation-pi interaction. Reliable association constants have been measured for 17 salts of commonly used anions; corresponding binding free energies -Delta G° ranged from over 8 kJ mol-1 down to the limit of detection. The dramatic dependence of the binding energy on the anion showed that the latter takes part in the process with a passive and adverse contribution, which inhibits cation binding even to complete suppression in unfavorable cases. Thermodynamic parameters for the association of 1 with TMA picrate demonstrate that binding is enthalpic in origin, showing a substantial enthalpy gain (Delta H° = -16.7 kJ mol-1) and an adverse entropic contribution (Delta S° = -27.9 J mol-1 K-1). A correlation has been found between the “goodness” of anions as binding partners and the solubility of their salts. Conversion of the anion into a more charge-dispersed species, e.g. conversion of chloride into dialkyltrichlorostannate, improves cation binding substantially, indicating that charge dispersion is a main factor determining the influence of the anion on the cation-pi interaction. DFT computational studies show that the variation of the binding free energy of TMA with the counterion is closely accounted for by the electrostatic potential (EP) of the ion-pair: guest binding appears to respond to the cation’s charge density exposed to the receptor, which is determined by the anion’s charge density through a polarization mechanism. A value of –Delta G° = 38.6 kJ mol-1 has been extrapolated for the free energy of binding of TMA to 1 in chloroform but in the absence of a counterion. The transmission of electrostatic effects from the ion-pair to the cation-pi interaction demonstrate that host-guest association is governed by coulombic attraction, as long as factors (steric, entropic, solvation, etc.) other than pure electrostatics are not prevalent. (literal)

Prodotto di

• Institute of chemistry of organometallic compounds (ICCOM) (Istituto)

Autore CNR

• STEFANO ROELENS (Persona)

Insieme di parole chiave

• Parole chiave di "Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction" (Insieme di parole chiave)

Incoming links:

Prodotto

• Institute of chemistry of organometallic compounds (ICCOM) (Istituto)

Autore CNR di

• STEFANO ROELENS (Persona)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#rivistaDi

• Journal of the American Chemical Society (Rivista)

Insieme di parole chiave di

• Parole chiave di "Binding of Acetylcholine and Tetramethylammonium to a Cyclophane Receptor: Anion?s Contribution to the Cation-pi Interaction" (Insieme di parole chiave)