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Titolo:
Alkali metal cation selectivity of an oligo-ether substituted norbornadiene and quadricyclane isomer
Autore:
Herges, R; Winkler, T;
Indirizzi:
Univ Kiel, Inst Organ Chem, D-24098 Kiel, Germany Univ Kiel Kiel GermanyD-24098 l, Inst Organ Chem, D-24098 Kiel, Germany
Titolo Testata:
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
fascicolo: 23, , anno: 2001,
pagine: 4419 - 4422
SICI:
1434-193X(200112):23<4419:AMCSOA>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
LIQUID ORGANIC MEMBRANE; WATER-SOLUBLE QUADRICYCLANES; HOST-GUEST COMPLEXATION; DRIVEN ION-TRANSPORT; CROWN-ETHERS; VALENCE ISOMERIZATION; PROTON TRANSLOCATION; ACTIVE-TRANSPORT; LIGHT ENERGY; SOLAR-ENERGY;
Keywords:
isomerization; alkali metals; molecular modeling; association constants; octopus ligand;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Herges, R Univ Kiel, Inst Organ Chem, Otto Hahn Pl 4, D-24098 Kiel, Germany Univ Kiel Otto Hahn Pl 4 Kiel Germany D-24098 098 Kiel, Germany
Citazione:
R. Herges e T. Winkler, "Alkali metal cation selectivity of an oligo-ether substituted norbornadiene and quadricyclane isomer", EUR J ORG C, (23), 2001, pp. 4419-4422

Abstract

We present investigations aimed at using the norbornadiene/ quadricyclane system as a framework for a switchable cation carrier. According to molecular modelling studies a suitably substituted system should perform a pincer-like motion upon isomerisation and reisomerisation, while complexing and decomplexing a host molecule. To this end, we investigated the complexing abilities of a 1,5,6,7-tetrasubstituted quadricyclane polyether and its corresponding norbornadiene isomer. The picrate extraction method was applied to determine the extraction constants K-ex and the association constants Kris of these polyethers with alkali metal cations in chloro-form. As expected, the complexes of the quadricyclane polyether with Li+, Na+, K+ and Cs+ are more stable than those of the norbornadiene isomer. This difference reachesa maximum for potassium. The interconversion between the norbornadiene polyether and the corresponding quadricyclane was also examined. The norbornadiene can be converted photochemically to the quadricyclane with 50% conversion while the reverse reaction is catalysed by neutral aluminium oxide in 71% yield. No by-product was detected in either of the isomerization reactions.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 01:30:30