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Titolo:
Molecular meccano, 49 - Pseudorotaxanes and catenanes containing a redox-active unit derived from tetrathiafulvalene
Autore:
Asakawa, M; Ashton, PR; Balzani, V; Boyd, SE; Credi, A; Mattersteig, G; Menzer, S; Montalti, M; Raymo, FM; Ruffilli, C; Stoddart, JF; Venturi, M; Williams, DJ;
Indirizzi:
Univ Bologna, Dipartimento Chim G Ciamician, I-40126 Bologna, Italy Univ Bologna Bologna Italy I-40126 m G Ciamician, I-40126 Bologna, Italy Univ Birmingham, Sch Chem, Birmingham B15 2TT, W Midlands, England Univ Birmingham Birmingham W Midlands England B15 2TT W Midlands, England Univlanddon Imperial Coll Sci Technol & Med, Dept Chem, London SW7 2AY, Eng Univ London Imperial Coll Sci Technol & Med London England SW7 2AY , Eng
Titolo Testata:
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
fascicolo: 5, , anno: 1999,
pagine: 985 - 994
SICI:
1434-193X(199905):5<985:MM4-PA>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
STEREOISOMERIC 1,5-THIAZOCINE DERIVATIVES; SULFUR-NITROGEN INTERACTIONS; TEMPLATE-DIRECTED SYNTHESIS; METAL RECEPTOR SYSTEMS; TRANSITION-METAL; SUPRAMOLECULAR CHEMISTRY; INCLUSION COMPLEXATION; SELECTIVE RECOGNITION; ROTAXANES; CYCLODEXTRIN;
Keywords:
catenanes; molecular machines; pseudorotaxanes; template-directed synthesis; tetrathiafulvalenes;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
72
Recensione:
Indirizzi per estratti:
Indirizzo: Balzani, V UnivItalygna, Dipartimento Chim G Ciamician, Via Selmi 2, I-40126 Bologna, Univ Bologna Via Selmi 2 Bologna Italy I-40126 -40126 Bologna,
Citazione:
M. Asakawa et al., "Molecular meccano, 49 - Pseudorotaxanes and catenanes containing a redox-active unit derived from tetrathiafulvalene", EUR J ORG C, (5), 1999, pp. 985-994

Abstract

Two bis(2-oxy-1,3-propylenedithio)tetrathiafulvalene-containing acyclic polyethers and two macrocyclic polyethers, each incorporating one bis(2-oxy-1,3-propylenedithio)tetrathiafulvalene unit and one p-phenylene ring, have been synthesized. The two acyclic polyethers are bound by cyclobis (paraquat-p-phenylene) with pseudorotaxane geometries in solution. The two macrocyclic polyethers have been mechanically interlocked with this tetracationic cyclophane to form [2]catenanes in a kinetically controlled self-assembly process. The X-ray crystallographic analysis of one of the two [2]catenanes and H-1-NMR-spectroscopic studies of both compounds showed that the p-phenylene ring of the macrocyclic polyether is located inside the cavity of the tetracationic cyclophane, while the bis(2-oxy-1,3-propylenedithio)tetrathiafulvalene unit resides alongside. The [2]pseudorotaxanes and [2]catenanes show broad bands around 780 nm, arising from the charge-transfer (CT) interaction between the electron-donor tetrathiafulvalene(TTF-)type unit and the electron-acceptor units of the tetracationic cyclophane. H-1-NMR-spectroscopic studies have shown that the [2]pseudorotaxanes dissociate into their separate components upon oxidation of the TTF-type unit, as a result of disruption of the CT interaction and electrostatic repulsion between the tetracationic host and the newly formed monocationic guest. The subsequent reductionof the guest to its neutral state affords back the pseudorotaxane-type complex restoring the original equilibrium. The results obtained from electrochemical experiments are consistent with the reversible, redox-driven dethreading/rethreading process observed by H-1-NMR spectroscopy. Variable-temperature H-1-NMR-spectroscopic investigations have revealed two dynamic processes, both involving the relative movements of the mechanically interlocked components in the [2]catenanes. The two consecutive oxidation processes involving the TTF-type unit, observed electrochemically, are displaced toward more positive potentials compared with the free cyclic polyethers. The two reversible two-electron reduction processes, characteristic of free cyclobis(paraquat-p-phenylene), separate into four reversible one-electron processes because of the topological difference between the "inside" and "alongside" electron-acceptor units in the [2]catenane.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/01/20 alle ore 15:48:40