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  • Publication
    Métadonnées seulement
    Designing the host-guest properties of tetranuclear arene ruthenium metalla-rectangles to accommodate a pyrene molecule
    (2010)
    Barry, Nicolas P. E.
    ;
    Furrer, Julien
    ;
    ; ;
    Cationic tetranuclear rectangular macrocyclic arene ruthenium complexes [Ru4(p-cymene)4(?-N-N)2(?-dhnq)2](CF3SO3)4 [1-3, dhnq = 5,8-dihydroxy-1,4-naphthoquinonato(2-); N-N = pyrazine, 4,4'-bipyridine, 1,2-bis(4-pyridyl)ethene], featuring Ru-dhnq-Ru-N-N-Ru-dhnq-Ru rectangle structures with adjustable Ru-Ru distances (7.0 Ã…, 11.2 Ã…, 13.6 Ã…, resp.), are obtained in methanol from the reaction of the dinuclear arene ruthenium precursor [Ru2(p-cymene)2(dhnq)2Cl2] with pyrazine or bipyridine linkers in the presence of AgCF3SO3. All complexes 1-3, isolated in good yield as triflate salts, have been characterized by NMR and IR spectroscopy. The interaction of these rectangular complexes with pyrene as a guest mol. has been studied in soln. by various NMR techniques (1D, DOSY, ROESY). In CD3CN, the pyrazine-contg. metalla-rectangle 1 shows no meaningful interactions with pyrene. On the other hand, the 4,4'-bipyridine- and 1,2-bis(4-pyridyl)ethylene-contg. metalla-rectangles 2 and 3 clearly interact with pyrene. DOSY measurements suggest that, in the case of the 4,4'-bipyridine complex 2, the interactions occur on the outside of the rectangular assembly, while in the case of dipyridylethylene complex 3 the pyrene mol. is found inside the hydrophobic cavity of the metalla-rectangle, thus giving rise to a host-guest system. [on SciFinder(R)]