Voici les éléments 1 - 3 sur 3
  • Publication
    Accès libre
    Permanent Encapsulation or Host–Guest Behavior of Aromatic Molecules in Hexanuclear Arene Ruthenium Prisms
    Cationic arene ruthenium metallaprisms of the general formula [Ru6(p-cymene)6(tpt)2(OO∩OO)3]6+ {tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine; OO∩OO = 9,10-dioxo-9,10-dihydroanthracene-1,4-diolato [1]6+, 6,11-dioxo-6,11-dihydronaphthacene-5,12-diolato [2]6+} have been obtained from the corresponding dinuclear arene ruthenium complexes [Ru2(p-cymene)2(OO∩OO)Cl2] by reaction with tpt and silver trifluoromethanesulfonate. Aromatic molecules (phenanthrene, pyrene, triphenylene, coronene) present during the synthesis of these metallaprisms are permanently encapsulated to give carceplex systems. All empty cages ([1]6+ and [2]6+) and carceplex systems ([guest⊂1]6+ and [guest⊂2]6+) were isolated in good yield as trifluoromethanesulfonate salts and characterized by NMR, UV, and IR spectroscopy. The host–guest properties of [1]6+ and [2]6+ were studied in solution in the presence of small aromatic molecules (phenanthrene andpyrene). The stability constant of association (Ka) wasestimated by NMR spectroscopy for the following host–guest systems: [phenanthrene⊂1]6+, [pyrene⊂1]6+ and [phenanthrene⊂2]6+, [pyrene⊂2]6+. All Ka values were found to be larger than 2.0 × 104M–1 for these host–guest systems ([D3]acetonitrile, 21 °C).
  • Publication
    Accès libre
    Host-Guest Chemistry in the Hexanuclear (Arene)ruthenium Metalla-Prismatic Cage [Ru6(p-cymene)6(tpt)2(dhnq)3]6+
    (2009)
    Barry, Nicolas P.E.
    ;
    A large cationic triangular metalla-prism, [Ru6(p-cymene)6(tpt)2(dhnq)3]6+ ([1]6+), incorporating (p-cymene)ruthenium building blocks, bridged by 5,8-dihydroxy-1,4-naphthoquinonato (dhnq) ligands, and connected by two 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (tpt) subunits, allows encapsulation of various guest molecules. This cationic cage, isolated as its triflate salt, possesses a portal size smaller than its cavity, thus allowing both, permanent and temporary encapsulation of guest molecules. The host-guest properties of [1]6+ have been studied in solution in the presence of planar molecules [phenanthrene, pyrene, (pyren-1-ylmethyl)amine, Pt(acac)2, triphenylene]. The stability constant of association (Ka) was estimated by NMR spectroscopy for the following host-guest systems: [pyrene1]6+, [phenanthrene1]6+ and [(pyren-1-ylmethyl)amine1]6+. All Ka values were found to be larger than 2.4 × 104 M-1 for these host-guest systems ([D3]acetonitrile, 21 °C). The other two synthesised complexes, [Pt(acac)21]6+ and [triphenylene1]6+, were shown to act as carceplexes only.A large cationic triangular metalla-prism, [Ru6(p-cymene)6(tpt)2(dhnq)3]6+ ([1]6+), incorporating (p-cymene)ruthenium building blocks, bridged by 5,8-dihydroxy-1,4-naphthoquinonato (dhnq) ligands, and connected by two 2,4,6-tri(pyridin-4-yl)-1,3,5-triazine (tpt) subunits, allows encapsulation of various guest molecules. This cationic cage, isolated as its triflate salt, possesses a portal size smaller than its cavity, thus allowing both, permanent and temporary encapsulation of guest molecules. The host-guest properties of [1]6+ have been studied in solution in the presence of planar molecules [phenanthrene, pyrene, (pyren-1-ylmethyl)amine, Pt(acac)2, triphenylene]. The stability constant of association (Ka) was estimated by NMR spectroscopy for the following host-guest systems: [pyrene1]6+, [phenanthrene1]6+ and [(pyren-1-ylmethyl)amine1]6+. All Ka values were found to be larger than 2.4 × 104 M-1 for these host-guest systems ([D3]acetonitrile, 21 °C). The other two synthesised complexes, [Pt(acac)21]6+ and [triphenylene1]6+, were shown to act as carceplexes only.
  • Publication
    Accès libre
    Photochemical [2+2] cycloaddition of the olefinic double bonds in the supramolecular rectangle [Ru4(η6-p-cymene)4(μ-oxalato)2(μ-4,4′-bipyridylethylene)2]4+
    (2009)
    Barry, Nicolas P.E.
    ;
    Self-assembly of 4,4′-bipyridylethylene (bpe) bidentate connector with the dinuclear arene ruthenium clip [Ru2(η6-p-cymene)2(μ-oxalato)Cl2] in the presence of silver triflate affords the cationic organometallic rectangle [Ru4(η6-p-cymene)4(μ-oxalato)2(μ-bpe)2]4+ ([1][CF3SO3]4). Upon UV irradiation of a methanol solution of [1]4+, dimerisation of the olefinic double bonds of the two parallel bpe ligands occurs, thus giving rise to the [2+2] cycloaddition derivative [Ru4(η6-p-cymene)4(μ-oxalato)2(μ-tpcb)]4+ ([2][CF3SO3]4) (tpcb = tetrakis(4-pyridyl)cyclobutane). The [2+2] photodimerisation reaction was followed by 1H NMR spectroscopy. Moreover, the molecular structure of these two systems was deduced by one-dimensional and two-dimensional NMR experiments (1H, 13C, ROESY, COSY, HSQC). These data suggest the formation of only the rctt-tetrakis(4-pyridyl)cyclobutane isomer.