Faculté des sciences

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+

Barry, Nicolas P.E. ; Therrien, Bruno

In: Inorganic Chemistry Communications, 2009, vol. 12, no. 6, p. 465-468

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+... Plus

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    Summary
    Self-assembly of 4,4′-bipyridylethylene (bpe) bidentate connector with the dinuclear arene ruthenium clip [Ru26-p-cymene)2(μ-oxalato)Cl2] in the presence of silver triflate affords the cationic organometallic rectangle [Ru46-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 [Ru46-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.