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Photochemical [2+2] cycloaddition of the olefinic double bonds in the supramolecular rectangle [Ru<sub>4</sub>(η<sup>6</sup>-<i>p</i>-cymene)<sub>4</sub>(μ-oxalato)<sub>2</sub>(μ-4,4′-bipyridylethylene)<sub>2</sub>]<sup>4+</sup>
Auteur(s)
Barry, Nicolas P.E.
Date de parution
2009
In
Inorganic Chemistry Communications, Elsevier, 2009/12/6/465-468
Résumé
Self-assembly of 4,4′-bipyridylethylene (bpe) bidentate connector with the dinuclear arene ruthenium clip [Ru<sub>2</sub>(η<sup>6</sup>-<i>p</i>-cymene)<sub>2</sub>(μ-oxalato)Cl<sub>2</sub>] in the presence of silver triflate affords the cationic organometallic rectangle [Ru<sub>4</sub>(η<sup>6</sup>-<i>p</i>-cymene)<sub>4</sub>(μ-oxalato)<sub>2</sub>(μ-bpe)<sub>2</sub>]<sup>4+</sup> ([<b>1</b>][CF<sub>3</sub>SO<sub>3</sub>]<sub>4</sub>). Upon UV irradiation of a methanol solution of [<b>1</b>]<sup>4+</sup>, dimerisation of the olefinic double bonds of the two parallel bpe ligands occurs, thus giving rise to the [2+2] cycloaddition derivative [Ru<sub>4</sub>(η<sup>6</sup>-<i>p</i>-cymene)<sub>4</sub>(μ-oxalato)<sub>2</sub>(μ-tpcb)]<sup>4+</sup> ([<b>2</b>][CF<sub>3</sub>SO<sub>3</sub>]<sub>4</sub>) (tpcb = tetrakis(4-pyridyl)cyclobutane). The [2+2] photodimerisation reaction was followed by <sup>1</sup>H NMR spectroscopy. Moreover, the molecular structure of these two systems was deduced by one-dimensional and two-dimensional NMR experiments (<sup>1</sup>H, <sup>13</sup>C, ROESY, COSY, HSQC). These data suggest the formation of only the <i>rctt</i>-tetrakis(4-pyridyl)cyclobutane isomer.
Identifiants
Type de publication
journal article
