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Template-Directed Synthesis of Hexanuclear Arene Ruthenium Complexes with Trigonal-Prismatic Architecture Based on 2,4,6-Tris(3-pyridyl)triazine Ligands
Auteur(s)
Date de parution
2011
In
Organometallics, American Chemical Society (ACS), 2011/30/5/942–951
Résumé
Cationic arene ruthenium metalla-prisms of the general formula [Ru<sub>6</sub>(<i>p</i>-cymene)<sub>6</sub>(3-tpt)<sub>2</sub>(<i>OO</i>∩<i>OO</i>)<sub>3</sub>]<sup>6+</sup> (3-tpt = 2,4,6-tris(3-pyridyl)-1,3,5-triazine; OO∩OO = 5,8-dioxido-1,4-naphthoquinonato [<b>1</b>]<sup>6+</sup> or 6,11-dioxido-5,12-naphthacenedionato [<b>2</b>]<sup>6+</sup>) have been obtained from the corresponding dinuclear arene ruthenium complexes [Ru2(<i>p</i>-cymene)<sub>2</sub>(<i>OO</i>∩<i>OO</i>)Cl<sub>2</sub>] by reaction with 3-tpt, silver trifluoromethanesulfonate in the presence of an aromatic molecule (1,3,5-tribromobenzene, phenanthrene, pyrene, or triphenylene) that acts as a template. While the large template molecule triphenylene is permanently encapsulated in the metalla-prisms to give the complexes [triphenylene⊂<b>1</b>]<sup>6+</sup> and [triphenylene⊂<b>2</b>]<sup>6+</sup>, 1,3,5-tribromobenzene can be removed in toluene, thus leaving the empty cages [<b>1</b>]<sup>6+</sup> and [<b>2</b>]<sup>6+</sup>, which are isolated as their trifluoromethanesulfonate salts. In the case of the metalla-prism connected by the 5,8-dioxido-1,4-naphthoquinonato bridging ligands, the NMR spectrum reveals two isomers, <b>1a</b> and <b>1b</b>, the formation of which can be rationalized by means of multiple NMR experiments (one-dimensional, two-dimensional, ROESY, and DOSY). The empty and filled metalla-prisms, [<b>1</b>]<sup>6+</sup>, [<b>2</b>]<sup>6+</sup>, [template⊂<b>1</b>]<sup>6+</sup>, and [template⊂<b>2</b>]<sup>6+</sup>, have been characterized by NMR, UV−vis, and IR spectroscopy. The slow exchange processes of a guest molecule moving in and out of the cavity of cages [<b>1</b>]<sup>6+</sup> and [<b>2</b>]<sup>6+</sup> have been studied in solution with phenanthrene and pyrene. One-dimensional exchange spectroscopic (1D EXSY) measurements show that [phenanthrene⊂<b>1</b>]<sup>6+</sup> is in a faster exchange regime than [phenanthrene⊂<b>2</b>]<sup>6+</sup> and that phenanthrene is more easily exchanged than pyrene in cages [<b>1</b>]<sup>6+</sup> and [<b>2</b>]<sup>6+</sup>, all observations being consistent with the portal size of the cages.
Identifiants
Type de publication
journal article