Template-Directed Synthesis of Hexanuclear Arene Ruthenium Complexes with Trigonal-Prismatic Architecture Based on 2,4,6-Tris(3-pyridyl)triazine Ligands

摘要

Cationic arene ruthenium metalla-prisms of the general formula [Ru(-cymene)(3-tpt)(∩)] (3-tpt = 2,4,6-tris(3-pyridyl)-1,3,5-triazine; OO∩OO = 5,8-dioxido-1,4-naphthoquinonato [] or 6,11-dioxido-5,12-naphthacenedionato []) have been obtained from the corresponding dinuclear arene ruthenium complexes [Ru2(-cymene)(∩)Cl] 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⊂] and [triphenylene⊂], 1,3,5-tribromobenzene can be removed in toluene, thus leaving the empty cages [] and [], 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, and , 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, [], [], [template⊂], and [template⊂], 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 [] and [] have been studied in solution with phenanthrene and pyrene. One-dimensional exchange spectroscopic (1D EXSY) measurements show that [phenanthrene⊂] is in a faster exchange regime than [phenanthrene⊂] and that phenanthrene is more easily exchanged than pyrene in cages [] and [], all observations being consistent with the portal size of the cages.