Host–Guest Chemistry in the Hexanuclear (Arene)ruthenium Metalla‐Prismatic Cage [Ru6(p‐cymene)6(tpt)2(dhnq)3]6+

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.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)