A Fourfold Gold(I)−Aryl Macrocycle with Hyperbolic Geometry and its Reductive Elimination to a Carbon Nanoring Host

An ethylene glycol‐decorated [6]cyclo‐meta‐phenylene (CMP) macrocycle was synthesized and utilized as a subunit to construct a fourfold AuI2−aryl metallacycle with an overall square arrangement. The corners consist of rigid dinuclear gold(I) complexes previously known to form only triangular metallacycles. The interplay between the conformational flexibility of the [6]CMP macrocycle and the rigid dinuclear gold(I) moieties enable the square geometry, as revealed by single‐crystal X‐ray diffraction. The formation of the gold complex shows size‐selectivity compared to an alternative route using platinum(II) corner motifs. Upon reductive elimination, an all‐organic ether‐decorated carbon nanoring was obtained. Investigation as a host for the complexation of large guest molecules with a suitable convex π‐surfaces was accomplished using isothermal NMR binding titrations. Association constants for [6]cycloparaphenylene ([6]CPP), [7]CPP, C60, and C70 were determined. A conformationally flexible [6]cyclo‐meta‐phenylene derivative that can adopt a “chair” or a “boat” conformation and a rigid dinuclear gold(I) complex have been shown to form a metallacycle with a square geometry. Reductive elimination results in an all‐organic nanoring with a large inner cavity that is suitable for the supramolecular binding of several guests with convex π‐surfaces.