Regioselective Synthesis and Characterization of Multinuclear Convex-Bound Ruthenium-[n]Cycloparaphenylene (n=5 and 6) Complexes

Mono- and multinuclear complexes of ruthenium and [n]cycloparaphenylene (CPP, n=5 and 6) were synthesized in excellent yields through ligand exchange of the cationic complex [(Cp)Ru(CH3CN)3](PF6) with CPP. In the multinuclear complexes, ruthenium selectively coordinated to alternate paraphenylene units to give bis- and tris-coordinated Ru complexes for [5] and [6]CPPs, respectively. Single-crystal X-ray analysis revealed the Ru was coordinated with η6-hapticity on the convex surface of CPP.