Cylindrical Cycloparaphenylene Triple-Decker.

The bottom-up synthesis of discrete molecular cylinders consisting of three axially aligned cycloparaphenylene (CPP) layers remains elusive. Here, we report the first synthesis and characterization of a well-defined CPP triple-decker molecule, denoted as CPP-TD, which maintains a persistent cylindrical geometry at room temperature. This structure is efficiently constructed via a concise, stereoselective cyclocondensation reaction. X-ray crystallographic analysis confirms a rigid cis-cis cylindrical conformation in the solid state, a geometry that is retained in solution as evidenced by spectroscopic studies. The observed shape persistency arises from attractive van der Waals (vdW) interactions between adjacent CPP layers. Owing to its rigid cylindrical architecture and alternating donor-acceptor constitution, CPP-TD exhibits distinctive optical properties and demonstrates strong binding affinity toward fullerene C70, forming a tight 1:2 host-guest complex.