Supramolecular Structures and Photoelectronic Properties of the Inclusion Complex of a Cyclic Free‐Base Porphyrin Dimer and C 60

A cyclic free‐base porphyrin dimer H 4 ‐CPD Py (CPD=cyclic porphyrin dimer) linked by butadiyne moieties bearing 4‐pyridyl groups self‐assembles to form a novel porphyrin nanotube in the crystalline state. The cyclic molecules link together through nonclassical CH⋅⋅⋅N hydrogen bonds and π–π interactions of the pyridyl groups along the crystallographic a axis. H 4 ‐CPD Py includes a C 60 molecule in its cavity in solution. In the crystal structure of the inclusion complex (C 60 ⊂H 4 ‐CPD Py ), the dimer “bites” a C 60 molecule by tilting the porphyrin rings with respect to each other, and there are strong π–π interactions between the porphyrin rings and C 60 . The included C 60 molecules form a zigzag chain along the crystallographic b axis through van der Waals contacts with each other. Femtosecond laser flash photolysis of C 60 ⊂H 4 ‐CPD Py in the solid state with photoexcitation at 420 nm shows the formation of a completely charge‐separated state {H 4 ‐CPD Py .+ +C 60 .− }, which decays with a lifetime of 470 ps to the ground state. The charge‐carrier mobility of the single crystal of C 60 ⊂H 4 ‐CPD Py was determined by flash photolysis time‐resolved microwave conductivity (FP‐TRMC) measurements. C 60 ⊂H 4 ‐CPD Py has an anisotropic charge mobility (Σ μ =0.16 and 0.13 cm 2  V −1  s −1 ) along the zigzag chain of C 60 (which runs at 45° and parallel to the crystallographic b axis). To construct a photoelectrochemical cell, C 60 ⊂H 4 ‐CPD Py was deposited onto nanostructured SnO 2 films on a transparent electrode. The solar cell exhibited photovoltaic activity with an incident photon to current conversion efficiency of 17 %.