Guest and solvent modulated photo-driven charge separation and triplet generation in a perylene bisimide cyclophane

Cofacial positioning of two perylene bisimide (PBI) chromophores at a distance of 6.5 Å in a cyclophane structure prohibits the otherwise common excimer formation and directs photoexcited singlet state relaxation towards intramolecular symmetry-breaking charge separation (τCS = 161 ± 4 ps) in polar CH2Cl2, which is thermodynamically favored with a Gibbs free energy of ΔGCS = -0.32 eV. The charges then recombine slowly in τCR = 8.90 ± 0.06 ns to...