Figure 26.

(a) Time-resolved electron paramagnetic resonance spectrum of NDI–A₃G₁–Sd at 85 K, 100 ns after a 355 nm, 7 ns laser pulse (black trace) and its simulation (red trace). (b) Out-of-phase electron spin–echo envelope modulation (OOP-ESEEM) for NDI–A₂G_n–Sd hairpins. Experimental data are shown for NDI–A₂G₂–Sd (red), NDI–A₂G₃–Sd (blue), and NDI–A₂G₄–Sd (green). Simulated echo modulations (black) used to predict the SCRP distances listed for each hairpin based on the extracted dipolar coupling constant. (c) Cartoon of NDI–A₂G₂–Sd illustrating the rotation of the Sd end-cap necessary to achieve the measured radical pair distances between NDI^•– and Sd^•+. All panels adapted with permission from ref (318). Copyright 2019 American Chemical Society.