Long-Range Magnetic Interactions in <i>trans</i>-1,4-Cyclohexylene- and 1,3-Adamantylene-bis(<i>p</i>-nitrenylbenzene) by π−σ−π Hyperconjugation

Di(phenylnitrene)s linked with trans-1,4-cyclohexylene (3) and 1,3-adamantylene (4) units were generated photochemically at cryogenic temperatures. The EPR spectra are attributed to quintets. The temperature dependence of the signal intensities indicates that both quintets are thermally accessible states with energy gaps ΔE(S−Q) = 138 and 300 J mol-1, respectively. DFT calculations showed that the magnetic interactions originated in the π−σ−π hyperconjugative through-bond interactions.