Figure 5.

Simulated-annealing omit map (F_obs − F_calc) calculated with Ru-F₈bp-Ad removed from F_calc. Electron density is shown at 1.65-Å resolution and contoured at 2.5 σ. For clarity only one isomer is shown. The bipyridyl ring contacts Tyr-29. Phe-193 contacts one fluorinated ring with 3.4 Å between rings, consistent with the 3.4-Å face-to-face distance observed in the benzene–hexafluorobenzene crystal structure (34). Phe-87 contacts the perfluorobiphenyl unit in an edge-on fashion, with the ɛ carbon 3.5 Å from the face of the biphenyl unit. Tyr-96 packs against the biphenyl unit in an edge-on fashion, with fluorine–carbon contacts ranging from 3.2 to 3.9 Å.