Figure 2.

(A) Structure and (B) B3LYP-D3/def2-TZVPP/ε = 4 energetics (in kcal mol^–1) of hydrogen-bonded (right) and stacked (left) binding modes of UQ in complex I. Q and SQ refer to oxidized quinone and semiquinone species, while N2[ox] and N2[red] refer to oxidized (2Fe[II]2Fe[III]) and reduced (3Fe[II]1Fe[III]) states of N2, respectively. Nonadiabatic and adiabatic eT energetics are calculated by relaxing the initial electron donor state (N2/Q) or by relaxing both the initial (N2[red]/Q) and final (N2[ox]/SQ) states, respectively.