MP-5 and free bipy (2.3 µmole) were dissolved in 600 µL of D2O:MeOD (1:1) (v/v). Iron triflate (4.6 µmole) was dissolved in 180 µL of deuterated solvent. Stoichiometry: (1:1:1). Arrow indicates increase in the equivalents of metal added: 0, 0.14, 0.28, 0.42, 0.56, 0.7, 0.84, 0.98, 1.12, 1.26, 1.4, corresponding to the spectra labeled 1 to 10, respectively.