Figure 2a: pH dependence of the chemical shifts of the aquo coordinated ruthenium species and determination of the pKa in the following complexes [1] - Red circles; [2] - Blue squares; [3] - Pink triangles; [4] - black circles; [10] - Green squares; [11] - Orange triangles. 19F chemical shifts of the 5,5’-difluorobipyridyl fluorines or 1H chemical shift of the coordinated benzene ligand were plotted against pD. The lines are a least squares fit to an equation involving a single titratable group. Figure 2b: A series of 19F{1H} decoupled spectra of complex [1] in D2O phosphate buffer at differing pD values (2 mM Ru, 298 K). Figure 2c: The pKa values of a series of ruthenium complexes measured using (where applicable) both 19F{1H} NMR and 1H NMR. (a) – Unable to measure pKa from data collected. (b) – No fluorine atoms present in complex.
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