Table 1.

The ¹H-NMR chemical shifts of bridging proton in various isotopologs of homodimers and heterodimers of POOH-containing acids 1–4 in CDF₃/CDF₂Cl at 100 K. The corresponding spectra are shown in Figure 3, Figure 5, Figure 7, Figure 9 and Figure 10 and Figures S1, S3, S5, S8, and S9.

Complex	HH	HD
1-1a	13.75	13.43
2-2b	13.33	13.02
3-3c	n.d. d	n.d.
4-4a	12.75	12.47
1-2	13.80	13.69
1-3	n.d.	n.d.
1-4	14.93	15.00
2-3	15.10	14.82
2-4	13.74	n.m. e
3-4	15.08	n.d.

^a—chemical shifts coincide with those reported previously in reference [15]. ^b—chemical shifts coincide with those reported previously in reference [14]. ^c—the diphenylphosphinic acid 3 is poorly soluble in CDF₃/CDF₂Cl and does not form self-associates in a detectable amount. ^d—n.d.—not detected. ^e—n.m.—not measured.