Table 3. ¹⁵N NMR chemical shift (δ) and Δδ data for complexes 4a and 4b (where Δδ = δ_free – δ_bound).

	4a	Δδ	4b	Δδ
15N equatorial Ir–N N–	326.2	–57.0	299.7	–49.9
15N equatorial Ir–N N–	390.0	6.8	360.9	11.3
15N axial Ir–N N–	305.8	–77.4	278.8	–70.8
15N axial Ir–N N–	392.2	9.0	362.8	13.2