Zoom-in of the nitroxyl protons in the 1H NMR spectrum of 3a (CD2Cl2, 400 MHz, 20 °C).
1H NMR spectra of (i) 1, (ii) the mixture of GaCl3 and 1, and (iii) the mixture of InBr3 and 1 in CD2Cl2.
Section of the 1H-NOESY NMR spectrum of complex 1d recorded at 400.13 MHz in methylene chloride-d2 (298 K) showing the selective intramolecular interactions of the hydrides with protons H-6 and H-o.