Figure 7. Broken-symmetry DFT computed Löwdin spin distributions and HFI values over four models (A, B, C and D) of the paramagnetic intermediate.

A, Depiction of the model A with Löwdin spin densities (red number) on three ¹³C nuclei (¹³C9, ¹³C8 and ¹³C10) and the bond distances (blue number) between guanidino nitrogens and Fe(II), also see Figure S15-S17 for details. B. The comparisons of spin densities and ¹⁵N_a,b HFI values of four models with the experimental parameters. The spin-projection factors calculated from the structure are K_A = 2.087, K_B = −1.087 for model A, K_A = 2.066, K_B = −1.066 for model B, and K_A = 2.019, K_B = −1.019 for model C.