Figure 2.

Zero-field 57Fe Mößbauer spectra of (a) (iPrCNC)Fe(CH2SiMe3)2(N2) (1-Ns2(N2)), (b) (MesCNC)Fe(CH2SiMe3)2(N2) (2-Ns2(N2)), (c) (3,5-Me2MesCNC)Fe(CH2SiMe3)2(N2) (3-Ns2(N2)), (d) (tBuACNC)Fe(CH2SiMe3)2 (4-Ns2) at 80 K in the solid state. Simulated parameters (blue lines) are (a) δ = 0.13 mm/s, |ΔEQ| = 1.71 mm/s; (b) δ = 0.13 mm/s, |ΔEQ| = 1.62 mm/s; (c) δ = 0.11 mm/s, |ΔEQ| = 1.90 mm/s; (d) δ = 0.13 mm/s, |ΔEQ| = 3.89 mm/s.