Figure 3.

(A) The EPR signal of DNIC with cysteine recorded at ambient temperature [53]. (B) The deciphering of the 13-component HFS of signal A: the triplet and the quintet HFS, respectively, from one and two nuclei of N¹⁴ (nuclear spin I = 1) of two nitrosyl ligands + additional HFS from four protons (I = 1/2) of the methylene group in two cysteine ligands of DNIC with cysteine [22]. (C) The doublet HFS of the Fe⁵⁷ nucleus (I = 1/2) in DNIC with hydroxyl ligands. The triplet HFS was identified by the hyperfine interaction of the unpaired electron with two nuclei of N¹⁵ (I = 1/2) incorporated into nitrosyl ligands of DNIC [53].