摘要
Complexes [(NO) 2 Fe(S- t Bu) 2 ] - (3-Na) and [Fe 2 (μ-S t Bu) 2 (NO) 4 ] (1) are in dynamic equilibrium in the protic solvent MeOH. The subsequent addition of the equivalent of cobaltocene into the MeOH solution mixture of complexes 3-Na and 1 led to the formation of the fully delocalized mixed-valence [Fe(μ-S- t Bu)(NO) 2 ] 2 - (2) characterized by IR, UV-vis, EPR, SQUID, and single-crystal X-ray diffraction. The EPR spectrum of complex 2 displaying an axial signal at g ⊥ = 2.009, g∥ = 1.965 (77 K) and an isotropic signal at g = 1.998 (298 K), identical to the EPR spectra of reduction of dinitrosyl iron complex (DNIC)/aconitase obtained from nitrosylation of aconitase and reduction of HiPIP-containing protein-bound DNIC, suggests that the [4Fe-4S] 2+ clusters of aconitase/HiPIP were nitrosylated to produce a mixture of the monomeric and dimeric DNICs. Copyright © 2007 American Chemical Society.