摘要
Title full: New members of a class of dinitrosyliron complexes (DNICs): Interconversion and spectroscopic discrimination of the anionic {Fe(NO) 2 } 9 [(NO) 2 Fe(C 3 H 3 N 2 ) 2 ] - and [(NO) 2 Fe(C 3 H 3 N 2 )(SR)] - (C 3 H 3 N 2 = deprotonated imidazole; R = t Bu, Et, Ph). The anionic {Fe(NO) 2 } 9 DNIC [(NO) 2 Fe(C 3 H 3 N 2 ) 2 ] - (2) (C 3 H 3 N 2 = deprotonated imidazole) containing the deprotonated imidazole-coordinated ligands and DNICs [(NO) 2 Fe(C 3 H 3 N 2 )(SR)] - (R = t Bu (3), Et (4), Ph (5)) containing the mixed deprotonated imidazole-thiolate coordinated ligands, respectively, were synthesized by thiol protonation or thiolate(s) ligand-exchange reaction. The anionic {Fe(NO) 2 } 9 DNICs 2-5 were characterized by IR, UV-vis, EPR, and single-crystal X-ray diffraction. The facile transformation among the anionic {Fe(NO) 2 } 9 DNICs 2-5 and [(NO) 2 Fe(S t Bu) 2 ] - /[(NO) 2 Fe(SEt) 2 ] - /[(NO) 2 Fe(SPh) 2 ] - was demonstrated in this systematic study. Of importance, the distinct electron-donating ability of thiolates serve to regulate the stability of the anionic {Fe(NO) 2 } 9 DNICs and the ligand-substitution reactions of DNICs. At 298 K, DNIC 2 exhibits the nine-line EPR signal with g = 2.027 (a N(NO) = 2.20 and a N(Im-H) = 3.15 G; Im-H = deprotonated imidazole) and DNIC 3 displays the nine-line signals with g = 2.027 (a N(NO) = 2.35 and a N(Im-H) = 4.10 G). Interestingly, the EPR spectrum of complex 4 exhibits a well-resolved 11-line pattern with g = 2.027 (a N(NO) = 2.50, a N(Im-H) = 4.10 G, and a H = 1.55 G) at 298 K. The EPR spectra (the pattern of hyperfine splitting) in combination with IR ν NO spectra (Δν NO = the separation of NO stretching frequencies, Δν NO = ∼62 cm -1 for 2 vs ∼50 cm -1 for 3-5 vs ∼43 cm -1 for [(NO) 2 Fe(S t Bu) 2 ] - /[(NO) 2 Fe(SEt) 2 ] - /[(NO) 2 Fe(SPh) 2 ] _ ) may serve as an efficient tool for the discrimination of the existence of the anionic {Fe(NO) 2 } 9 DNICs containing the different ligations [N,N]/[N,S]/[S,S]. © 2008 American Chemical Society.