摘要
Transformation of dinitrosyl iron complexes (DNICs) [(NO) 2 Fe(SR) 2 ] - (R = Et, Ph) into [4Fe-4S] clusters [Fe 4 S 4 (SPh) 4 ] 2- in the presence of [Fe(SPh) 4 ] 2-/1- and S-donor species S 8 via the reassembling process ([(NO) 2 Fe(SR) 2 ] - → [Fe 4 S 3 (NO) 7 ] - (1)/[Fe 4 S 3 (NO) 7 ] 2- (2) → [Fe 4 S 4 (NO) 4 ] 2- (3) → [Fe 4 S 4 (SPh) 4 ] 2- (5)) was demonstrated. Reaction of [(NO) 2 Fe(SR) 2 ] - (R = Et, Ph) with S 8 in THF, followed by the addition of HBF 4 into the mixture solution, yielded complex [Fe 4 S 3 (NO) 7 ] - (1). Complex [Fe 4 S 3 (NO) 7 ] 2- (2), obtained from reduction of complex 1 by [Na][biphenyl], was converted into complex [Fe 4 S 4 (NO) 4 ] 2- (3) along with byproduct [(NO) 2 Fe(SR) 2 ] - via the proposed [Fe 4 S 3 (SPh)(NO) 4 ] 2- intermediate upon treating complex 2 with 1.5 equiv of [Fe(SPh) 4 ] 2- and the subsequent addition of 1/8 equiv of S 8 in CH 3 CN at ambient temperature. Complex 3 was characterized by IR, UV-vis, and single-crystal X-ray diffraction. Upon addition of complex 3 to the CH 3 CN solution of [Fe(SPh) 4 ] - in a 1:2 molar ratio at ambient temperature, the rapid NO radical-thiyl radical exchange reaction between complex 3 and the biomimetic oxidized form of rubredoxin [Fe(SPh) 4 ] - occurred, leading to the simultaneous formation of [4Fe-4S] cluster [Fe 4 S 4 (SPh) 4 ] 2- (5) and DNIC [(NO) 2 Fe(SPh) 2 ] - . This result demonstrates a successful biomimetic reassembly of [4Fe-4S] cluster [Fe 4 S 4 (SPh) 4 ] 2- from NO-modified [Fe-S] clusters, relevant to the repair of DNICs derived from nitrosylation of [4Fe-4S] clusters of endonuclease III back to [4Fe-4S] clusters upon addition of ferrous ion, cysteine, and IscS. © 2008 American Chemical Society.