摘要
The synthesis, characterization, and transformation of the anionic {Fe(NO) <sub>2</sub> } <sup>9</sup> dinitrosyl Iron complexes (DNICs) [(NO) <sub>2</sub> Fe(ONO) <sub>2</sub> ] <sup>-</sup> (1), [(NO) <sub>2</sub> Fe(OPh) <sub>2</sub> ] <sup>-</sup> (2), [(NO) <sub>2</sub> Fe(OPh)(C <sub>3</sub> H <sub>3</sub> N <sub>2</sub> )] <sup>-</sup> (3) (C <sub>3</sub> H <sub>3</sub> N <sub>2</sub> =imldazolate), [(NO) <sub>2</sub> Fe(OPhX-SC <sub>4</sub> H <sub>3</sub> S)] <sup>-</sup> (4), [(NO) <sub>2</sub> Fe(P-OPhF) <sub>2</sub> ] <sup>-</sup> (5), and [(NO) <sub>2</sub> Fe(SPh)(ONO)] <sup>-</sup> (6) were Investigated. The binding affinity of ligands ([SPh] <sup>-</sup> , [-SC <sub>4</sub> H <sub>3</sub> S] <sup>-</sup> , [C <sub>3</sub> H <sub>3</sub> N <sub>2</sub> F, [OPh] <sup>-</sup> , and [NO <sub>2</sub> ] <sup>-</sup> ) toward the {Fe(NO) <sub>2</sub> } <sup>9</sup> motif follows the ligand-dlsplacement series [SPh] ~ [-SC <sub>4</sub> H <sub>3</sub> S] > [C <sub>3</sub> H <sub>3</sub> N <sub>2</sub> ] > [OPh] <sup>-</sup> > [NO <sub>2</sub> ] <sup>-</sup> . The findings, the pre-edge energy derived from the 1s → 3d transition In a distorted T <sub>d</sub> environment of the Fe center falling within the range of 7113.4-7113.8 eV for the anionic {Fe(NO) <sub>2</sub> } <sup>9</sup> DNICs, implicate that the Iron metal center of DNICs is tailored to minimize the electronic changes accompanying changes in coordinated ligands. Our results bridging the ligandsubstltution reaction study and X-ray absorption spectroscopy study of the electronic richness of the {Fe(NO) <sub>2</sub> } core may point the way to understanding the reasons for nature's choice of combinations of cysteine, histldine, and tyrosine In protein-bound DNICs and rationalize that most DNICs characterized/proposed nowadays are bound to the proteins almost through the thiolate groups of cystelnate/glutathlone side chains In biological systems. © 2009 American Chemical Society.