Insight into the Dinuclear {Fe(NO)<sub>2</sub>}<sup>10</sup>{Fe(NO)<sub>2</sub>}<sup>10</sup> and Mononuclear {Fe(NO)<sub>2</sub>}<sup>10</sup> Dinitrosyliron Complexes
作者:Shih-Wey Yeh、Chih-Wei Lin、Ya-Wen Li、I-Jui Hsu、Chien-Hong Chen、Ling-Yun Jang、Jyh-Fu Lee、Wen-Feng Liaw
DOI:10.1021/ic202332d
日期:2012.4.2
The reversible redox transformations [(NO)(2)Fe(StBu)(2)](-) reversible arrow [Fe(mu-(SBu)-Bu-t)(NO)(2)](2-) reversible arrow [Fe(mu-(SBu)-Bu-t)(NO)(2)](2-) reversible arrow [Fe(mu-(SBu)-Bu-t)(NO)(2)](2) and [cation][(NO)(2)Fe(SEt)(2)] reversible arrow [cation](2)[(NO)(2)Fe(SEt)(2)] (cation = K+-18-crown-6 ether) are demonstrated. The countercation of the Fe(NO)(2)}(9) dinitrosyliron complexes (DNICs) functions to control the formation of the Fe(NO)(2)}(10)Fe(NO)(2)}(10) dianionic reduced Roussin's red ester (RRE) [PPN](2)[Fe(mu-SR)(NO)(2)](2) or the Fe(NO)(2)}(10) dianionic reduced monomeric DNIC [K+-18-crown-6 ether](2)[(NO)(2)Fe(SR)(2)] upon reduction of the Fe(NO)(2)}(9) DNICs [cation][(NO)(2)Fe(SR)(2)] (cation = PPN+, K+-18-crown-6 ether; R = alkyl). The binding preference of ligands [OPh](-)/[SR](-) toward the Fe(NO)(2)}(10) Fe(NO)(2)}(10) motif of dianionic reduced RRE follows the ligand-displacement series [SR](-) > [OPh](-). Compared to the Fe K-edge preedge energy falling within the range of 7113.6-7113.8 eV for the dinuclear Fe(NO)(2)}(9)Fe(NO)(2)}(9) DNICs and 7113.4 -7113.8 eV for the mononuclear Fe(NO)(2)}(9) DNICs, the Fe(NO)(2)}(10) dianionic reduced monomeric DNICs and the Fe(NO)(2)}(10)Fe(NO)(2)}(10) dianionic reduced RREs containing S/O/N-ligation modes display the characteristic preedge energy 7113.1-7113.3 eV, which may be adopted to probe the formation of the EPR-silent Fe(NO)(2)}(10) -Fe(NO)(2)}(10) dianionic reduced RREs and Fe(NO)(2)}(10) dianionic reduced monomeric DNICs in biology. In addition to the characteristic Fe/S K-edge preedge energy, the IRv(NO) spectra may also be adopted to characterize and discriminate [(NO)(2)Fe(mu-(SBu)-Bu-t)](2) [IRv(NO) 1809 vw, 1778 s, 1753 s cm(-1) ((KBr)], [Fe(mu-S(t)Bo)(NO)(2)](2)(-) [IRv(NO) 1674 s, 1651 s cm(-1) (KBr)], [Fe(mu-(SBu)-Bu-t)(NO)(2)](2)(2-) [IRv(NO) 1637 m, 1613 s, 1578 s, 1567 s cm(-1) (KBr)], and [K-18-crown-6 ether](2)[(NO)(2)Fe(SEt)(2)] [IRv(NO) 1604 s, 1560 s cm(-1) (KBr)].