O'Toole Martin G, Kreso Majda, Kozlowski Pawel M, Mashuta Mark S, Grapperhaus Craig A
Department of Chemistry, University of Louisville, Louisville, KY 40292, USA.
J Biol Inorg Chem. 2008 Nov;13(8):1219-30. doi: 10.1007/s00775-008-0405-4. Epub 2008 Jul 17.
The oxygen sensitivity of two related iron(III) dithiolate complexes of the ligand [4,7-bis-(2'-methyl-2'-mercatopropyl)-1-thia-4,7-diazacyclononane], (bmmp-TASN)FeCN (1) and (bmmp-TASN)FeCl (2), has been examined. Oxygen exposure of the low-spin complex 1 yields the disulfonate complex (bmmp-O6-TASN)FeCN (3) as an olive-green solid with characteristic peaks in the IR spectrum at 1262, 1221, 1111, 1021, 947, 800, and 477 cm(-1). The corresponding nickel dithiolate, (bmmp-TASN)Ni (4), yields the related disulfonato derivative, (bmmp-O6-TASN)Ni (5) upon addition of H2O2 (IR bands at 1258, 1143, 1106, 1012, 800, and 694 cm(-1). Oxygen exposure of the high-spin complex 2 results in disulfide formation and decomplexation of the metal with subsequent iron-oxo cluster formation. Complexes 1 and 2 were examined using density functional theory calculations. A natural bond order/natural localized molecular orbital covalency analysis reveals that the low-spin complex 1 contains Fe-Sthiolate bonds with calculated covalencies of 75 and 86%, while the high-spin complex 2 contains Fe-Sthiolate bonds with calculated covalencies of 11 and 40%. The results indicate the degree of covalency of the Fe-S bonds plays a major role in determining the reaction pathway associated with oxygen exposure of iron thiolates. The X-ray structures of 1, 4, and 5 are reported.
对配体[4,7-双-(2'-甲基-2'-巯基丙基)-1-硫杂-4,7-二氮杂环壬烷]的两种相关二硫醇铁(III)配合物(bmmp-TASN)FeCN (1)和(bmmp-TASN)FeCl (2)的氧敏感性进行了研究。低自旋配合物1暴露于氧气中会生成二磺酸根配合物(bmmp-O6-TASN)FeCN (3)，呈橄榄绿色固体，红外光谱在1262、1221、1111、1021、947、800和477 cm⁻¹处有特征峰。相应的二硫醇镍(bmmp-TASN)Ni (4)在加入H₂O₂后会生成相关的二磺酸根衍生物(bmmp-O6-TASN)Ni (5)（红外谱带在1258、1143、1106、1012、800和694 cm⁻¹处）。高自旋配合物2暴露于氧气中会导致二硫键形成以及金属解络合，随后形成铁氧簇。使用密度泛函理论计算对配合物1和2进行了研究。自然键序/自然定域分子轨道共价性分析表明，低自旋配合物1含有计算共价性分别为75%和86%的Fe - 硫醇盐键，而高自旋配合物2含有计算共价性分别为11%和40%的Fe - 硫醇盐键。结果表明，Fe - S键的共价程度在决定与硫醇铁暴露于氧气相关的反应途径中起主要作用。报道了1、4和5的X射线结构。
