报道了一种将氢醌环化为Fe 2 S 2(CO)6部分的新合成方法。哌啶催化Fe 2(μ-SH)2(CO)6之间的多步反应和醌以26-76%的收率提供桥接的加合物。氢醌加合物经历可逆的两电子还原。在乙酸的存在下,这些加合物催化生成的氢的电势比初始可逆还原的电势更负。光谱研究表明在酚羟基和相邻的硫原子之间存在分子内氢键。与电化学研究和光谱数据高度吻合的计算表明,在还原形式的催化剂中氢键是最重要的。该氢键降低了催化的还原电位,但也降低了碱性,并因此降低了催化剂的反应性。
DOI:
10.1021/om100396j
作为产物:
描述:
bis(μ-mercapto)bis(tricarbonyliron) 、 1,4-蒽醌 在
catalyst: piperidine 作用下,
以
not given 为溶剂,
以57%的产率得到Fe2(CO)6(μ-S2C14H6O2)
报道了一种将氢醌环化为Fe 2 S 2(CO)6部分的新合成方法。哌啶催化Fe 2(μ-SH)2(CO)6之间的多步反应和醌以26-76%的收率提供桥接的加合物。氢醌加合物经历可逆的两电子还原。在乙酸的存在下,这些加合物催化生成的氢的电势比初始可逆还原的电势更负。光谱研究表明在酚羟基和相邻的硫原子之间存在分子内氢键。与电化学研究和光谱数据高度吻合的计算表明,在还原形式的催化剂中氢键是最重要的。该氢键降低了催化的还原电位,但也降低了碱性,并因此降低了催化剂的反应性。
Redox Chemistry of Noninnocent Quinones Annulated to 2Fe2S Cores
作者:Gabriel B. Hall、Jinzhu Chen、Charles A. Mebi、Noriko Okumura、Matthew T. Swenson、Stephanie E. Ossowski、Uzma I. Zakai、Gary S. Nichol、Dennis L. Lichtenberger、Dennis H. Evans、Richard S. Glass
DOI:10.1021/om400913p
日期:2013.11.11
Noninnocent ligands that are electronically coupled to active catalytic sites can influence the redox behavior of the catalysts. A series of (mu-dithiolato)Fe-2(CO)6 complexes, in which the sulfur atoms of the mu-dithiolato ligand are bridged by 5-substituted (Me, OMe, Cl, t-Bu)-1,4-benzoquinones, 1,4-naphthoquinone, or 1,4-anthraquinone, have been synthesized and characterized. In addition, the bisphosphine complex derived from the 1,4-naphthoquinone-bridged complex has also been prepared and characterized. Cyclic voltammetry of these complexes shows two reversible one-electron reductions at potentials 0.2 to 0.5 V less negative than their corresponding parent quinones. In the presence of acetic acid two-electron reductions of the complexes result in conversion of the quinones to hydroquinone moieties. EPR spectroscopic and computational studies of the one-electron-reduced complexes show electron delocalization from the semiquinones to the 2Fe2S moieties, thereby revealing the "noninnocent" behavior of these ligands with these catalysts.