Department of Chemistry and Biochemistry, Auburn University , Auburn, Alabama 36849, United States.
Inorg Chem. 2013 Dec 2;52(23):13546-54. doi: 10.1021/ic402501k. Epub 2013 Nov 19.
The compound N,N'-dineopentyl-N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine (dnbpn) and its ferrous complex [Fe(dnbpn)(OTf)2] were synthesized. The Fe(II) complex was used to catalyze the oxidation of hydrocarbons by H2O2 and O2. Although the catalyzed alkane oxidation by H2O2 displays a higher preference for secondary over tertiary carbons than those associated with most previously reported nonheme iron catalysts, the catalytic activity is markedly inferior. In addition to directing the catalyzed oxidation toward the less sterically congested C-H bonds of the substrates, the neopentyl groups destabilize the metal-based oxidants generated from H2O2 and the Fe(II) complex. The presence of benzylic substrates with weak C-H bonds stabilizes an intermediate which we have tentatively assigned as a high-spin ferric hydroperoxide species. The oxidant generated from O2 reacts with allylic and benzylic C-H bonds in the absence of a sacrificial reductant; less substrate dehydrogenation is observed than with related previously described systems that use O2 as a terminal oxidant.
合成了化合物 N,N'-二正戊基-N,N'-双(2-吡啶甲基)-1,2-乙二胺（dnbpn）及其亚铁配合物[Fe(dnbpn)(OTf)2]。该亚铁配合物用于催化 H2O2 和 O2 氧化烃类。尽管与大多数先前报道的非血红素铁催化剂相比，Fe(II)配合物催化的 H2O2 氧化烷烃对仲碳的选择性高于叔碳，但催化活性明显较低。除了使催化氧化定向于底物中空间位阻较小的 C-H 键外，新戊基基团还使 H2O2 和 Fe(II)配合物生成的基于金属的氧化剂不稳定。具有弱 C-H 键的苄基底物的存在稳定了我们暂定为高自旋铁过氧物种的中间产物。由 O2 生成的氧化剂在没有牺牲还原剂的情况下与烯丙基和苄基 C-H 键反应；与使用 O2 作为末端氧化剂的相关先前描述的体系相比，观察到的底物脱氢较少。
