Large Equatorial Ligand Effects on C-H Bond Activation by Nonheme Iron(IV)-oxo Complexes

• 作 者: XiaoliSun;CaiyunGeng;XuriHuang;JilaiLi;
• 机 构: State Key Laboratory of Theoretical and Computational Chemistry,Institute of Theoretical Chemistry,J
• 出 处: 第十二届全国量子化学会议
• 发表日期: 2014年期

　　In this article we present density functional theory(DFT)calculations on the iron(IV)-oxo catalyzed methane C-H activation reactions for complexes in which the FeIV=O core is surrounded by five negatively charged ligands.We found that it follows a hybrid pathway that mixes features of the classical σ and π pathways in quintet surfaces.These calculations show that,the Fe-O-H arrangement in this hybrid pathway is bent,in sharp contrast to the collinear character as observed for the classical quintet σ pathways before[1-3].The calculations have also shown that it is the equatorial ligands that play key roles in tuning the reactivity of FeIV=O complexes.The strong π-donating equatorial ligands employed in the current study cause a weak π(FeO)bond and thereby shift the electronic accepting orbitals(EAO)from the vertically orientated O pz orbital to the horizontally orientated O px.In addition,all the equatorial ligands are small in size and would therefore be expected have small steric effects upon substrate horizontal approaching.Therefore,for the small and strong π-donating equatorial ligands,the collinear Fe-O-H arrangement is not the best choice for the quintet reactivity.This study adds new element to iron(IV)-oxo catalyzed C-H bond activation reactions.