Synthesis and Reactivity of Iron Complexes with a New Pyrazine-Based Pincer Ligand, and Application in Catalytic Low-Pressure Hydrogenation of Carbon Dioxide
作者:Orestes Rivada-Wheelaghan、Alexander Dauth、Gregory Leitus、Yael Diskin-Posner、David Milstein
DOI:10.1021/acs.inorgchem.5b00366
日期:2015.5.4
Bu4NCl forms [Fe(H)(Cl)(CO)(tBu-PNzP)] 5. Complex 5, under basic conditions, catalyzes the hydrogenation of CO2 to formate salts at low H2 pressure. Treatment of complex 5 with a base leads to aggregates, presumably of dearomatized species B, stabilized by bridging to another metal center by coordination of the nitrogen at the backbone of the pyrazine pincer ligand. Upon dissolution of compound B in
合成了一种基于吡嗪骨架 (PNzP) 的新型钳状配体,(2,6-双(二(叔丁基)膦甲基)吡嗪),tBu-PNzP。它与 FeBr 2反应生成[Fe(Br) 2 (tBu-PNzP)], 1。在 MeCN/MeOH中用 NaBH 4处理1得到氢化物复合物 [Fe(H)(MeCN) 2 (tBu-PNzP)][X] (X = Br, BH 4 ), 2·X。反离子交换和暴露于 CO 气氛产生复杂的顺- [Fe(H)(CO)(MeCN)(tBu-PNzP)][BPh 4 ] 4·BPh 4,在加入 Bu 4 NCl 后形成 [Fe(H) )(Cl)(CO)(tBu-PNzP)]5 . 在碱性条件下,配合物5在低 H 2压力下催化 CO 2氢化成甲酸盐。用碱处理配合物5导致聚集体,推测是脱芳构化物质B,通过吡嗪钳配体骨架上的氮的配位桥接到另一个金属中心而稳定。在将化合物B溶解在 EtOH 中后,形