Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario, Canada , M5S 3H6.
J Am Chem Soc. 2013 Oct 30;135(43):16175-83. doi: 10.1021/ja4073832. Epub 2013 Oct 17.
The 4,5-diazafluorenide ligand (L(-)) serves as an actor ligand in the formal insertion of CO2 into a C-H bond remote from the metal center. With the Ru(II) complex of L(-) as the starting point, Rh(III), Rh(I), and Cu(I) were used as spectator metal centers to tune the reactivity of the actor ligand toward CO2. In the case of Rh(III)-diazafluorenide a room temperature reversible activation of CO2 was observed, similar to the isoelectronic Ru(II) analogue. In the case of Rh(I)- and Cu(I)-diazafluorenide CO2 is trapped by the formation of dinuclear carboxylate complexes and diazafluorene (LH). The spectator metal center could even be replaced entirely with an organic group allowing for the first metal-free reversible tandem CO2 and C-H activation.
4,5-二氮菲配体（L(-)）作为一个形式插入 CO2 进入远离金属中心的 C-H 键的作用配体。以 L(-)的 Ru(II)配合物为起点，使用 Rh(III)、Rh(I)和 Cu(I)作为旁观金属中心来调节作用配体对 CO2 的反应性。在 Rh(III)-二氮菲的情况下，观察到 CO2 的室温可逆活化，类似于等电子的 Ru(II)类似物。在 Rh(I)-和 Cu(I)-二氮菲的情况下，CO2 通过形成双核羧酸盐配合物和二氮菲（LH）而被捕获。旁观金属中心甚至可以完全被一个有机基团取代，从而实现首例无金属的可逆串联 CO2 和 C-H 活化。
