氟化钴(II)络合物,[L t Bu Co(μ-F)] 2 [L t Bu = 2,2,6,6-四甲基-3,5-双(2,6-二异丙基苯基亚氨基)庚烷4基],被从L-合成吨卜联合使用我3经由的SnF键的均裂的SnF。L t Bu Co还执行了氟化芳烃的整体双核氧化加成反应,得到摩尔比为1:2的[L t Bu Co(μ-F)] 2和相应氟苯底物的钴(II)芳基络合物。C–F活化反应对钴和氟苯的浓度都具有一级速率依赖性。该速率由meta增加-氟化物取代基,以及被邻-氟化物取代物减慢的速度,分别表明电子和位阻对过渡态的影响。这些数据与一个机构开头限速氧化加成的芳基氟化物,以钴最一致的(I),随后快速还原钴(III)的氟化芳基中间体由L的第二分子吨卜公司[L t Bu Co(μ-F)] 2也与Et 3 SiH反应生成氢化物配合物[L t Bu Co(μ-H)] 2。与较早的报道相反,该氢化物配合物对烯烃和N
氟化钴(II)络合物,[L t Bu Co(μ-F)] 2 [L t Bu = 2,2,6,6-四甲基-3,5-双(2,6-二异丙基苯基亚氨基)庚烷4基],被从L-合成吨卜联合使用我3经由的SnF键的均裂的SnF。L t Bu Co还执行了氟化芳烃的整体双核氧化加成反应,得到摩尔比为1:2的[L t Bu Co(μ-F)] 2和相应氟苯底物的钴(II)芳基络合物。C–F活化反应对钴和氟苯的浓度都具有一级速率依赖性。该速率由meta增加-氟化物取代基,以及被邻-氟化物取代物减慢的速度,分别表明电子和位阻对过渡态的影响。这些数据与一个机构开头限速氧化加成的芳基氟化物,以钴最一致的(I),随后快速还原钴(III)的氟化芳基中间体由L的第二分子吨卜公司[L t Bu Co(μ-F)] 2也与Et 3 SiH反应生成氢化物配合物[L t Bu Co(μ-H)] 2。与较早的报道相反,该氢化物配合物对烯烃和N
A Masked Two-Coordinate Cobalt(I) Complex That Activates C–F Bonds
作者:Thomas R. Dugan、Xianru Sun、Elena V. Rybak-Akimova、Olayinka Olatunji-Ojo、Thomas R. Cundari、Patrick L. Holland
DOI:10.1021/ja2052914
日期:2011.8.17
We report the isolation, characterization, and reactions of the unsaturated complex (LCo)-Co-tBu (L-tBu = bulky beta-diketiminate ligand). The unusual slipped kappa N,eta(6)-arene binding mode in (LCo)-Co-tBu interconverts rapidly and reversibly with the traditional kappa N-2,N' ligation mode upon binding of Lewis bases, making it a "masked" two-coordinate complex. The mechanism of this isomerization is demonstrated using kinetic studies. (LCo)-Co-tBu is a stable yet reactive synthon for low-coordinate cobalt(I) complexes and is capable of cleaving the C-F bond in fluorobenzene.