标题：Synthesis and Reactivity of N-Heterocyclic PSiP Pincer Iron and Cobalt Complexes and Catalytic Application of Cobalt Hydride in Kumada Coupling Reactions
作者：Xiong, Zichang; Li, Xiaoyan; Zhang, Shumiao; Shi, Yaomin; Sun, Hongjian
作者机构：[Xiong, Zichang; Li, Xiaoyan; Zhang, Shumiao; Shi, Yaomin; Sun, Hongjian] Shandong Univ, Sch Chem & Chem Engn, Key Lab Special Funct Aggregated Mat, M 更多
通讯作者地址：[Sun, HJ]Shandong Univ, Sch Chem & Chem Engn, Key Lab Special Funct Aggregated Mat, Minist Educ, Shanda Nanlu 27, Jinan 250199, Peoples R China.
摘要：The new N-heterocyclic sigma-silyl pincer ligand HSiMe-(NCH2PPh2)(2)C6H4 (1) was designed. A series of tridentate silyl pincer Fe and Co complexes were prepared. Most of them were formed by chelate-assisted Si-H activation. The typical iron hydrido complex FeH(PMe3)(2)(SiMe(NCH2PPh2)(2)C6H4) (2) was obtained by Si-H activation of compound 1 with Fe(PMe3)(4). The combination of compound 1 with CoMe(PMe3)(4) afforded the Co(I) complex Co(PMe3)(2)(SiMe(NCH2PPh2)(2)C6H4) (3). The Co(III) complex CoHCl(PMe3)(SiMe(NCH2PPh2)(2)C6H4) (5) was generated by the reaction of complex 1 with CoCl(PMe3)(3) or the combination of complex 3 with HCl. However, when complex 3 was treated with MeI, the Co(II) complex CoI(PMe3)(SiMe(NCH2PPh2)(2)C6H4) (4), rather than the Co(III) complex, was isolated. The catalytic performance of complex 5 for Kumada coupling reactions was explored. With a catalyst loading of 5 mol %, complex 5 displayed efficient catalytic activity for Kumada cross-coupling reactions of aryl chlorides and aryl bromides with Grignard reagents. This catalytic reaction mechanism is proposed and partially experimentally verified.