title: Synthesis of a Silyl Cobalt Hydride and Its Catalytic Performance in Kumada Coupling Reactions.
abstract: Four silyl [P,Si]-chelate cobalt complexes (2-5) have been synthesized through the chelate-assisted Si-H activation of bidentate preligand ortho-HSi(Me)2(PPh2)C6H4(1) with CoMe(PMe3)4and CoCl(PMe3)3. The silyl CoIcomplex, Co(PMe3)3(1-Si(Me)2-2-(PPh2)C6H4) (2), was synthesized by Si-H activation of 1 with CoMe(PMe3)4or by combining complex 5 with MeLi and PMe3. Complex 2 was treated with CH3I or EtBr, generating the silyl CoIIproducts CoI(PMe3)2(1-Si(Me)2-2-(PPh2)C6H4) (3) and CoBr(PMe3)2(1-Si(Me)2-2-(PPh2)C6H4) (4). The silyl CoIIIhydride, CoHCl(PMe3)2(1-Si(Me)2-2-(PPh2)C6H4) (5), was obtained by the reaction of complex 1 with CoCl(PMe3)3. The catalytic performance of complex 5 was explored for Kumada coupling reactions, showing good to excellent catalytic efficiency with 2 mol % catalyst loading for the reactions of aryl chlorides or aryl bromides with Grignard reagents. It is noteworthy that the synthesis of 5 as a chelate complex is easier than that of previously reported [PSiP]-pincer cobalt hydride. With similar catalytic efficiency for Kumada reactions, the catalyst loading (2 %) of 5 was lower than that (5 %) of [PSiP]-pincer cobalt hydride.
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199, Jinan, People's Republic of China.
authors.forename: Shilu
authors.initials: S
authors.lastname: Xu
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199, Jinan, People's Republic of China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199, Jinan, People's Republic of China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199, Jinan, People's Republic of China.
authors.forename: Benjing
authors.initials: B
authors.lastname: Xue
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Special Functional Aggregated Materials, Ministry of Education, Shandong University, Shanda Nanlu 27, 250199, Jinan, People's Republic of China.
authors.forename: Hongjian
authors.initials: H
authors.lastname: Sun
authors.affiliation: Institut für Nanotechnologie (INT) und Karlsruher Nano-Micro-Facility (KNMF), Karlsruher Institut für Technologie (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Fuhr
authors.affiliation: Institut für Nanotechnologie (INT) und Karlsruher Nano-Micro-Facility (KNMF), Karlsruher Institut für Technologie (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Fenske
keywords: C-C coupling; Kumada coupling; Si-H activation; cobalt; silyl cobalt complexes