Preparation of hydrido [CNC]-pincer cobalt complexes via selective C–H/C–F bond activation and their catalytic performances. (17th August 2018)

• Record Type: Journal Article
• Authors: Yang, Fei; Wang, Yangyang; Lu, Faguan; Xie, Shangqing; Qi, Xinghao; Sun, Hongjian; Li, Xiaoyan; Fuhr, Olaf; Fenske, Dieter
• Is Part Of: New journal of chemistry. Volume 42:Number 19(2018)
• Page Start: 15578
• Page End: 15586
• Publication Date: 2018-08-17
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c8nj02979b
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : [CNC]-pincer Co hydrides were synthesized via selective C–H/C–F activation and catalyzed hydrosilylation of carbonyl compounds. Abstract : Polyfluorinated aryl imines 2, 4, 5-R1, R2, R3 -C6 H2 -HCN-1-C10 H7 (R1 = F, R2 = F, R3 = H (1 ); R1 = F, R2 = H, R3 = F (2 ) and R1 = F, R2 = F, R3 = F (3 )) and F5 C6 -HCN-1-C10 H7 (7 ) reacted with CoMe(PMe3 )4 to give rise to hydrido [CNC]-pincer cobalt(iii ) complexes (2, 4, 5-R1, R2, R3 -C6 H-HCN-1-C10 H6 )Co(H)(PMe3 )2 (R1 = F, R2 = F, R3 = H (4 ); R1 = F, R2 = H, R3 = F (5 ); R1 = F, R2 = F, R3 = F (6 )) and (F4 C6 -HCN-1-C10 H6 )Co(H)(PMe3 )2 (8 ) via selective C–F/C–H bond activation. Penta-coordinate dicarbonyl cobalt(i ) complexes (2, 4, 5-R1, R2, R3 -C6 H-HCN-1-C10 H7 )Co(CO)2 (PMe3 ) (R1 = F, R2 = H, R3 = F (9 ); R1 = F, R2 = F, R3 = F (10 )) were obtained from reactions of hexa-coordinate cobalt(iii ) complexes5 and6 with carbon monoxide through reductive elimination. Cobalt(iii ) halides (2, 4, 5-R1, R2, R3 -C6 H-HCN-1-C10 H6 )Co(i )(PMe3 )2 (R1 = F, R2 = F, R3 = H (11 ); R1 = F, R2 = H, R3 = F (12 ); R1 = F, R2 = F, R3 = F (13 )) and (2, 4, 5-R1, R2, R3 -C6 H-HCN-1-C10 H6 )Co(Br)(PMe3 )2 (R1 = F, R2 = F, R3 = H (14 ); R1 = F, R2 = H, R3 = F (15 ); R1 = F, R2 = F, R3 = F (16 )) were prepared by the interaction between hydrido cobalt(iii ) complexes4–6 and MeI or EtBr. The molecular configurations of complexes4, 8, and11 were determined by single crystal X-ray diffraction. We then confirmed that the four hydrido cobalt(iii ) complexes4–6 and8 could be used as catalysts for reduction of aldehydes and ketones. Complex8 is the best catalyst among the four complexes and can selectively catalyze the carbonyl groups of α, β-unsaturated aldehydes and ketones.