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Abstract The dehydration reactions from primary amides to nitriles were catalyzed by the [CNC]-pincer hydrido cobalt(III) complexes [(ortho -F 4 C 6 CH N C 10 H 6)Co(III)(H)(PMe 3) 2 ] (1), [(2,5-F 2 C 6 H 2 CH N C 10 H 6)Co(III)(H)(PMe 3) 2 ] (2) and [(2,4,5-F 3 C 6 H CH N C 10 H 6)Co(III)(H)(PMe 3) 2 ] (3) as catalysts with (EtO) 3 SiH as an efficient reducing agent. These hydrido cobalt(III) complexes as catalysts are suitable for many substrates and have good functional group tolerance. Among the three cobalt hydrides, complex 2 is the best catalyst. This is the first hydrido cobalt complex-catalyzed dehydration of primary amides to nitriles. Graphical abstract Unlabelled Image Highlights • CNC-pincer cobalt hydride could catalyze dehydration of amides to nitriles. • The catalytic system has tolerance to many functional groups. • This is the first cobalt hydride-catalyzed dehydration of amides to nitriles. [ABSTRACT FROM AUTHOR]

Three novel selenophenolato hydrido iron(II) complexes [ cis -(H)(SeAr)Fe(PMe 3 ) 4 ] ( 4–6 ) (Ar=C 6 H 5 ( 4 ), p -MeOC 6 H 4 ( 5 ) and o -MeC 6 H 4 ( 6 )) were prepared through the reaction of Fe(PMe 3 ) 4 with selenophenols ArSeH ( 1–3 ) via Se–H activation. The iron hydrido complexes 4 , 5 and 6 could catalyze the hydrosilylation of aldehydes and ketones. Among them complex 5 is the best catalyst for this process. Furthermore, α,β-unsaturated alcohols could be obtained from the selective reduction reactions of the corresponding α,β-unsaturated carbonyls catalyzed by hydrido iron(II) complex 5 . This catalytic system has good tolerance for some common groups but it is easy to reduce the nitro group to an amino group. The experiments indicate that the chemoselectivity for this catalytic system is CHO> NO 2 > C( O)CH 3 . The crystal structure of 6 was determined by X-ray diffraction. [ABSTRACT FROM AUTHOR]

The hydrido silyl iron complex (o-Ph2PC6H4SiMe2)Fe(PMe3)3H (2) was obtained via the activation of the Si–H bond of the bidentate silyl ligand o-Ph2P(C6H4)SiMe2H (1) by Fe(PMe3)4. 2 showed good to excellent catalytic activity in both the reduction of aldehydes/ketones and the dehydration of benzamide. In addition, with complex 2 as a catalyst, α,β-unsaturated carbonyls could be selectively reduced to the corresponding α,β-unsaturated alcohols. The mechanisms of the formation of 2 and the catalytic dehydration process are proposed and partly experimentally verified. [ABSTRACT FROM AUTHOR]

Two novel cobalt Schiff base complexes 3 and 4, ((2-PPh2)C6H4)C=N(C10H7)Co(PMe3)2 (3) and ((2-PPh2)C6H4)CH=N(C6H5)Co(PMe3)2 (4) with η2(C–H) coordination, were synthesized by the reactions of Schiff base preligands ((2-PPh2)C6H4)CH=N(C10H7) (1) and ((2-PPh2)C6H4)CH=N(C6H5) (2) with CoMe(PMe3)4via sp2 C–H bond activation. Under similar reaction conditions, the reactions of Co(PMe3)4 with 1 and 2 gave rise to the simple π-(C=N)-coordinated cobalt(0) complexes ((2-PPh2)C6H4)CH=N(C10H7)Co(PMe3)2 (5) and ((2-PPh2)C6H4)CH=N(C6H5)Co(PMe3)2 (6). Complex ((2-PPh2)C6H4)C=N(C10H6)CoI(PMe3)2 (7) was obtained through the reaction of 3 with iodomethane via the activation of the second C–H bond in 1. The substitution reaction of complex 3 with carbon monoxide afforded the dicarbonyl cobalt(i) complex ((2-PPh2)C6H4)C=N(C10H7)Co(CO)2(PMe3) (8). The molecular structures of 4, 5, 7 and 8 were determined by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

A catalytic system of regioselective synthesis of allyl sulfides via hydrothiolation of terminal arylallenes with arylthiols has been developed using nickel(0) complex Ni (PMe3)4 as a catalyst. In most cases the excellent to moderate yields were obtained under mild conditions. A catalytic mechanism was suggested and partially‐experimentally verified. To the best of our knowledge, this is the first example of regioselective addition of thiophenols to terminal arylallenes catalyzed by nickel(0) complex. It was noteworthy that this catalytic system was only applicable to thiophenol compounds with terminal arylallenes. [ABSTRACT FROM AUTHOR]

A catalytic system of regioselective synthesis of allyl sulfides via hydrothiolation of terminal arylallenes with arylthiols has been developed using nickel(0) complex Ni (PMe3)4 as a catalyst. In most cases the excellent to moderate yields were obtained under mild conditions. A catalytic mechanism was suggested and partially‐experimentally verified. To the best of our knowledge, this is the first example of regioselective addition of thiophenols to terminal arylallenes catalyzed by nickel(0) complex. It was noteworthy that this catalytic system was only applicable to thiophenol compounds with terminal arylallenes. [ABSTRACT FROM AUTHOR]