C-Cl bond activation of ortho-chlorinated benzamides by nickel and cobalt compounds supported with phosphine ligands.
The C-Cl bonds of ortho-chlorinated benzamides Cl-ortho-C(6)H(4)C(=O)NHR (R = Me (1), nBu (2), Ph (3), (4-Me)Ph (4) and (4-Cl)Ph (5)) were successfully activated by tetrakis(trimethylphosphine)nickel(0) and tetrakis(trimethylphosphine)cobalt(0). The four-coordinate nickel(II) chloride complexes trans-[(C(6)H(4)C([double bond, length as m-dash]O)NHR)Ni(PMe(3))(2)Cl] (R = Me (6), nBu (7), Ph (8) and (4-Me)Ph (9)) as C-Cl bond activation products were obtained without coordination of the amide groups. In the case of 2, the ionic penta-coordinate cobalt(II) chloride [(C(6)H(4)C(=O)NHnBu)Co(PMe(3))(3)]Cl (10) with the [C(phenyl), O(amide)]-chelate coordination as the C-Cl bond activation product was isolated. Under similar reaction conditions, for the benzamides 3-5, hexa-coordinate bis-chelate cobalt(III) complexes (C(6)H(4)C(=O)NHR)Co(Cl-ortho-C(6)H(4)C(=O)NR)(PMe(3))(2) (11-13) were obtained via the reaction with [Co(PMe(3))(4)]. Complexes 11-13 have both a five-membered [C,N]-coordinate chelate ring and a four-membered [N,O]-coordinate chelate ring with two trimethyphosphine ligands in the axial positions. Phosphonium salts [Me(3)P(+)-ortho-C(6)H(4)C(=O)NHR]Cl(-) (R = Ph (14) and (4-Me)Ph (15)) were isolated by reaction of complexes 8 and 9 as a starting material under 1 bar of CO at room temperature. The crystal and molecular structures of complexes 6, 7 and 9-12 were determined by single-crystal X-ray diffraction.
School of Chemistry and Chemical Engineering, Shandong University, Shanda Nanlu 27, 250100, Jinan, People's Republic of China.
Junye
J
Li
Chenggen
C
Wang
Xiaoyan
X
Li
Hongjian
H
Sun
D001549:Benzamides / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D054879:Halogenation; D008024:Ligands; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010720:Phosphines / Q000737:chemistry; D014961:X-Ray Diffraction
D001549:Benzamides; D056831:Coordination Complexes; D008024:Ligands; D009942:Organometallic Compounds; D010720:Phosphines; D003035:Cobalt; D009532:Nickel