260975-57-3Relevant academic research and scientific papers
Oxidation-reduction exchange of 2-acylenolato and trimethylphosphane ligands between d6 and d8 complexes of nickel and cobalt
Klein, Hans-Friedrich,Li, Xiaoyan,Sun, Hongjian,Beck, Robert,Fl?rke, Ulrich,Haupt, Hans-Jürgen
, p. 63 - 69 (2008/10/08)
A series of five (C:O)-dianionic 1-acyl-2-enolato ligands C(O)-C=C-O in a transmetallation reaction between 18-electron metal-d6 complexes mer-trans-NiMe(X)[C(O)-C=C-O](PMe3)2 [C=C=C6H4, X = I (1); C=C=3-CMe3-5-Me-C6H2, X = I (2); C=C=5,6-benzo-C6H2, X = I (3); C=C=3,4-benzo-cyclohexene, X = Br (4); C=C=1,2-diphenylethene, X = I (5)] and the 18-electron metal-d8 compound CoMe(PMe3)4 (1:2), undergo a reductive coupling of acyl and methylnickel functions involving the C(O)-C=C-O ligands. Subsequent migration of methyl groups between cobalt intermediates generates three products: mer-trans-CoMe2[MeC(O)-C=C-O](PMe3)2 (6-10), Ni(PMe3)4, and CoX(PMe3)3. The X-ray crystal structure of compound 7 has been determined. The methyl ligands are found in positions opposite to the O-donor functions. Upon replacing the aromatic rings in salicylaldehyde derivatives C(O)-C=C-O by more flexible cyclohexene rings or acyclic systems the reduction of Ni(IV) complexes follows a different course. (C) 2000 Elsevier Science S.A.
