Fluxional and Rigid (Trimethylphosphane)cobalt Complexes Containing Chelating (2‐Diphenylphosphanyl)anilido Ligands

Abstract 2‐(Diphenylphosphanyl)anilines (P ∧ NHR) eliminate methane upon reaction with [CoMe(PMe 3 ) 4 ] forming the complexes [Co(η 2 ‐P ∧ NR)(PMe 3 ) 3 ] ( 1 : R = H; 2 : R = Me) and [Co(η 2 ‐P ∧ NR)(PMe 3 ) 2 ] ( 3 : R = Me). Reaction with HCl gives [CoCl(η 1 ‐P ∧ NHR)(PMe 3 ) 2 ] ( 4 : R = H; 5 : R = Me) and reaction with CO or olefin gives [Co(η 2 ‐P ∧ NR)(CO)(PMe 3 ) 2 ] ( 6 : R = H; 7 : R = Me) and [Co(η 2 ‐P ∧ NR)(olefin)(PMe 3 ) 2 ] ( 8 : R = H, olefin = C 2 H 4 ; 9 : R = Me, olefin = C 2 H 4 ; 10 : R = Me, olefin = C 3 H 6 ), respectively. No catalytic transformation of the olefins was observed. Oxidation by iodomethane yields a cobalt( II ) compound [CoI(η 2 ‐P ∧ NR)(PMe 3 ) 2 ] ( 11 : R = Me). By treating 2‐(diphenylphosphanyl)aniline with [CoMe 2 (PMe 3 ) 3 ] a methylcobalt( II ) complex [CoMe(η 2 ‐P ∧ NR)(PMe 3 ) 2 ] ( 12 : R = H) is obtained, while an excess of the aniline produces [Co(η 2 ‐P ∧ NR) 2 ] ( 13 : R = H; 14 : R = Me) or [Co(η 2 ‐P ∧ NR) 2 (PMe 3 )] ( 15 : R = H; 16 : R = Me). The methylcobalt( III ) complexes mer ‐ trans ‐[CoIMe 2 (η 2 ‐P ∧ NR)(PMe 3 ) 2 ] were obtained from LiP ∧ NR and [CoClMe 2 (PMe 3 ) 3 ]. Dynamic 31 P NMR spectra and the structures of complexes 3 , 6 , 12 , and 13 are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)