Synthese und Reaktionen der Metall‐Base [(C 5 Me 4 H)Co(PMe 3 ) 2 ]

Synthesis and Reactions of the Metal Base [(C 5 Me 4 H)Co(PMe 3 ) 2 ] The (tetramethylcyclopentadienyl)cobalt complex [(C 5 Me 4 H)Co(PMe 3 ) 2 ] ( 1 ), which is prepared from [CoCl(PMe 3 ) 3 ] and LiC 5 Me 4 H in 75% yield, behaves like a Lewis base and reacts with NH 4 PF 6 , CH 3 I, or CF 3 SO 3 CH 3 by oxidative addition to give the cations [(C 5 Me 4 H)CoX(PMe 3 ) 2 ] + (X = H, I, CH 3; 2–4 ) isolated as PF 6 salts. From 3 (X = I) and excess LiCH 3 the dimethylcobalt(III) compound [(C 5 Me 4 H)Co(CH 3 ) 2 (PMe 3 )] ( 5 ) is obtained. Treatment of the corresponding trifluoroacetato derivative [(C 5 Me 4 H)Co(PMe 3 )(OCOCF 3 ) 2 ] ( 6 ) with PMe 3 , P(OMe) 3 , and 1,2‐C 6 H 4 (PPh 2 ) 2 leads, in the presence of NH 4 PF 6 , to the formation of the cationic complexes 7–9 . The displacement of the two PMe 3 ligands in 1 by (Ph 2 P) 2 NMe gives the rather unstable chelate compound {(C 5 Me 4 H)Co[(Ph 2 P) 2 NMe]} ( 10 ), which on treatment with NH 4 PF 6 is transformed into the stable complex {(C 5 Me 4 H)CoH[(Ph 2 P) 2 NMe]}PF 6 ( 11 ). The structure of 11 has been determined by X‐ray diffraction methods.