Formation of the Cationic [(2‐Aminoethenyl)carbine]iron Complexes by Treatment of (2‐Methoxyethenyl)carbene Complexes with Primary Amines:Synthesis and Characterisation

Cationic (2‐methoxyethenyl)methoxycarbene iron complexes 2 , [Cp(CO) 2 Fe(C(OMe)CHCR(OMe)) + ][PF 6 − ], are obtained by the addition of methanol to the corresponding (alkynyl)‐methoxycarbene complexes 1 , [Cp(CO) 2 Fe(C(OMe)CCR) + ][PF 6 − ]. Primary amines, H 2 NR', react with these 1,3‐dimethoxy‐substituted (alkenyl)carbene complexes, 2 , through an addition/elimination process to yield cationic (2‐aminoethenyl)methoxycarbene iron complexes, 3 , [Cp(CO) 2 Fe(C(OMe)CHCR(NHR')) + ][PF 6 − ] in an isolated yield of 71–90%. The complexes 3a–c were characterized by X‐ray structural analyses. Thus, previously isolated products, from the reaction, of the (alkynyl)methoxycarbene complexes 1a and 1c , with aniline at room temperature, are assigned to the structures 3c and 3e . The spectroscopic and structural data obtained are discussed.