Synthesis and characterization of amine complexes of the cyclopentadienyliron dicarbonyl complex cation, [Cp(CO)2Fe

Abstract

The organometallic Lewis acid, [CpFe(CO)2]+BF4- (Cp=η5-C5H5) reacts with excess dry diethyl ether at low temperatures to form the labile complex [CpFe(CO)2(Et2O)]+[BF4]− (1) which is stable at low temperatures and has been fully characterized. Complex 1 in turn reacts with 1-aminoalkanes and α,ω-diaminoalkanes to form new complexes of the type [CpFe(CO)2NH2(CH2)nCH3]BF4 (n=2–6) (2) and [{CpFe(CO)2}2μ-(NH2(CH2)nNH2)](BF4)2 (n=2–4) (3), respectively. These complexes have been fully characterized and the mass spectral patterns of complexes 2 are reported. The structures of compounds 2a (n=2) and 2b (n=3) have been confirmed by single crystal X-ray crystallography. The single crystal X-ray diffraction data show that complex 2a, [CpFe(CO)2NH2(CH2)2CH3]BF4, crystallizes in a triclinic P1¯ space group while 2b, [CpFe(CO)2NH2(CH2)3CH3]BF4, crystallizes in an orthorhombic Pca21 space group with two crystallographically independent molecular cations in the asymmetric unit. Furthermore, the reaction of 1 with 1-alkenes gives the η2-alkene complexes in high yield.