Synthesis and Characterization of Cationic Iron Half Sandwich Complexes of Aminopyridines

The Lewis acid, [(η5-C5H5)Fe(CO)2]+, reacted with aminopyridines in dichloromethane under reflux to yield a new family of cyclopentadienylirondicarbonyl complexes of aminopyridine, (η5-C5H5)Fe(CO)2L]+ (where L= 2-aminopyridine, 3-aminopyridine and 4-aminopyridine). The isolated complexes were characterized by FTIR spectroscopy as well as 1H and 13C NMR spectroscopy. FTIR spectral data reveal the presence of the functional groups that correspond to coordinated aminopyridines , the organometallic fragment and the counter ion. According to FTIR, 1H and 13C NMR spectral data, 2-aminopyridine and 4-aminopyridine coordinated to the organometallic fragment through the amino group nitrogen, whereas 3-aminopyridine and 4-aminopyridine coordinated via the pyridine ring nitrogen.