PREPARATION AND CHARACTERIZATION OF CARBENE COMPLEXES OF IRON FROM AZOLYL AND THIENYL PRECURSORS

Azolyl and thienyl iron(II) complexes have been synthesized by the add ition of 1-phenylpyrazol-5-yllithium, hydro-4,4-dimethyloxazolin-2-yl) -2-thienyllithium, 2-(4, ihydro-4,4-dimethyloxazolin-2-yl)-3-thienylli thium or 5-(2-pyridyl)-2-thienyllithium to [Fe(cp)(CO),Cl] (cp = eta-C 5H5). Protonation or alkylation of these precursor complexes yielded t he corresponding amino(organo)-, organo(thio)- or heterometallacyclic alkoxy(amino)- and hydroxy(amino)-carbene complexes as well as compoun ds in which the ligand shows more pyridinium character. The molecular structures of the pyrazolyl complex [Fe(cp)(CO)(2)(C=CHCH=NNPh)] and t he pyrazolinylidene complex [Fe(cp)(CO)(2)(CCH=CHNHNPh)][CF3SO3] have iron-carbon bond lengths of 1.981(2) and 1.969(5) Angstrom respectivel y.