ansa-Niobocene Complexes: Synthesis and Characterization of Novel Complexes [Me2Si(η5-C5H4)2]NbCl2and [Me2Si(η5-C5H4)2]NbCl(RC⋮CR) (R = Me, Ph). X-ray Crystal Structure of [Me2Si(η5-C5H4)2]NbCl(MeC⋮CMe) | Publicación