Zinc Complexes with the N‑Donor-Functionalized Cyclopentadienyl Ligand C5Me4(CH2)2NMe2

The amino-functionalized zincocene [ZnCpN2] (4; CpN = C5Me4(CH2)2NMe2), which is the first mononuclear zincocene with two donor-functionalized cyclopentadienyl ligands, was prepared through treatment of KCpN with ZnCl2 in a 2/1 ratio. X-ray crystallography reveals the chelating binding mode of each CpN ligand via an η1-coordinated Cp ring and the amino group. The structural dynamics of 4 in solution were examined by variable-temperature 1H NMR spectroscopy, and decoalescence of the NMR signals was found at low temperatures. Reacting 4 with [ZnR2] (R = Et, Cp*) yields the monocyclopentadienyl and mixed-ring donor-functionalized complexes [ZnEtCpN] (5) and [ZnCp*CpN] (6). In contrast to the reaction of KCpN with ZnCl2 in a 2/1 ratio, which yields the zincocene 4, the reaction in a 1/1 ratio results exclusively in the formation of the chlorido-bridged dimer [Zn­(μ-Cl)­CpN]2 (7). This compound is comparable to [Zn­(μ-Cl)­Cp*­(THF)]2 (8), which crystallizes from a THF solution of equimolar amounts of [ZnCp*2] (1) and ZnCl2.