Novel complexes of nickel with N-heterocyclic ligands and the hemilabile [2-(dimethylamino)ethyl]cyclopentadienyl group

Starting out from [CpNNiI] (1), three new derivatives with polar σ(Ni–N) bonds of the type [CpNNiL] (CpN = [2-(N,N-dimethylamino)eth-1-yl]cyclopentadienyl; L = carbazolato, 3; maleimidato, 4; phthalimidato, 5) were synthesized by salt elimination. The new compounds were characterized by 1H and 13C{1H} NMR spectroscopy, elemental analysis, mass spectrometry and, in the case of 3 and 5, by single crystal X-ray diffraction studies. The presence of electron withdrawing groups R at the negatively polarized N-atom, allowing for charge delocalization strongly contribute to the stability of amido and/or imidato complexes at the CpNNi fragment.