Synthesis and crystal structures of three isophthalato-bridged macrocyclic nickel(II) complexes / created by Guang-Chuan Ou, Zhi-Zhang Li, Lin Yuan and Xianyou Yuan

Three dinuclear isophthalato-bridged nickel(II) complexes formulated as [Ni(rac-L)]2(μ-IPA)(ClO4)2 (1), [Ni(RR-L)]2(μ-IPA)(ClO4)2 (2) and [Ni(SS-L)]2(μ-IPA)(ClO4)2 (3) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyc-lotetradecane, IPA = isophthalic acid) have been isolated and characterized. Single crystal X-ray diffraction analyses revealed that the Ni(II) atoms have six-coordinated distorted octahedral environments, and the isophthalato ligand bridges two Ni(II) centres in a bis bidentate fashion to form dimers in all three complexes. The monomers of {[Ni(SS-L)]2(μ-IPA)} 2+ are connected through intermolecular hydrogen bonds to generate one-dimensional left-handed helical chains in complex 3. The homochiral natures of complexes 2and3have been confirmed by CD spectroscopy.