Construction of one-dimensional homochiral helical supramolecular stereoismers using chiral macrocyclic nickel(II) complexes as building blocks

•The helicity of one-dimensional chains is much dependent on the chirality of the building blocks.•The molecular building blocks may change the helicity of helical chain, but not affect the displayed Cotton effects.•Two different one-dimensional helical chains were obtained from the same reactions.

One one-dimensional right-handed helical chain of {[Ni(RR-L)][Ni(CN)4]·2H2O}n (Δ-2·(2H2O)n) was successfully constructed by the reaction of the [Ni(α-RR-L)]2+ and [Ni(CN)4]2− in acetonitrile/water (1:1) (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane), and another two one-dimensional left-handed helical chains of {[Ni(SS-L)][Ni(CN)4]·2H2O}n (Λ-2·(2H2O)n) and {[Ni(SS-L)][Ni(CN)4]·1.25H2O}n (Λ-3·(1.25H2O)n) were obtained from the reaction of [Ni(α-SS-L)]2+ with [Ni(CN)4]2−. The reaction of [Ni(CN)4]2− building blocks with [Ni(α-SS-L)]2+ in acetonitrile/methanol (1:1) gave a one-dimensional left-handed helical chain of {[Ni(SS-L)][Ni(CN)4]·MeCN}n (Λ-2·(MeCN)n). In all supramolecular isomers, the [Ni(RR-L)]2+/[Ni(SS-L)]2+ cations are alternately bridged by [Ni(CN)4]2− anions through cyano-groups to form one-dimensional helical chains. The homochiral natures of four complexes were confirmed by the results of solid-state circular dichroism spectra measurements.

Graphical abstractFour supramolecular isomers with one-dimensional helical chains of -2·(2H2O)n, Λ-2·(2H2O)n, Λ-2·(MeCN)n and Λ-3·(1.25H2O)n were obtained by the reactions of the [Ni(α-RR-L)]2+/[Ni(α-SS-L)]2+ and [Ni(CN)4]2−. The homochiral natures of four complexes were confirmed by the results of solid-state circular dichroism spectra measurements.Figure optionsDownload full-size imageDownload as PowerPoint slide