A new 3D supramolecular array assembled by left- and right-handed helical Ni(II) coordination polymer chains based on 3,5-dinitrobenzoate and a flexible double imidazole derivative

A new nickel(II) coordination polymer with left- and right-handed helical chains [Ni(dmbbbi)(DNBA)₂(H₂O)] (1) has been obtained from hydrothermal reaction of nickel(II) nitrate with a flexible double imidazole derivative 1,1-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole) (dmbbbi) and 3,5-dinitrobenzoic acid (HDNBA). Single-crystal X-ray diffraction analysis reveals that the crystal is triclinic: a = 9.821(5) Å, b = 13.084(5) Å, c = 14.705(5) Å, α = 105.249(5)°, β = 95.688(5)°, γ = 94.273(5)°, Z = 2, V = 1804.1(13) ų, ρ_calc = 1.553 mg/m³, GOOF = 1.064, the final R = 0.0360 and wR = 0.0999. The crystal structure analysis indicates that the nickel atom is six coordinated by three oxygen atoms from two DNBA with two kinds of coordination modes, two nitrogen atoms from different dmbbbi and a coordination water molecule forming a [NiN₂O₄] subunit. The subunits are linked by dmbbbi to form a one dimensional (1D) helical coordination polymer chain and the adjacent chains are further connected by hydrogen bonding interactions to form a novel left- and right-handed helical double-chain structure. The double-chains are ultimately extended into 3D supramolecular structure through π-π stacking interactions. Moreover, thermal stability of title compound and the cyclic voltammetry behavior of compound 1 modified carbon paste electrode (1-CPE) in 1 M H₂SO₄ solution are investigated.