Tuning structural topologies of four Ni(ii) coordination polymers through modifying the substitute group of organic ligand

Abstract

In order to investigate the effect of the substituent group of an organic ligand on the structures of coordination polymers, four new Ni(II) coordination polymers based on 5-position substituted 1,3-benzenedicarboxylate and N-donor auxiliary ligands, namely, [Ni(5-CH₃-ip)(L₁)(H₂O)]_n (1), [Ni(5-NO₂-ip)(L₁)₂(H₂O)]_n (2), [Ni(5-CH₃-ip)(L₂)_1.5]_n (3) and {[Ni₂(5-NO₂-ip)₂(L₂)₂(H₂O)₂]·(H₂O)}_n (4) (5-CH₃-ip = 5-methyl-1,3-benzenedicarboxylic acid, 5-NO₂-ip = 5-nitro-1,3-benzenedicarboxylic acid, L₁ = 1,4-bis(imidazol-1-yl)benzene and L₂ = 1,4-bis(1-imidazol-yl)-2,5-dimethyl benzene), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 features a two-dimensional (2D) layer structure. Complex 2 possesses a three-dimensional (3D) 5-connected net giving an interesting 3-fold interpenetrating architecture. Complex 3 shows a 5-connected topological framework with point symbol (4².6⁸). Complex 4 displays a 6-connected 3D self-penetrating topological network with point symbol (4⁸.5².6⁵). Structural diversities indicate that the substituent group of organic ligands play important roles in tuning the structures of these complexes. Furthermore, magnetic properties of complexes 1 and 4 are investigated.