Synthesis and characterization of metal complexes with a mixed 4-imidazole-containing ligand and a variety of multi-carboxylic acids

Abstract

Six new metal–organic coordination polymers [Ni(L)(adip)(H₂O)] (1), [Co(L)(adip)]·H₂O (2), [Cd₂(L)(adip)₂] (3), [Ni(L)(oxba)]·H₂O (4), [Co(L)(obea)]·H₂O (5) and [Mn₃(L)₂(bta)₂]·2H₂O (6) were synthesized by reactions of the corresponding metal salt with the rigid ligand 1,4-di(1H-imidazol-4-yl)benzene (L) and different multi-carboxylic acids of adipic acid (H₂adip), 4,4′-oxybis(benzoic acid) (H₂oxba), 1,2-phenylenediacetic acid (H₂obea), benzene-1,3,5-triacetic acid (H₃bta), respectively. The structures of the complexes were determined by single crystal X-ray diffraction analysis. Complexes 1–4 have entangled structures with different topologies: 1 is a 2-fold interpenetrating two-dimensional (2D) network with (4,4) topology containing rare meso-helical chains; 3 is a three-dimensional (3D) uninodal 8-connected self-penetrating net; 2 and 4 are a 3-fold interpenetrating dmp 3D net. Complex 5 is a 2D network with (4,4) topology, while 6 is a typical (3,8)-connected tfz-d 3D net based on the trinuclear Mn(II) subunits. Complex 3 exhibits intense light blue emission in the solid state at room temperature and the results of magnetic measurements show that there are antiferromagnetic interactions in 6.