Syntheses, structures, and magnetic properties of six coordination polymers based on 4,5-di(4′-carboxylphenyl)phthalic acid and different bis(imidazole) bridging linkers

Six 4,5-di(4'-carboxylphenyl)phthalic acid (H4DCP) based coordination polymers (CPs), namely {[Ni(1,4-bib)(HDCP) (2)(H2O)(2)](0.5)[Ni(1,4-bib)(H2O)(4)]center dot 2H(2)O}(n) (1), [Ni(H2DCP)(1,4-bidb)(2)(H2O)](n) (2), [Co-2(DCP)(1,3-bib)](n) (3), {[Co-2(DCP)(1,4-bidb)(2)]center dot 2H(2)O}(n) (4), [Co(H2DCP)(4,4'-bibp)](n) (5), and [Co-2(DCP)(4,4'-bibp)(2)](n) (6), were synthesized under hydrothermal conditions in the presence of bis(imidazole) bridging linkers (1,3-bib = 1,3-bis(imidazol-1-yl)benzene, 1,4-bib = 1,4-bis(imidazol-1-yl)benzene, 1,4-bidb = 1,4-bis(imidazol-1-yl)-2,5-dimethyl benzene, 4,4'-bibp = 4,4'-bis(imidazol-1-yl) biphenyl). Their structures have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analysis. Single crystal X-ray diffraction analysis reveals that complex 1 is a cocrystal consisting of two independent chains. Complex 2 exhibits a traditional 2-fold 6(6)-dia parallel entangled network. Complex 3 displays a novel 3D binodal (5,7)-connected net based on binuclear {Co-2} units with the Schlafli symbol (3.4(4).5(4).6)(3(2).4(8).5(8).6(3)). Complex 4 shows a 2-fold binodal (4,4)-connected bbf net with the point symbol (6(4).8(6))(6(6))(2). Complex 5 affords a 2D (4(4).6(2))-sql net constructed from {Co-2} dinuclear units. Complex 6 displays a novel (3,8)-connected architecture with the Schlafli point symbol (4(2).5)(2)(4(4).5(10).6(8).7(4).8(2)) based on {Co-4(COO)(6)} SBUs. Magnetic studies indicate complexes 3 and 6 exhibit weak ferromagnetic and antiferromagnetic properties, respectively.