Syntheses, structures, and magnetic properties of five coordination polymers constructed from biphenyl-3,4′,5-tricarboxylic acid and (bis)imidazole linkers

Abstract

Five coordination polymers (CPs), namely {[Ni_1.5(BPT)(1,4-bib)₂(H₂O)]·(1,4-bib)_0.5·2H₂O}_n (1), {[Co₂(BPT)(1,3-bimb)(μ₃-OH)]·H₂O}_n (2), {[Zn(HBPT)(1,3-bimb)]·H₂O}_n (3), {[Co₂(BPT)(H₂BPT)(4,4′-bibp)₂]·2H₂O}_n (4), and [Mn_2.5(BPT)(4,4′-bibp)_2.5(SO₄)(H₂O)]_n (5) (H₃BPT = biphenyl-3,4′,5-tricarboxylic acid, 1,4-bib = 1,4-bis(1H-imidazol-1-yl)benzene, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl)benzene, and 4,4′-bibp = 4,4′-bis(imidazol-1-yl)biphenyl), were synthesized under hydrothermal conditions. Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric (TG) analyses. Complex 1 exhibits unprecedented 2D + 2D → 3D parallel entangled networks consisting of trilayer (3,4,6)-connected (4⁴·5⁴·6⁶·8)(5·6⁴·8)₂(5²·6²) sheets. Complex 2 displays a 3D (3,10)-connected 3,10T9 net based on tetranuclear {Co₄(μ₃-OH)₂} clusters with the Schläfli symbol (4¹⁸·6²⁴·8³)(4³)₂. Complex 3 shows an interesting 1D tube-like chain consisting of Zn₂(1,3-bimb)₂ loops. Complex 4 affords a 2D (4⁴·6²)-sql net constructed from {Co₂} dinuclear units. Complex 5 displays a 3D 6-connected (4¹²·6³)-pcu net consisting of α-Po primitive cubic nets based on {Mn₅(SO₄)₂} clusters. Moreover, magnetic studies indicate that complexes 2, 4 and 5 show antiferromagnetic properties.