Two- and Three-Dimensional Divalent Metal Coordination Polymers Constructed from a New Tricarboxylate Linker and Dipyridyl Ligands

Solvothermal reactions of an unsymmetrical tricarboxylic acid ligand, biphenyl-3,3′,5-tricarboxylic acid (H3L), with cobalt, nickel, and manganese salts in the presence of 1,2-bi­(4-pyridyl)­ethane (bpa), 1,2-bi­(4-pyridyl)­ethene (bpe), and 1,3-bi­(4-pyridyl)­propane (bpp) ligands produced four new coordination polymers, namely, {[Co2(HL)2(bpa)2(H2O)]}n (1), {[Co­(HL)­(bpe)]·H2O}n (2), {[Ni­(HL)­(bpa)]·H2O}n (3), and {[Mn3L2(H-bpp)­(OH)­(H2O)2]·2H2O}n (4). Complexes 1–4 were structurally characterized by elemental analysis, infrared (IR) spectra, and X-ray single-crystal diffraction. Complex 1 exhibits a three-dimensional (3D) 4-fold interpenetrating diamondoid framework. Complex 2 is a two-dimensional (2D) layered structure with a (3,5)-connected (42.6)­(42.67.8) topology and further stacks via hydrogen-bonding interactions to generate a 3D supramolecular architecture. Complex 3 shows a 3D framework assembled by mutual interpenetration of neighboring 2D layers. Complex 4 possesses a 3D framework composed of the trinuclear [Mn3(μ3-OH)]5+ cluster nodes with a (42.6)­(42.6)­(44.62.73.85.9) topology. In addition, there exist different types of helical chains in complexes 1–3. Thermogravimetric properties of 1–4 and magnetic properties of 4 were also investigated. This study reveals that the H3L ligand can be used as a versatile building block for the construction of metal–organic frameworks.