Hydrolysis Controlled Synthetic Strategy and Structural Variation of Hydroxyl–Metal Clusters and Metal–Organic Frameworks Based on Tripodal Ether-Linked 1,3,5-Tris(carboxymethoxy)benzene

Eight novel coordination polymers were prepared by a tripodal ether-linked tricarboxylic acid: [Mn3(TCMB)2(H2O)4]n·4nH2O (1), [Cu3(TCMB)(μ3-OH)3]n·0.5nH2O (2), [Zn3.5(TCMB)2(μ2-OH)(H2O)4]n·2nH2O (3), [Zn2(TCMB)(4-abpt)(μ3-OH)]n·nH2O (4), [Cd2(TCMB)(pdta)(EtOH)(H2O)]n·2nH2O (5), [Co3(TCMB)2(bpee)3(MeOH) (H2O)5]n (6), and [Co4(TCMB)2(bpee)2(μ3-OH)2(H2O)2]n·12nH2O (7, 8) (H3TCMB = 1,3,5-tris(carboxymethoxy)benzene, 4-abpt = 4-amino-3,5-bis(4-pyridyl)-1,2,4-triazole, Hpdta = 4-(1H-tetrazol-5-yl)pyridine, and bpee = 1,2-bis(4-pyridyl)ethene). These complexes were characterized by EA, IR, TGA, PXRD, and single crystal XRD. H3TCMB is fully deprotonated, and flexible TCMB3– ligand exhibits nine coordination modes and various conformations. Complex 1 is a 2D coordination polymer constructed from a [Mn(μ2-COO)2]n linear chain and [Mn2(μ2-COO)2(μ3-COO)2]n double chain combined by hexadentate TCMB3– spacer. Complex 2 is a beautiful 2D sandwich-like network assembled by layered [Cu3(μ3-OH)3]n network and typical tripodal hexadentate TCMB3– ligand. Complex 3 is a 3D coordination polymer constructed from two distinct heptadentate TCMB3– ligands, in which the ether oxygen atoms take part in coordination. Complex 4 exhibits a 2D double-layered network built by tetranuclear zinc cluster [Zn4(μ2-COO)4(μ3-OH)2] pillared by pentadentate TCMB3– spacer and 4-abpt linker. Complex 5 displays a 3D architecture assembled by tridentate pdta– and heptadentate TCMB3– ligand with ether–oxygen coordination. Cobalt complexes 6–8 were prepared by similar reactions at slightly different temperatures (85, 100, and 120 °C). Complex 6 is a 3D coordination polymer assembled by tridentate TCMB3– ligand. Complex 7 is a 3D porous MOF possessing tetranuclear cobalt cluster [Co4(μ2-COO)3(μ3-COO)2(μ3-OH)2] combined by hexadentate and tetradentate TCMB3– ligands. Complex 8 is a cluster-based 3D porous MOF, which is an isomer of 7 and contains a different tetranuclear cluster [Co4(μ2-COO)6(μ3-OH)2] and pentadentate TCMB3– ligand. PXRD study reveals the hydrolysis reaction mechanism. A hydrolysis controlled synthesis strategy is suggested based on Ksp values of metal hydroxides. Their thermal stabilities were investigated. Complexes 1, 2, 7 and 8 present antiferromagnetic and/or ferromagnetic interactions. Their magnetostructural correlations are studied.