Six Three-Dimensional Metal-Organic Frameworks with (3,4)-, (4,5)-, and (3,4,5)-Connected Nets Based on Mixed Ligands: Synthesis, Structures, and Adsorption Properties

Six new 3D metal-organic frameworks (MOFs) Cd-2(3,4-PDC)(2)(mu(2)-hmt)(H2O)(2)center dot(DMF)(2)(H2O)(2) (JUC-65), Zn-4(3,4-PDC)4(,mu(2)-hmt)(H,0)6 center dot (DMA)(4)(H2O)(5) (JUC-66), Cd-2(3,4-PDC)(2)(bipy)(2)(H2O)(2) center dot (DMA)(3)(H2O)(4) (JUC-67), Cd-2(3,4-PDC)(2)(bipy)(DMF)-(H2O). (H2O)(2) (JUC-68), Mn-2(3,4-PDC)(2)(mu(2)-hmt)(H2O)(2) (JUC-69), and Zn-8(3,4-PDC)(8)(bipy)(3)(DMA)(2)center dot(DMA)g(H2O)(8)(JUC-70) (3,4-H2PDC = pyridine-3,4-dicarboxylic acid, hmt = hexamethylenetramine, bipy = 4,4'-bipyridine, DMF = N,N'-dimethylformamide, DMA = N,N'-dimethylacetamide, and JUC = Jilin University China) have been synthesized via heterocoordination of unsymmetrical 3,4-H2PDC and transition metal ions (Cd2+, Zn2+, or Mn2+) to construct corrugated layers pillared by hmt or bipy ligands, which form various sizes and shapes of channels. Remarkably, from the topological point of view, J-UC-65-68 exhibit three undocumented types of (3,4)-connected networks, JUC-69 exhibits a rare (4,5)-connected network, and JUC-70 possesses an unprecedented (3,4,5)connected network. In addition, methanol adsorption isotherms of the activated JUC-65 and JUC-67 reveal type I behavior with approximately 87.7 mg/g and 124.8 mg/g at room temperature, respectively.