Co-MOFs Containing Flexible α,ω-Alkane-dicarboxylates and Bis(imidazole) Ligands: Synthesis, Structure, and Properties

Three structurally related flexible bis(imidazole) ligands reacted with Co(NO3)2·6H2O and succinic acid (L1) to yield three new metal‐organic frameworks {[Co(L1)(L2)]·(H2O)}n (1) [L2 = 2‐bis(imidazol‐1‐yl)ethane], {[Co(L1)(L3)](H2O)}n (2) [L3 = 1,4‐bis(imidazol‐1‐yl) butane], and {[Co(L1)(L4)]·(H2O)}n (3) [L4 = 1,4‐bis(2‐methyl‐imidazol‐1‐yl)butane], respectively. These complexes were synthesized under solvothermal conditions and characterized by elemental analysis, IR spectroscopy, single‐crystal and powder X‐ray diffraction, as well as thermal analyses. Interestingly, the ligands in these complexes exhibit different conformations and further cause three different configurations. Complex 1 shows a three‐dimensional (3D) framework, which is connected by two‐dimensional (2D) layer structures through hydrogen bonds. Complex 2 is a diamond structure with threefold interpenetration. Complex 3 is a 3D framework linked by hydrogen bonds like complex 1.