Three-Dimensional Co- and Mn-MOFs Containing a C2h-Symmetric Terphenyl-3,3′-dicarboxylate Linker and Their Magnetic Properties

We report herein two new isostructural, three‐dimensional (3D) MOFs with the general formula [M(3,3′‐tpdc)(dmf)] [M = CoII (I), MnII (II)] resulting from the assembly of a metal ion and the C2h‐symmetric ditopic bridging ligand terphenyl‐3,3′‐dicarboxylate (3,3′‐tpdc). Both isostructural MOFs crystallize in the monoclinic space group C2/c. The metal ion is coordinated by four Ocarboxylate (η1:η1:µ2) and two µ2‐Odmf atoms in a distorted octahedral geometry. The metal centers are interconnected through bridging 3,3′‐tpdc and dmf ligands to form a 1D chain. The resulting 1D metal chains are further interconnected by 3,3′‐tpdc ligands to form 3D frameworks without porosity. The thermolabile dmf bridging ligands were easily removed by heating at 180 °C under vacuum for 5 h. The activated MOFs I and II exhibited very low gas uptake of N2, CO2, and H2 after removal of the dmf bridging ligands. The encapsulation of iodine guest molecules by the activated I and II was also investigated. The crystal structure of iodine‐encapsulated II was also elucidated. The coordination environment of the MnII atom in II changed as a result of the loss of dmf bridging ligands. The as‐prepared MOFs I and II exhibit weak antiferromagnetic interactions in their 1D metal chains; these magnetic interactions should mainly occur between the metal ions bridged by the short carboxylate‐based ligand and dmf oxygen atoms. Thermal removal of the bridging dmf molecules led to a change in the Mn···Mn distances in the 1D chains of II that also affected its magnetic properties. Two new magnetically active, isostructural 3D MOFs of general formula [M(3,3′‐tpdc)(dmf)] (M = CoII, MnII; 3,3′‐tpdc = terphenyl‐3,3′‐dicarboxylate) have been prepared by employing the C2h‐symmetric 3,3′‐tpdc bridging ligand. Their gas sorption and magnetic properties have been investigated.