Porphyrin–Alkaline Earth MOFs with the Highest Adsorption Capacity for Methylene Blue

A series of four porphyrin–alkaline earth metal– organic frameworks [Mg(HDCPP) 2 (DMF) 2 ] n ⋅(H 2 O) 7  n ( 1 ), [Ca(HDCPP) 2 (H 2 O) 2 ] n (DMF) 1.5  n ( 2 ), [Sr(DCPP)(H 2 O)(DMA)] n ( 3 ), and [Ba(DCPP)(H 2 O)(DMA)] n ( 4 ) was isolated for the first time from solvothermal reaction between metal‐free 5,15‐di(4‐ carboxyphenyl)porphyrin (H 2 DCPP) and alkaline earth ions. Single‐crystal X‐ray diffraction analysis reveals the 2D and 3D supramolecular network with periodic nanosized porosity for 1 / 2 and 3 / 4 , respectively. The whole series of MOFs, in particular, compounds 1 and 2 with intrinsic low molecular formula weight, exhibit superior adsorption performance for methylene blue (MB) with excellent capture capacity as represented by the thus far highest adsorption amount of 952 mg g −1 for 2 and good selectivity, opening a new way for the potential application of the main group metal‐based MOFs.