Defect engineering of Mn-based MOFs with rod-shaped building units by organic linker fragmentation

Formation of defects with controlled concentration in Mn-MOF-74 [Mn-2(DOBDC), DOBDC: 2,5-dioxido-1,4- benzenedicarboxylic acid] and a newly synthesized metal-organic framework Mn-5(BDC-O)(2)(BDC-OH)(2) (FDM-21, BDC-OH: 2-hydroxyterephthalic acid) were systematically investigated by employing fragmented linkers with reduced coordination numbers towards Mn(II) during the synthesis. The defect engineering has resulted in missing functional groups on the framework backbone, as well as potential open metal sites in the inorganic secondary building units. The chemical form and amount of coordinating groups (-OH and/or -COOH) in the fragmented linkers have impacted the defects density of the framework significantly. Furthermore, surface area enhancement was observed in the defected Mn-MOF-74 doped with BDC-OH, compared to the defect-free Mn-MOF-74. (C) 2016 Elsevier B.V. All rights reserved.