Unexpected reversal of reactivity in organic functionalities when immobilized together in a metal–organic framework (MOF)†

A mixed-ligand metal–organic framework (MOF) material composed of both amine- and hydroxyl-bearing linkers, KSU-1, was reacted with a variety of isocyanates. The hydroxyl groups reacted to a greater extent than the amines, in conflict with the previously observed relative nucleophilicities of these functionalities in the same MOF. When immobilized individually in monofunctional MOFs, the amine-functionalized linker was more reactive than the hydroxyl linker, indicating that the reactivity reversal observed in KSU-1 is due to the groups' mutual confinement within the MOF.