Design of novel catalysts for synthesis of 1,5-benzodiazepines from 1,2-phenylenediamine and ketones: NH2-MIL-101(Al) as integrated structural scaffold for catalytic materials based on calix[4]arenes

Novel nanoporous composites (MIL/K-SO3H and MIL/Ks-CN) were synthesized by the encapsulation of para-sulfonatocalixpljarene (K-SO3H) and para-tert-butylthiacalixNarene (Ks-CN) with strong (-SO3H) and weak (-CN) acidic functionalities, respectively, in the aluminum(III) 2-aminoterephthalate metal organic framework (NH2-MIL-101(Al)) cavities. MIL/K-SO3H and MIL/Ks-CN materials were prepared by microwave assisted one-step synthesis in situ following to the ship in a bottle approach. According to comprehensive study, textural properties, the morphology and particle sizes of composites depend on the type of the embedded calix[4]arene molecules. Catalytic properties of MIL/K-SO3H and MIL/Ks-CN composites were investigated in the synthesis of physiologically active 1,5-benzodiazepines from 1,2-phenylenediamine and ketones (acetone, acetophenone, methyl ethyl ketone). It was found that their catalytic activity can be adjusted by surface acidity, which depends on the nature of the interactions between functional substituents in the arene bowl of calix[4]arenes and -NH2 groups in organic linkers of NH2-MIL-101(Al) framework. (C) 2018 Elsevier Inc. All rights reserved.