Metal–organic frameworks(MOFs)permit significant structural diversity and functional design flexibility due to the various combinations of metal centers and different organic linkers.However,their combinations genera...Metal–organic frameworks(MOFs)permit significant structural diversity and functional design flexibility due to the various combinations of metal centers and different organic linkers.However,their combinations generally adhere to the classic hard and soft acid and base(HSAB)theory.This makes it impossible to directly synthesize desired MOFs with converse Lewis types of metal ions and ligands.Herein,we present a novel Cu(II)ion cleavage reduction strategy that circumvents the limitations of HSAB theory.We demonstrate this approach by utilizing a metastable CuH_(2)DOBDC MOF,whose inherent structural instability facilitates structural transformations and phase transitions in response to external stimuli.By leveraging the unique structure of ascorbic acid to reduce Cu(II)ions and cleave the H_(2)DOBDC^(2−)linkers,we successfully fabricate a new Cu_(2)H_(2)DOBDC structure composed of a soft acid Cu(I)and a hard base(H_(4)DOBDC).The resultant Cu_(2)H_(2)DOBDC integrates the characteristics of mesoporosity and hierarchical nanostructures,resulting in excellent mass transfer and abundant accessible Cu(I)active sites,which endows the material with outstanding catalytic activity in the azide–alkyne cycloaddition reaction.This is the first example of fabricating stable single-phase Cu(I)-carboxylic acid MOFs with nearly all Cu(I)ions,and this work offers a new perspective on the creation of a new category of MOFs with soft-acid and hard-base type coordination bonds.展开更多
基金supported by the National Natural Science Foundation of China(22175030 and 22365025)the Open Project of the State Key Laboratory of Supramolecular Structure and Materials(sklssm 202406).
文摘Metal–organic frameworks(MOFs)permit significant structural diversity and functional design flexibility due to the various combinations of metal centers and different organic linkers.However,their combinations generally adhere to the classic hard and soft acid and base(HSAB)theory.This makes it impossible to directly synthesize desired MOFs with converse Lewis types of metal ions and ligands.Herein,we present a novel Cu(II)ion cleavage reduction strategy that circumvents the limitations of HSAB theory.We demonstrate this approach by utilizing a metastable CuH_(2)DOBDC MOF,whose inherent structural instability facilitates structural transformations and phase transitions in response to external stimuli.By leveraging the unique structure of ascorbic acid to reduce Cu(II)ions and cleave the H_(2)DOBDC^(2−)linkers,we successfully fabricate a new Cu_(2)H_(2)DOBDC structure composed of a soft acid Cu(I)and a hard base(H_(4)DOBDC).The resultant Cu_(2)H_(2)DOBDC integrates the characteristics of mesoporosity and hierarchical nanostructures,resulting in excellent mass transfer and abundant accessible Cu(I)active sites,which endows the material with outstanding catalytic activity in the azide–alkyne cycloaddition reaction.This is the first example of fabricating stable single-phase Cu(I)-carboxylic acid MOFs with nearly all Cu(I)ions,and this work offers a new perspective on the creation of a new category of MOFs with soft-acid and hard-base type coordination bonds.
