Post synthetic exchange enables orthogonal click chemistry in a metal organic framework

Abstract

Biphenyl-4,4’-dicarboxylic acid derivatives containing either azide or acetylene functional groups were inserted into UiO-67 metal organic frameworks (MOFs) via post synthetic linker exchange. Sequential and orthogonal click reactions could be performed on these modified MOFs by incubating the crystals with small molecule substrates bearing azide or acetylene groups in the presence of a copper catalyst. 1H NMR of digested MOF samples showed that up to 50% of the incorporated linkers could be converted to their “clicked” triazole products. Powder X-ray diffraction confirmed that the UiO-67 structure was maintained throughout all transformations. The click reaction efficiency is discussed in context of MOF crystallite size and pore size. As the incorporation of clicked linkers could be controlled by post synthetic exchange, this work introduces a powerful method of quickly introducing orthogonal modifications into known MOF architectures.

Complete and Versatile Post‐Synthetic Modification on Iron‐Triazole Spin Crossover Complexes: A Relevant Material Elaboration Method

“…The PSM method is also an attractive method for its possibility to create a diversity of materials from the same "parent" material. [23][24][25][26][27] One of the limitation of such synthetic pathway is the fact that it often implies a solid-liquid reaction. In a first approx-imation, reaction in which all reagents are not in the same phase is expected to be less efficient than one in a homogeneous media.…”

“…In addition to the advantages on chemical transformations, PSM reactions can provide a template for the solid state structure, in other words, main features of solid-state structures present in the "parent" materials can be preserved in the functionalized material in contrast with direct methods. [2,26,27,36,37] Finally, Wang et al [2] demonstrated that the PSM method leads to a more homogeneous material when MOF are incorporated in polymers. Indeed, the authors explain this observation by an increase in compatibility between the MOF and the polymer due to the formation of chemical bonds between the two entities.…”

“…This is illustrated by the preparation of functionalized MOF in which the thermal process required to form the material is not compatible with a diversity of organic functions. The PSM method is also an attractive method for its possibility to create a diversity of materials from the same “parent” material [23–27] …”

“…synthesized Ti‐MOF complexes and then associated them by the coordination of the amino functional group on the Ti‐MOF to transition metals such as Ni or Cu. In addition to the advantages on chemical transformations, PSM reactions can provide a template for the solid state structure, in other words, main features of solid‐state structures present in the “parent” materials can be preserved in the functionalized material in contrast with direct methods [2,26,27,36,37] . Finally, Wang et al [2] .…”

Uniform and simultaneous orthogonal functionalization of a metal–organic framework material

“…While the construction of MOFs with orthogonally reactive linkers has been reported, the use of identical coordination chemistry resulted in randomly distributed functionality. [18][19][20] Our goal in this work is to demonstrate an orthogonal functionalization strategy that not only yields uniformly functionalized MOFs, but that can also do so via multiple paths, including via a simultaneous reaction (Figure 1B). Multipath reactions allow us to react the -OH first, providing greater flexibility in reactant choice for the second reaction.…”