Facile post-synthetic deamination of MOFs and the synthesis of the missing parent compound of the MIL-101 family

Abstract

A versatile method for the post-synthetic removal of primary amino groups from metal-organic frameworks (MOFs) has been developed. The method allowed the first successful synthesis of the missing parent compound of an important family of MOFs - the unsubstituted (Al)MIL-101. The material was shown to be a useful reference compound for the elucidation of the role of amino groups in the adsorption and deactivation of olefin metathesis catalysts. The chemoselectivity of the deamination is sufficient for the selective removal of NH substituents from mixed-linker MOFs bearing both NH and RCONH groups.

Ruthenium-Based Complexes Bearing Quaternary Ammonium Tags as Versatile Catalysts for Olefin Metathesis: From the Discovery to Practical Applications

“…Preliminary catalytic tests of the catalysts immobilized on the MOF were disappointing, however, and only very moderate activity was observed. The authors postulated that the catalysts were deactivated by the MOF because of the presence of poisonous ions like OH – in the MOF structure and the fact that sequestration of the Ru-bound chloride anions by the Lewis acidic MOFs may lead to much less stable and less active complexes. , Luckily, simple pretreatment of the MOF (Al)­MIL-101-NH 2 with HCl prevented the inhibition mechanism. The catalyst 9a@(Al)­MIL-101-NH 2 ·HCl was very effective in several RCM and CM transformations even with a loading of 0.5 mol % (Table ).…”

“…Under such conditions, the high stability of the catalyst 41a@(Al)­MIL-101-NH 2 ·HCl was the reason for its excellent performance (85% yield with 96% selectivity; Scheme ). , Importantly, in the case of reported ammonium-tagged catalysts immobilized in MOFs, no leaching was observed with the use of a solvent such as DCM or EA. , The use of a more polar and “green” solvent such as i -PrOH or dimethyl carbonate (DMC), however, resulted in fast removal of the physiosorbed catalyst from the MOF. In order to make the MOF-immobilized catalyst more suitable for polar and “green” solvents, Chmielewski et al developed a more robust immobilization of the ruthenium catalyst inside the MOF .…”

Multivariate metal–organic framework MTV-MIL-101 via post-synthetic cation exchange: is it truly achievable?

“…MIL-101 was originally built from the trivalent chromium ion (Cr 3+ ) along with the ditopic 1,4-benzene dicarboxylic acid linker (H 2 BDC, commercially called terephthalic acid or TPA), yielding a mesoporous structure of Mobil thirty-nine (MTN) zeolite topology. 8 Later on, isostructural analogues were synthesized using other trivalent metal cations like Fe 3+ , [9][10][11][12] Al 3+ , [13][14][15] V 3+ , [16][17][18] Ti 3+ , 19,20 and Sc 3+ . 21,22 On the other side, several BDC linkers with different functional groups were incorporated in these syntheses targeting various functionalities.…”

TMU‐16‐NH2MOF modified with organic ligands for stabilization of copper nanoparticles: An efficient and crystalline heterogeneous catalyst for the synthesis of propargyl amines derivatives under green reaction condition

“…[ 20 ] Also, one of the good advantages of these materials is their ability to become functionalized after synthesis. [ 21 ] In other words, they can be modified with various modifiers to increase additional active positions in the framework structure for specific purposes without destroying the initial crystallinity of the structure, and as a result, they will be naturally more suitable as efficient catalysis. [ 22 ] Many attempts have been made to modify the metal–organic frameworks in order to increase their efficiency to use them as heterogeneous catalysts in organic reactions.…”