Oligopeptide grafting in MOF for enantioselective applications
Résumé
Grafting of chiral species such as amino-acids inside MOF cavities [1] allows designing enzyme-like materials [2]. Covalent post-synthetic modification is a powerful tool to increase the sophistication degree in porous materials. We report here, for the first time, the application of a microwave-assisted solid phase peptide coupling strategy in order to immobilize chiral amino-acids inside amino-functionalized MOF frameworks. Through the use of microwave irradiation, the peptide coupling is 500 times faster with a gain in active site loading. Both enantiopure L-proline and D-proline-glycine are successfully anchored into the MOF cavities through a microwave-assisted coupling-deprotection sequence. The coupling was performed on various MOF structures such as MIL-101, MIL-68 and UiO-66. The characterization showed that after coupling the structures remain crystalline and porous. This new microwave-assisted solid-phase peptide coupling methodology opens new perspectives for anchoring chiral bio active species within MOFs for molecular recognition, bio-sensing applications and asymmetric catalysis.