One-Pot Multifunctional Catalysis with NNN-Pincer Zr-MOF: Zr Base Catalyzed Condensation with Rh-Catalyzed Hydrogenation

We describe the postsynthetic modification of Zr-based metal organic frameworks (MOFs) containing chiral NNN-pincer ligands based on aminopyridineimines, as well as the subsequent formation of (NNN)-M-Zr-MOF complexes (M=Rh, Ir). With these new multifunctional materials, we performed a cascade of condensation reactions followed by hydrogenation of the resulting double bond. If the condensation reaction occurs between an aldehyde and ethyl nitroacetate, (NNN)-M-Zr-MOF complexes catalyze the one-pot synthesis of nitroalkenes, in which Zr-IV Lewis sites play a role similar to that of the generally used Ti-IV in homogeneous catalysis. These multifunctional hybrid catalysts retain their crystalline framework even after the reaction, and they were isolated easily from the reaction mixture through filtration and reused several times without a significant degradation in activity. Moreover, there was no contribution from leached active species and conversion was possible only in the presence of the solid catalyst.