Highly Efficient Solvent-Free Cyanosilylation of Aldehydes Catalyzed by Bilayered Two-Dimensional Metal-Organic...

While metal-organic frameworks (MOFs) are promising for heterogeneous catalysis and mechanistic investigations due to their well-defined active sites, high porosity, large surface area, and structural tunability, two-dimensional (2D) MOFs exhibit superior catalytic efficiency over three-dimensional (3D) MOFs by offering higher specific surface areas and reduced diffusion limitations, thus enhancing active site exposure and substrate accessibility. In this work, two novel bilayered 2D MOFs, Mg₃(TPHB)₂(H₂O)₆·(DMF)₁₂ (Mg-TPHB-MOF) and Mn₃(TPHB)₂(H₂O)₆·(DMF)₁₆ (Mn-TPHB-MOF), were synthesized, and their efficacy as Lewis acid catalysts in the solvent-free cyanosilylation of aldehydes was investigated. Both MOFs exhibited remarkable catalytic activity, with Mg-TPHB-MOF achieving complete conversion of benzaldehyde within 10 min at room temperature. This catalytic performance surpasses that of many previously reported MOF catalysts for the same reaction, highlighting the potential of 2D MOFs in catalysts. To gain deeper insights into the catalytic mechanism and the superior performance of Mg-TPHB-MOF, computational studies were conducted to determine the free energy profiles of the reaction pathways with and without the catalyst. The results of these calculations corroborated the experimental findings, indicating a lower energy barrier for the Mg-TPHB-MOF-catalyzed reaction. Furthermore, both MOFs demonstrated good reusability over five catalytic cycles, maintaining high conversion rates and structural integrity.