An efficient and highly recyclable calcium-based metal-organic framework for green cyanosilylation and hydroboration catalytic reactions

Abstract

A new calcium-based metal–organic framework (MOF), named GR-MOF-32, with chemical formula {Ca(C₂₀H₁₀N₂O₄)·2H₂O}_n ({[Ca(BCA)] 2H₂O}_n), has been synthesized using the biquinoline ligand 2,2′-bicinchoninic acid (H₂BCA) via a solvothermal method. This MOF is homologous to the previously reported GR-MOF-11 to 14 series (Sr, Y, Cd, Ba) and has been fully characterized through elemental and thermogravimetric analyses, Fourier transform infrared spectroscopy (FTIR), photoluminescence, dynamic light scattering, electrophoretic mobility, and single-crystal and powder X-ray diffraction (SCXRD and PXRD). The structural analysis reveals a highly connected framework that preserves the Janus-head topology of the ligand, similar to its homologous counterparts. The catalytic performance of GR-MOF-32 was evaluated in cyanosilylation and hydroboration reactions showing excellent recyclability, maintaining high catalytic activity all over the seven cycles in both reactions, with only a marginal loss in calcium content and no significant structural changes as confirmed by PXRD and FTIR analysis. In comparison with its homologous catalysts (GR-MOFs 11–14), GR-MOF-32 exhibited superior catalytic performance with a lower catalyst loading (0.2 mol%) and achieved full conversion for most substrates. This study expands the family of GR-MOFs with an s-block metal member such as calcium and highlights the potential of calcium-based MOFs in highly efficient catalyst in both cyanosilylation and hydroboration reactions.