Triazine Mg-Based Phosphonate Metal-Organic Framework for ε-Caprolactone Polymerization

A novel three-dimensional metal-organic framework (MOF) based on magnesium and the triazine triphosphonate ligand has been successfully synthesized via the solvothermal method and fully characterized. Denoted as IEF-31 (IEF stands for IMDEA energy framework), its crystal structure was unveiled by single-crystal X-ray diffraction, exhibiting free P-OH groups in two coordination modes (-PO₃H₂ and -PO₃H) and an open framework with 1D channels (8 × 7 Å). This robust structure shows high thermal and chemical stability (in several catalytic-relevant organic solvents and water, pH = 2 to 10). Further, this study presents the proof of concept for using an Mg-based P-MOF as a catalyst in the ring-opening polymerization of ε-caprolactone (ε-CL) with relevance in the challenging bioplastic formation. Specifically, IEF-31(Mg) achieved notable monomer conversions and polymer molecular weights with low dispersity values (Đ ≈ 1.1), paving the way for further design and optimization of robust, efficient, and sustainable Mg P-MOFs for clean polymerization processes.