Zirconium-Metalloporphyrin PCN-222: Mesoporous Metal–Organic Frameworks with Ultrahigh Stability as Biomimetic Catalysts

Home > News > Zirconium-Metalloporphyrin PCN-222: Mesoporous Metal–Organic Frameworks with Ultrahigh Stability as Biomimetic Catalysts

Summary:
The authors from Texas A&M University developed PCN-222(Fe), a zirconium-metalloporphyrin mesoporous MOF featuring 3.7 nm 1D channels and ultrahigh acid/base stability, achieving 16.1 min⁻¹ turnover frequency in biomimetic peroxidase catalysis that outperforms free hemin seven-fold.

Background:
1. To address the self-dimerization and degradation of natural heme catalysts in aqueous oxidations, previous researchers immobilized heme on supports or synthesized dendrimers, yet active-site dilution and complex synthesis remained drawbacks.
2. The authors proposed integrating Fe-TCPP struts directly into a Zr-based MOF backbone, creating PCN-222 with dense, well-exposed porphyrin centers protected by a mesoporous crystalline framework.

Research Content:
1. Synthesis: Solvothermal reaction of ZrCl₄, Fe-TCPP and benzoic acid modulator in N,N-diethylformamide at 120 °C for 48 h yielded dark-brown needle crystals (46 % yield).
2. Characterizations:
   1) BET 2200 m² g⁻¹; type-IV isotherm with 1.3 nm micro- and 3.2 nm mesopores (DFT).
   2) SEM/TEM show single-crystal needles ~10 µm long; PXRD confirms P6/mmm symmetry.
   3) XPS verifies Fe³⁺ in porphyrin; framework survives boiling water & conc. HCl 24 h.
3. Application: Peroxidase-like oxidation of pyrogallol, TMB and o-phenylenediamine; kcat = 16.1 min⁻¹, Km = 0.33 mM, both superior to free hemin and comparable to HRP.
4. Mechanism: Zr₆(µ₃-OH)₈ clusters provide strong Zr–O bonds and chelation stabilizes Fe-porphyrin; 3.7 nm mesochannels prevent dimerization, minimize diffusion resistance and grant full access to the high-density active sites (1 site per 1286 Da).

Outlook:
PCN-222 establishes a universal platform for robust, reusable biomimetic catalysts and opens a route to enzyme-mimic MOFs scalable for industrial biocatalysis and sensing.

Zirconium-Metalloporphyrin PCN-222: Mesoporous Metal–Organic Frameworks with Ultrahigh Stability as Biomimetic Catalysts
Authors: Dawei Feng, Zhi-Yuan Gu, Jian-Rong Li, Hai-Long Jiang, Zhangwen Wei, Hong-Cai Zhou
DOI: 10.1002/anie.201204475
Link: https://onlinelibrary.wiley.com/doi/10.1002/anie.201204475

The above review is for academic progress sharing. For any errors or copyright issues, please contact us for correction or removal.