This work demonstrates a robust and selective strategy for the controlled delivery of carbon monoxide (CO) using a hafnium-based metal-organic framework, UiO-66(Hf), as a host matrix for molybdenum hexacarbonyl (Mo(CO)₆). The composite material, Mo(6.0)/UiO-66(Hf), was prepared through post-synthetic adsorption in 1,2-dichloroethane, resulting in a uniform distribution of Mo species within the MOF pores, as confirmed by SEM-EDS elemental mapping. Powder X-ray diffraction (PXRD) and scanning electron microscopy revealed that neither the crystallinity nor the morphology of the UiO-66(Hf) framework was disrupted by the loading process. Nitrogen physisorption at 77 K showed a 20% decrease in micropore volume due to pore occupation by Mo(CO)₆, while the overall isotherm profile remained consistent with a microporous material.
Thermogravimetric analysis under nitrogen identified a weight loss step at 162 °C, attributed to the decomposition of Mo(CO)₆ into subcarbonyl species, while the degradation of organic linkers occurred at higher temperatures (525 °C), confirming the high thermal stability of the framework. FT-IR spectroscopy detected characteristic bands at 592 cm⁻¹, 1983 cm⁻¹, and a shoulder at 2018 cm⁻¹, assigned to the (Mo–C–O) and symmetric CO stretching modes of Mo(CO)₆, providing direct evidence of successful encapsulation. Solid-state ¹³C¹H CP MAS NMR further confirmed the presence of intact Mo(CO)₆ via a sharp resonance at 199.0 ppm.
The photoresponsive CO release behavior was evaluated using the myoglobin (Mb) assay under simulated physiological conditions (37 °C, pH 7.4 buffer). In darkness, no spectral changes were observed, indicating excellent stability and negligible spontaneous release.EMI48 Technical Information Upon UV irradiation (365 nm), a time-dependent increase in carboxymyoglobin (COMb) formation was recorded, reaching a maximum of 0.Fas Ligand Proteincustom synthesis 26 mmol CO per gram of material after 270 minutes, corresponding to a photo-releasing efficiency of 42%.PMID:35045889 Importantly, leaching studies revealed that less than 1% of Mo was released into solution over six hours of irradiation, demonstrating exceptional retention of both the parent complex and its reaction byproducts. Post-irradiation PXRD and FT-IR analyses showed only minor structural and chemical modifications, underscoring the resilience of the UiO-66(Hf) framework. These results highlight the potential of this system for safe, targeted, and light-triggered CO delivery in biomedical applications.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com