Construction and O2 sensing performance of a core–shell structured magnetic-mesoporous composite functionalized with a ruthenium complex

• A core–shell composite was constructed with Fe3O4 as core and MCM-41 as shell.
• A silane coupling ligand and its Ru(II) complex were grafted into MCM-41 shell.
• The emission of this composite decreased with increasing O2 concentrations.
• Sensitivity of 5.62 and short response time of 10 s were observed.

In the present work, a core–shell structured magnetic-mesoporous composite was functionalized with a ruthenium complex and applied for site-specific oxygen sensing purpose. Superparamagnetic ferroferric oxide and silica molecular sieve MCM-41 were used as the inner core and the outer shell, respectively. A 5H-cyclopenta[1,2-b:5,4-b′]dipyridin-5-one (Dafo) derived ligand and its corresponding Ru(II) complex were covalently grafted into MCM-41 tunnels, serving as sensing probe. Electron microscopy photos, XRD patterns, IR spectra, thermogravimetry and N2 adsorption/desorption measurement were performed to confirm and characterize this core–shell structure. It was found that emission of this composite decreased with increasing O2 concentrations, making it a potential oxygen sensing system. Sensitivity of 5.62 and short response time of 10 s were observed.

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