Synthesis,Structure and Fluorescence Sensing Property of Manganese Metal-Organic Framework Based on 5-Aminonicotinic Acid
A new three-dimension manganese(Ⅱ)metal-organic framework[Mn2(5-ana)4(H2 O)]n(namely Mn-MOF)has been successfully constructed by the reaction of 5-aminonicotinic acid(5-Hana)and MnCl2 using solution method at room temperature.The structure and properties of Mn-MOF were characterized by X-ray single-crystal diffraction,X-ray powder diffraction,elemental analysis,infrared spectroscopy,thermogravimetric analysis,ultraviolet-visible spectra and luminescent spectra.Structural analysis reveal that the as-synthesized complex crystallized in the monoclinic system and feature a binodal(2,8)-connected coordination network.The[Mn2(CO2)2(H2O)]dimeric unit acts as 8-connected node and 5-ana-ligand acts as 2-connected node.Electrostatic potential(ESP)on molecular van der Waals surface analysis of 5-ana-ligand shows that the first reactive site exists in the surface close to the oxygen atoms of carboxyl group with the ESP global minimum of-143.37 kcal·mol-1.The second and third reactive sites exist in the nitrogen atoms of pyridine ring and amino,respectively.Mn-MOF displays good thermal stability at room temperature.Fluorescence spectroscopy measurement reveals that the complex shows emission maximum at 402 nm upon 256 nm light excitation.More importantly,Mn-MOF exhibits sensing selectivity for Fe3+by fluorescence quenching with the quenching efficiency up to 98.71％,which makes it as a potential luminescent sensor for analyzing Fe3+in aqueous solution.
5-aminonicotinic acidMn(Ⅱ)crystal structuremetal-organic frameworkfluorescent sensoriron ion
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