Sc-flavanoid Complex As Fluorescent Chemosensor For The Selective Detection Of Dihydrogen Phosphate And Its Application

Dihydrogen phosphate plays an essential role in a number of chemical and biological processes.The sensitive and selective detection of H₂PO₄^-ion is of great interest to many scientific fields;Fluoride ion is one of the necessary elements for the human body,and it also plays an indispensable role in human health.Recently,the research of fluoride ion detection has become one of the hot research topics.Therefore,based on the recognition of metal ions by a series of flavonoids,this paper successfully constructed scandium-flavonoids and aluminum-flavonoids complexes as fluorescence sensors.The work focused on the specificity that scandium-flavonoids fluorescent sensors can recognize of dihydrogen phosphate ion,aluminum-flavonoids fluorescent sensors in the process of identifying fluoride ions was further improved at the same time.The main content is illustrated as follows:1.A series of flavonoids?3-3m?were synthesized.The structures of 3-3m were verified by ¹H NMR;¹³CNMR.Futhermore,investigate the metal ions sensing behavior of flavonoids?3-3m?in CH₃CN/H₂O mixed system.3,3a,3b were well recognized Sc³⁺ and Al³⁺ in the system of CH₃CN/H₂O =1:4 and their color changed from green to blue.The possible binding mode of 3,3a,3b with Sc³⁺ and Al³⁺respectively were studied by using fluorescence titration experiment,Job's plot,HRMS.Based on the Benesi-Hildebrand equation,the association constant of Sc-3,Sc-3a,Sc-3b,Al-3,Al-3a,Al-3b were calculated.2.Investigate the anions sensing behavior of Sc-3,Sc-3a,Sc-3b fluorescent sensors in the system of CH₃CN/H₂O =1:4.The selective experiments showed that SC-3,Sc-3a,Sc-3b fluorescent sensors are specific for the recognition for H₂PO₄^-;The competitive experiments showed that Sc-3,Sc-3 a,Sc-3b fluorescent sensors are good tolerance for H₂PO₄^-.The concentration titration experiments showed that the fluorescene of Sc-3,Sc-3a,Sc-3b fluorescent sensors were completely quenched under the condition of the dihydrogen phosphate ion concentration of 2.5 ?M,8 ?M,5 ?M.The quenching constant were analyzed and the quenching mechanism were concluded according to the modified Stern-Volmer equation.3.Investigate the anions sensing behavior of Al-3,Al-3a,Al-3b fluorescent sensors in the system of CH₃CN/H₂O = 1:4.The selective experiments showed that Al-3,Al-3a,Al-3b fluorescent sensors are specific for the recognition for F-;The competitive experiments showed that Al-3,Al-3a,Al-3b fluorescent sensors are good tolerance for F-.The concentration titration experiment showed that the fluorescene of Sc-3,Sc-3a,Sc-3b fluorescent sensors were completely quenched under the condition of the dihydrogen phosphate ion concentration of 9?M,10 ?M,6 ?M.The quenching constant were analyzed and the quenching mechanism were concluded according to the modified Stern-Volmer equation.4.Investigate the reversibility study of Sc-3,Sc-3a,Sc-3b fluorescent sensors upon the addition of dihydrogen phosphate ion.The experimental results showed that the sensitivity,selectivity and loss of fluorescence efficiency of Sc-3 fluorescent sensor are better than Sc-3 a,Sc-3b fluorescent sensors.5.Investigate the reversibility study of Al-3,Al-3a,Al-3b fluorescent sensors upon the addition of fluoride ion.The experimental results showed that the sensitivity,selectivity and loss of fluorescence efficiency of Al-3 fluorescent sensor are better than Al-3a,Al-3b fluorescent sensors.6.The recognition mechanism of 3,3a,3b for Sc³⁺ and Al³⁺ respectively were inferred by the infrared spectroscopy,fluorescence titration,high resolution mass spectrometry and Job's plot methods.7.Investigate the pH test paper application of Sc-3,Sc-3a,Sc-3b,Al-3,Al-3a,Al-3b complexes.It showed that Sc-3,Sc-3a,Sc-3b complexes have good reversibility between H₂PO₄^-and Sc³⁺ ions;Al-3,Al-3a,Al-3b complexes have good reversibility between-and Al³⁺ ions at the same time.