Synthesis And Application Of Anthraquinone Organic-Inorganic Hybrid Mesoporous Materials In Ternary Deep Eutectic Solvent

In this paper,an anthraquinone compound-1,8-dihydroxyanthraquinone(DHAQ)with luminescent properties was selected,and reacted with 3-isocyanatopropyltriethoxysilane(IPTES)to synthesize organosiloxane precursor(DHAQ-Si).Organic-inorganic hybrid periodic mesoporous materials(DHAQ-PMOs)were synthesized with DHAQ-Si and tetraethyl orthosilicate(TEOS)as mixed silicon source and CTAB as structure directing agent in ternary deep eutectic solvent(DES).It is proved by experiments that DHAQ has been successfully connected to mesoporous materials at the molecular level.Therefore,DHAQ-PMOs not only have ordered mesoporous structure,but also maintain the luminescence properties of DHAQ organic groups.The main study details are as follows:(1)DHAQ is a compound with both excited state intramolecular proton transfer(ESIPT)and intramolecular charge transfer(ICT)effects,so it exhibits fluorescence emission under UV lamp irradiation.The effect of solvent on the optical properties of DHAQ was investigated by UV-Vis absorption spectra and fluorescence emission spectra,and the selectivity of DHAQ to metal ions was studied in DMSO:H2O=9:1 solution.The results show that DHAQ can detect Al3+ and Zn2+and its limit of detection are 7.95×10-8 M and 2.35×10-8 M,respectively.The Job’s plot experiments show that the coordination ratios of DHAQ to Al3+and Zn2+are 1:1 and 1:2,respectively.Although DHAQ has good selectivity for Al3+and Zn2+,DHAQ as an organic fluorophore is susceptible to various factors and has weak anti-interference during the detection process,so DHAQ needs to be modified.(2)On the basis of the work in Chapter 2,DHAQ-Si was synthesized by modifying DHAQ with IPTES.Next,DHAQ-PMOs were synthesized in DES with DHAQ-Si and TEOS as mixed silicon source and CTAB as structure directing agent.A series of experiments show that DHAQ has been successfully embedded into the framework of mesoporous materials.The rigid framework of DHAQ-PMOs makes the chemical properties of DHAQ more stable and improves the luminous efficiency of DHAQ.The UV-Vis absorption spectra and fluorescence emission spectra of DHAQ-PMOs in different organic solvents show that the optical properties of DHAQ-PMOs are very different in protic and aprotic solvents,which may be related to the ICT effect in DHAQ-PMOs.In addition,this paper discussed the response of DHAQ-PMOs to metal ions.In the solution of CH3OH:H2O(1:9,V/V,10 mM HEPES buffer,pH=7.4),DHAQ-PMOs can realize the specific response to Cu2+,and have excellent anti-interference performance.The limit of detection can be reached 2.39×10-9 M.Compared with the original organic fluorophore DHAQ,DHAQ-PMOs exhibited enhanced anti-interference in the detection of metal ions with an order of magnitude lower detection limit.The coordination between DHAQ and Cu2+was proved by fluorescence polarization experiments,Fourier transform infrared spectroscopy(FTIR),Job’s plot,density functional theory(DFT),X-ray photoelectron spectroscopy(XPS)and so on.In order to further study the practical application of DHAQ-PMOs,DHAQ-PMOs were co-cultured with hepatoma cells HepG2,and the cells exhibited bright red fluorescence under laser confocal microscope.The addition of Cu2+ could quench the fluorescence of the material in living cells.The above results show that DHAQ-PMOs can be used as a solid-state sensor to detect Cu2+and realize the detection of Cu2+ in living cells,which indicates that DHAQ-PMOs have wide application potential in practical and biomedical fields.