Synthesis and Two-photon Property Investigation of Benzophenone Dyes
|Keywords||Benzophenone derivatives Two-photon polymerization Two-photon absorption cross section Electrochemistry Molecular structure optimization|
Conjugated two-photon dyes have drawn of the increasing interests of people,as they can be modified easily, controllable in optical properties, and adjustable in photophysical and photochemical properties. In order to achieve two-photon polymerization at the molecular level, people try to increase two-photon absorption cross section by improving electron donor and electron acceptor strength and improving the planarity of theπ-conjugated matrix. We constructed two-photon dyes with the conjugated double bonds connecting two-photon UV initiator dye and changing the substituent groups of styrene, We synthesized nine styrene derivatives containing benzophenone segment and their spectra and two-photon properties of these novel compounds was investigated.The main research contents and results are as following:1. Nine new target compounds were synthesized, and all compounds were characterized by the melting point, 1HNMR, 13CNMR, mass spectrum and elemental analysis.2. UV-visible absorption and fluorescence emission were detected in various solvents. Absorption in the short wavelength region is mainly caused by benzophenone segment; absorption in the visible wavelength region is due to the intramolecular electron transfer. Different substituents on styrene caused the electron withdrawing ability of molecules, and the intramolecular charge transfer capabilities of different molecules were different. The infection of the solvents and the structure change on the spectral quality was studied and analyzed systematically.Fluorescence quantum yields were measured through fluorescence comparison, and fluorescence lifetime of the target compounds were detected.3. Two-photon absorption properties of compounds were investigated, and two-photon upconversion fluorescence was measured and two-photon absorption cross section was calculated through two-photon induced fluorescence method. Experimental results showed that five compounds have conversion fluorescence emission, and there was relationship between two-photon absorption cross-section and the location of benzophenone segment.4. Electrochemical behavior, thermal stability and molecular structure optimization of conjugated benzophenone type initiators were studied, and the target compounds were calculated by molecular geometry optimizations. Between electron density distribution of molecular frontier orbital energy and the substitute position, there were some dependencies.