Synthesis of a conjugated molecular triad based on 9,9-dioctyl-9H-fluorene for fluorescence sensing to determine mesotrione
Authors:   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Nguyen Thao Phuong Le , Bui Thao Thanh ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Doan Bao Kim ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Bui Linh Phuong ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Luu Tam Hoang ,   Faculty of Materials Technology, Ho Chi Minh City University of Technology, Vietnam National University Ho Chi Minh City,01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Tran Chau Duc ,   Faculty of Materials Technology, Ho Chi Minh City University of Technology, Vietnam National University Ho Chi Minh City,01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Tran Tung Viet Tuan ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam, Yokozawa Tsutomu ,   Department of Materials and Life Chemistry, Kanagawa University, 27-1 Rokukakubashi, Yokohama, Japan, Nguyen Ha Tran ,   National Key Laboratory of Polymer and Composite Materials, Ho Chi Minh City University of Technology,  Vietnam National University Ho Chi Minh City, 01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam,   Faculty of Materials Technology, Ho Chi Minh City University of Technology, Vietnam National University Ho Chi Minh City,01 Street 2, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam
Published: March 2023

A conjugated molecular triad based on pyrene and 9,9-dioctyl-9H-fluorene has been successfully synthesised via the Suzuki cross-coupling reaction with yield of 48%. In this polymerization, the Pd(PPh3)4 has been used as the catalytic in the presence of K2CO3 as base in a mixture of toluene/ethanol/H2O at 80oC under N2. The chemical structures of the conjugated molecules were determined via Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H-NMR) that proved the chemical structure of 1,1’-(9,9-dioctyl-9H-fluorene-2,7-diyl)dipyrene. The optical properties of the molecules were investigated via UV-Vis in different concentration that exhibited the maximum absorption of 340 nm. The conjugated molecular triad also have been investigated by fluorescence spectroscopy that showed a mission peak at 475 nm under the excitation of 350 nm of wavelength. In addition, the 1,1’-(9,9-dioctyl-9H-fluorene-2,7-diyl)dipyrene exhibited a fluorescence quenching as a chemosensor in the presence of mesotrione, a nitroaromatic herbicide. This phenomenon proved the efficient energy and electron transfer from a photo-excited pyrene moiety to the ground state electron-deficient mesotrione as a result of Forster resonance energy transfer (FRET) mechanism.