Synthesis And Property Investigation Of Distyrylbenzene Based Two-Photon Sensor

7-phenyl-1-oxa--4,10-dithia-7-aza-cyclododecane(NS20), 10-phenyl-1,4-dioxa-7,13-dithia-10-aza-cyclopentadecane(NS202) and N,N-bis(2-acetyloxyethyl)aniline (DE) were synthesized as receptors. Six distyrylbenzene based two-photon sensors: DMNS20, DMNS202, DMDE and DPNS20, DPNS202, DPDE were obtained through Vilsmeier reaction and Wittig-Horner reaction. One end of the sensor is N,N-dimethylamino (DM) or N,N-diphenylamino (DP) respectively.The crystal structure of DMNS20 was analyzed by single crystal X-ray diffraction. The result shows that both of the two C-C double bond are exist as a trans configuration. The dihedral angle between benzene ring was 24.6°and 37.5°respectively.The absorption and emission spectra were analyzed in acetonitrile solvent. The maximum absorption of the six sensors is around 460 nm, and the emission around 600 nm. With a two-photon excitation between 750 nm and 900 nm, fluorescence was also found at 600 nm with a weaker intensity. This can be a powerful proof of the two-photon absorption property of the sensors.Fluorescence spectra responds of all six sensors upon the addition of various metal ions were investigated. The addition of Ag⁺, Zn²⁺ or H⁺ to DMNS20, DMNS202 and DMDE induced a new emission peak at 420 nm, the intensity is 20 times stronger than the 600 nm emission of pure sensor, the original 600 nm emission peak become weaker or disappears. No emission peak was found for sensor DPNS20, DPNS202 and DPDE upon the addition of Ag⁺, Zn²⁺ or H⁺. The N,N-dimethylamino group and the receptor is supposed to interact with the metal ions or proton. The interaction makes both nitrogen atoms in two ends electron withdrawing groups. Then the molecular structure are changed from D-Ï€-A-Ï€-D to D-Ï€-A-Ï€-A or A-Ï€-A-Ï€-A in different metal ion concentration. Molecules with A-Ï€-A-Ï€-A structure show strong emission at 420 nm.Generally, six distyrylbenzene based two-photon sensors were synthesized. Their recognition to metal ions were investigated. DMNS20, DMNS202 and DMDE show selective fluorescence responds to Ag⁺ and Zn²⁺. A new strong emission peak was observed at 420 mother recognition principles were speculated.