Design And Synthesis Of Strong Two-Photon Aborption Properties Of Pyrimidine Derivatives Oriented By Metal Ions Sensing Responses And Biological Action

Two photon excited fluorescence (TPEF) materials are gaining increasing interest for their promising applications in various fields, such as, chemistry, physics, biologic and so on, which play an important role in the current field of the third-order non-linear optical materials. We selected 2-_iodine -4,6-dimethylpyrimidine as a central unit, which allow the tuning of the electronic delocalization along the conjugated backbone in the ground state by modulation of the twist angle between the two halves of the molecules. Eight novel organic chromophores based on pyrimidine have been designed, synthesized and characterized. Single- and two-photon absorption optical properties of the synthesized compounds were investigated both experimentally and theoretically. Furthermore, some applied studies were also carried out by using these TPA materials. The valuable results and conclusions in science were obtained. The main contents are as follows:1. Eight pyrimidine derivatives were synthesized and characterized by IR spectra, Mass spectra,'H-NMR spectra,13C-NMR spectra and Elemental analysises (C, H, N). The single-crystal structures of two compounds were analyzed, which showed that the chemical bonds in the main framework are averaged, indicating that there is a high electron delocalization in the well conjugated system. The systematic study including absorption, photoluminescence, two-photon-absorption properties in common solvent was deeply discussed. Based on typical structure data and comprehensive spectral data, the following structure-property relationships can be drawn out that the absorption and the fluorescence wavelength maximum of the SPEF and TPEF, and two-photon absorption cross sections show a similar trend with increasing electron-donating strength of the corresponding terminal groups with bent-shaped chromophores. 2. Sensing specific metal ions properties of a kind of novel bent-shaped 2-chlorinpyrimidine derivativesA series of novel bent-shaped 2-chlorinpyrimidine derivatives were employed as optical metal ion sensors for various kinds of metal cations, of which one-photon photophysical properties were investigated. The results show that 2-chlorinpyrimidine derivatives can sensor Fe3+ in either single-photon excited fluorescence in diluted solutions. Density functional calculations indicated that the balance between electron donor and acceptor linked through theπbridge is necessary to the change of single photon physical properties through strong metallization effect.3. DNA-binding properties of 2-imidazolylpyrimidine derivativesWe synthesized a kind of novel bent-shaped 2-imidazolylpyrimidine derivatives, which poses strong fluorescence property and show structurally dependent DNA cleavage activities. Pyrimidine derivatives can combine with DNA in slow rate, mainly depending on electrostatic attraction. A little change of the coordination environment greatly affect the binding ability while the compound can combine with DNA, the weak steric effect can help the molecule to embed in DNA pattern which consequently influence the binding mode.