The Photophysical Properties And Possible Applications Of Two Heteroatom-Containing π-Conjugated Triaryl Compounds

Manyπ-Conjugated triaryl compounds show excellent photoelectric properties.Aromatic rings with electron-donating ability are prone to form intramolecular charge-transfer compounds when attached to electron-deficient central structures.These compounds usually exhibit high luminescence efficiency.Their luminescence behaviors are more sensitive to the changes in the surrounding microenvironment.Researchers can change the central atom or polyatomic structure and decorate different aromatic groups to achieve the detection ability of microenvironmental changes.Organic fluorescent probes for temperature have attracted increasing attention due to their extremely high spatio-temporal resolution.Some triarylboron derivatives can change their luminescent color at different temperatures,and the related mechanism is controversial.In addition,fluorescent anti-counterfeiting inks are widely used to prevent forgery in commercial paper,premium merchandise packaging,and labels due to their ease of verification prevention of forgery.Pattern printed with the ink are invisible in sun light but visible when excited by the appropriate light.Research on water-based fluorescent anti-counterfeiting inks has attracted much attention with the worldwide enforcement of green printing standards.This thesis investigates the thermochromism luminescence mechanism of a triarylboron compound and the ion detection ability of a triaryltriazine compounds,as well as the latter’s fluorescent anti-counterfeiting properties as follows.(1)Study of the thermochromic luminescence mechanism of a triarylboron compound.We selected a representative one-component ratiometric luminescence(SCRE)compound,dipyrenyl-1-(2,4,6-triisopropylphenyl)borane(DPTB)for several spectroscopic experiments,and carried out a variety of time-dependent density flooding theory(TDDFT)along with coupled-cluster(CC)calculations to investigate the mechanism of its thermoluminescence.The computational results show that the CC rather than the TDDFT approach gives a reasonable explanation for the experimental results.Therefore,the thermochromic luminescence is now attributed to molecularly conformational thermal equilibrium occurring in both excited and ground states.The specific conformer with the characteristic of intramolecular excimer play a crucial role in the chromism behavior.(2)Synthesis and application of triarytriazine compound.A new triarytriazine compound 2,4-diphenyl-6-pyren-triazine(DPPT)was synthesized from1-pyreneboronic acid and 2-chloro-4,6-diphenyl-1,3,5-triazine.We characterized the molecular structure of DPPT with ~1H NRM and mass spectrometry.Because DPPT has a high fluorescent quantum yield and can be selectively quenched by iron ions in good solvents,we have prepared fluorescent probes for selectively detecting iron ions and studied their detection performances.In addition,because the DPPT in the aggregation state will form excimer,luminescence from blue light(dispersion state)change to green light(concentration state),and the fluorescence of this system was selectively quenched by iron ions and could be restored by addition of adenosine 5′-triphosphate(ATP),we made the hydrophobic DPPT dissolved in the F127 glue beam,to prepare a the triple anti-counterfeiting aqueous systems of temperature tunable multicolor fluorescence,fluorescence quenching by iron ions,and fluorescence recovery through ATP.