Fluorescent Probes Based On Multi-aryl Substituted1,3-butadiene Derivatives

Temperature plays a critical role in tremendous physical, chemical, and biologicalprocesses. Imperceptible changes in temperature need to be precisely identified frommolecular level to industrial applications, among others, chemical reactions, solid-statephysics, material science, and aerospace industries. Accurate detection of temperature istherefore of great importance for understanding the underlying mechanism of theseprocesses.Thermometersbased on thermal expansion, thermocouples and Infrared detectiontechnology are most commonly used in daily life. However, these thermometers have theirintrinsic limitations in harsh environment, such as strong magnetic field.Infrared detectiontechnology based on the infrared radiation energy of the objects have been widely used inhigh temperature range, application in low temperature is limited.These facts prompt peopleto explore more intriguing materials and technologies for probing temperature.The detection of explosives is vital to the national security.Five-membered energeticheterocyclic compounds (5MR-EHCs), among the most important high-energy-densitymaterials, are widely used as dynamites, explosives and propulsion agents for a myriad ofmilitary and civil applications. Five-membered energetic heterocyclic compounds(5MR-EHCs) with high nitrogen content offer remarkable advantages over conventionalenergetic compounds, such as high heat of formation, large density, good oxygen balance,and rather low sensitivity toward friction and impact. It is therefore vital to sense the5MR-EHCs.So far, high performance liquid chromatography (HPLC), ion migrationspectrometry (IMS), Raman spectroscopy and fluorescence methodare mainly used inexplosives detection. The fluorescence detection method with high sensitivity, low cost andsimple pretreatment has been energetically pursued recently, however, most of explosivesdetection is based on fluorescence quenching, and progress in fluorescence turn-on isrelatively slow.In this thesis, the author focuses on the design, synthesis, and properties of1,3-butadienederivativesbasedfluorecentprobe in detection of cryogenic temperature andfive-membered heterocyclic compound. The content of this thesis is summarized inchapters:In Chapter2, the author synthesized a molecule with electron push-pull structure(MCBD) by yne-yne coupling and Suzuki coupling recations. It exhibits uniquethermochromic behaviors in three different organic solutions.MCBD exhibits temperature-dependent obvious luminescence intensity and emission wavelength change,broad dynamic range of responses. Then, we elucidated the possible mechanisms, i.e.excimer or exciplex formation, intramolecular charge transfer, and varying solventrelaxation process, for distinct thermochromic behaviors of MCBD in three solvationsenvelops. Sensor arrays that can directly read out temperature by naked eye wasconstructed based on the phenomenon, the accuration was improved by thecross-correlativematrix. Futhermore, this molecular probe can be applied to mappingtemperature on the surface of materials without invasion and contamination.In Chapter3, the author developed a method of highlysensitive and selective detectionof explosives such as five-membered-ring energetic heterocyclic compounds (5MR-EHCs)in a few seconds with low detection through emission shift and/or turn-on. The strategy isbased MOF probes for turn-on detection applications by employing aryl substituted1,3-butadiene carboxylic acid derivatives with the aggregation-induced emission featureand metal nodes with distinct outer-shell electron configurations. When altering the metalion from Mg2+to Ni2+and Co2+with incomplete d subshells yields the barely fluorescentand completely nonfluorescent MOFs TABD-MOF-2and TABD-MOF-3, respectively.These three TABD-MOFs with different inherent emissions were further used for selectivesensing of5MR-EHCs, the detection of which is ever urgent but has not been realized by afluorescent approach.Remarkably, the cobalt-based MOF can selectively sense the powerfulexplosive5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one (NTO) with high sensitivitydiscernible by the naked eye (detection limit=6.5ng on a1cm2testing strip) and parts perbillion-scale sensitivity by spectroscopy via pronounced fluorescence emission.