Design, Synthesis And Application Of Novel Organic Light-emitting Systems And Photocrosslinking Bioprobes

Functional fluorescent molecules are widely used in the field of luminescent materials and biological probes,therefore,the design and synthesis of new functional fluorescent molecules become one of the hot spots in the field of chemistry.This thesis will focus on the following two aspects:1.Organic solid fluorophores,with an emission across the whole visible spectrum,have received much attention owing to theirextensive application in the fabrication of organic light-emitting diodes(OLED),optical devices,organic luminescent displays and fluorophore sensors.However,traditional organic fluorophores are usually weakly emissive or even non-emissive in the solid state,which is attributed to inherent strong intermolecular ?-? stacking interactions that consume the excitation energy.Averting this thorny aggregation-caused quenching(ACQ)process is the key to obtaining organic solid fluorophores with superior optical properties.Aggregation-induced emission(AIE)process has provided new insight for the construction of organic solid fluorophores with immunity to the ACQ process.To date,extensive technological applications have been developed.In this thesis,we will design and synthesis a new system with a tunable emission color that are based on a simple core backbone.The main contents are summarized as follows:firstly,by decorating p-bis(2,2-dicyanovinyl)benzenebased fluorophores with different types of donors(non-aromatic and aromatic substituents),We obtained two series of organic fluorophores with a tunable emission color.Secondly,the photophysical properties of the compounds were measured.The crystal packing indicated that:non-aromatic compound adopted a near planar conformation,encounters strong intermolecular ?-? stacking interactions and thus weakening the fluorescence in the solid state.The employment of aromatic groups resulted in a twisted molecular conformation.Such a contorted conformation is beneficial for the inhibition of detrimental ?-? stacking interactions and accounts for remarkable AIE features with high emission efficiency in the solid state.2.Photoactivable reagents have been widely used as a photo crossing reactions.Because these reagents are inert under normal conditions and become activated upon UV irradiation,they offer a unique advantage of allowing temporal and spatial control over reactivity.The most commonly used photoactivable groups include aryl ketones,aryl azides,and diazirines,which generally require photoirradiation then undergo rapid reactions with surrounding biomolecules to form the cross-linked photoadducts.Since the development of the new tetrazole-alkene 1,3-dipolar cycloaddition reaction from the Lin group,a large number of applications have been reported for labeling biomolecules.However,it is highly desirable that this photoactivation takes place at longer-wavelength irradiation to minimum photodamage to the living cells.In this thesis,we design and synthesis a series of long-wavelength photoactivable reagents.The main contents are summarized as follows:firstly,by adjusting the electron properties of substituents on the N-phenyl or C-phenyl ring,we have obtained several long-wavelength photoactivable tetrazoles that showed excellent reactivity toward alkenes using a hand-held UV lamp at 365nm.Secondly,the reaction kinetics based on the HPLC traces was measured and the corresponding reaction can be completed in about lmin.Therefore,this long-wavelength photoactivable reagent is expected to be applied to cell labeling in vivo.