Conjugated Organic Fluorescence Molecules With Different Luminescent Colors: Preparation And Investigation On Their Force-responsive Fluorescence Properties

Currently reported luminescent materials mainly exist in the form of aggregates,thin films and solid states.When the luminescent material is used to detect toxic substances in water samples,it often appears in the form of aggregation,and when the luminescent material exists in the form of a thin film,it can be used to prepare organic light-emitting diodes and so on.In 1954,aggregation-induced fluorescence quenching(ACQ)was first reported.In the following decades,almost all luminescent materials have ACQ effect.Because they are applied in the form of aggregates,the development of luminescent materials is largely limited.Fortunately,in 2001,Academician Benzhong Tang and his team discovered the phenomenon of aggregation-induced emission(AIE).Therefore,the application constraints of traditional luminescent materials have been effectively solved,and more and more AIE luminescent materials have come one after another,and the corresponding development demands are also higher and higher.The application of AIE materials includes many fields,such as:chemical sensing,biomedical imaging and medical diagnosis,data storage and so on.With the advancement of the new era,new intelligent responsive materials have attracted extensive attention and active exploration of a large number of outstanding scientific researchers.One such smart material is a mechanochromic luminophore(MC)that responds to mechanical stimuli(such as squeezing,grinding,pulverizing,or rubbing)to change its luminous intensity or color.The design of this type of luminous body has aroused the interest of scientific researchers,because it can be applied to the fields of repeated erasing and writing materials,fingerprint anticounterfeiting,bionic skin discoloration,etc.,and it has certain research significance.Therefore,a series of fluorescent molecules with AIE emission and mechanochromic properties were designed and synthesized in this thesis.The following is a brief introduction to this paper:1.Seven phenothiazine derivatives i-1(AEPPEO)-i-7(AOPPEO)with different chain lengths were successfully designed and prepared.Studies have shown that these seven substances have aggregation-induced luminescence enhancement properties,and also show reversible mechanochromic properties of fluorescence from orange-red emission to orange light emission.This work has certain theoretical guidance for the synthesis and preparation of red light-emitting and mechanochromic AIE small molecule fluorescent materials.2.Six compounds ii-1(HMTC)-ii-6(HHCB)with different substituents based on N-hexyl carbazole units were successfully synthesized.And their mechanochromic properties were studied,and it was found that changing the substituents and then regulating the intramolecular charge transfer would affect the luminescence color of these substances and the fluorescence color after mechanical grinding.3.Three pentacene based compounds iii-1,iii-2,iii-3,with different substituents such as tetraphenylene,triphenylamine,N-phenylcarbazole,were designed and synthesized.The experimental results show that: BTPMD,PDMTD have AIE properties.BCPMD does not possess aggregation-induced luminescence properties.This study provides some valuable reference for the design and synthesis of highcontrast mechanochromic emitters.