| Room temperature phosphorescence（RTP）materials have attracted scientists’attention due to their long lifetime and large Stokes shift.Compared with inorganic or metal-organic phosphorescent materials,pure organic ones have the advantages of low cost,low toxicity and structural diversity,which makes them show great potential in the applications of biological imaging,optical display,sensing,anti-counterfeiting and gas detection.In this thesis,a series of pure organic room temperature phosphorescent materials and functionalized mechanoluminescent materials were designed and synthesized based on phenothiazine derivatives.The details are as follows:Chapter 1:The basic principles of luminescence and related concepts of organic room temperature phosphorescence are first introduced,and then some effective strategies for enhancing organic room temperature phosphorescence are summarized.Finally,the structural characteristics of phenothiazine derivatives and the corresponding research progress in the field of photoelectronics are briefly summarized.Chapter 2:Three kinds of pure organic room temperature phosphorescent materials with stimulus response by integrating phenothiazine and pyridine group together,Cz S-o-py,Cz S-m-py and Cz S-p-py,were designed and synthesized.Their organic room-temperature phosphorescence（RTP）properties could be adjusted via orderly stimulus-responsive molecular motion in the crystal.Careful analyses of the single-crystal structure before and after ordered molecular motion,coupled with theoretical calculations,reveals the effective intermolecular charge transfer generated by the dense packing mode to be responsible for the RTP effect.Accordingly,a dual anti-counterfeiting application is successfully implemented,exploiting the RTP effect with stimulus response.The introduction of molecular mechanical technology may provide a strategy for the molecular design,internal mechanism exploration,and practical application of RTP luminescent agents.Chapter 3:A phenothiazine derivative Ptz Chol containing non-conjugated chiral cholesterol group was designed and synthesized.By analyzing the single crystal structure of Ptz Chol carefully,coupled with the circular dichroism（CD）signals before and after grinding,it was found that the introduction of cholesterol led to the production of chiral space group for Ptz Chol crystal,then contributing much to the mechanoluminescence（ML）androom temperature phosphorescence（RTP）effect.Throughout the entirelight-emitting process,the CD signal could well reflect the changes of molecular arrangement.Chapter 4:We developed a new host-guest doping system with stimulus-responsive RTP characteristics,in which triphenylphosphine oxide（OPph3）acted as host and（di）benzophenothiazine dioxide derivatives as guests.Turn-on RTP effect was realized by mixing them together through co-crystallization or grinding,in which the efficient energy transfer from host to guest and the strong intersystem crossing（ISC）ability of the guest have played significant role.Further on,multistage stimulus-responsive RTP characteristics from grinding to chemical stimulus were achieved via introducing pyridine group into the guest molecule.In addition,the anticounterfeiting printings were realized for these materials through various methods,including stylus printing,thermal printing and inkjet printing,which brings RTP materials closer to commercialization.Chapter 5:The relationship between the electronic effect of substituents and thermodynamically stable conformation in phenothiazine derivatives is discussed for the first time.When the substituent is phenyl or 3-position pyridyl group,the quasi-equatorial（QE）conformation is the main thermo-stable conformation.At this time,the lone pair electrons of the 10-position nitrogen are stabilized by the benzene or naphthalene ring in the core,forming a large p-πconjugated electron system.When the substituent is 2-pyridine or 4-pyridine groups,the lone pair electrons are more easily stabilized by the electron-deficientπsystem,and another thermo-stable p-πconjugated conformation,namely quasi-axial（QA）conformation,is formed.In addition,the effects of the two conformations on the singlet and triplet energy levels are studied in detail.Experimental results and theoretical calculations show that the QE conformation has a lower energy level than the QA one.Finally,one molecule containing two conformations was combined with 3D printing and successfully applied to advanced anti-counterfeiting having time-resolve color change.Chapter 6:We designed and synthesized two pure organic compounds of PBO and PBS through integrating planar dibenzothiophene/dibenzofuran and two phenothiazine groups together with twisted C-N bonds,which form organic microporous crystals with very good stability against strong acids and bases via pure C-H…πinteractions.Accordingly,the effective absorption of toluene has been successfully realized with an adsorbing capacity of 6.20 mmol g-1,regardless of the interference of water vapor.Excitingly,these microporous materials exhibit interesting crystal-to-crystal transformation（CCT）property accompanied by changed pore size on being exposed to different organic vapors.Therefore,the desorption process of toluene could be completed through a simple exposure to dichloromethane（DCM）vapor and the second transformation of the crystal occurred in this process. |
PDF Full Text Request