Preparation And Properties Of Dynamic Room Temperature Phosphorescence Of Coordination Polymers-Based Materials

Compared with static room temperature phosphorescence（RTP）,dynamic organic ultra-long room temperature phosphorescent material is a new type of smart luminescent material,which can show reversible significant phosphorescent properties（such as intensity,life,color,etc.）changes under external stimulation.It has potential application in the fields of multi-color display,high-end anti-counterfeiting and photoelectric devices.However,it is still a challenge to realize efficient room temperature phosphorescence due to the effects of spin prohibition from singlet to triplet state,weak spin orbit coupling（SOC）and quenching of triplet state by oxygen.In recent years,the room temperature phosphorescent materials with extremely long life could be achieved by the introduction of heteroatoms,crystallization and host-guest doping.The design strategies and types of dynamic room temperature phosphorescent materials are scarce.It is urgent to explore new dynamic organic room temperature phosphorescent materials,develop new construction methods and reveal their luminescence mechanism.As a class of crystal materials,coordination polymer has a wealth of building modules,which can create the relatively rigid and ordered environment,provide precise molecular structure,increase the rigidity of phosphor molecules,inhibit their non-radiative transition.metal cluster nodes can promote spin orbit coupling,and thus increase the rate of intersystem passage,which has its own advantages in the development of room temperature phosphorescence.Based on this,this paper mainly chooses the method of coordination induction,through the introduction of chiral molecules and host-guest doping strategy,to realize the dynamic response of ultra-long room temperature phosphorescent materials,and the mechanism of in-depth study.1.Firstly,1H-1,2,3-triazole[4,5-b]pyridine（Trzpy）molecule was selected,and the photophysical properties and crystal structure of Trzpy were analyzed in detail.The molecule itself existed in the form of monomer,dimer and tetramer through intermolecular hydrogen bonding andπ-πstacking,but showed green afterglow emission.Pure chiral enantiomer compounds Zn（Trzpy）（D-ala）（DCF-10）and Zn（Trzpy）（L-ala）（LCF-10）have been synthesized by coordination of chiral molecules D/L-alanine（D/L-ala）through ligand inducted strategy.The two compounds exhibit dynamic room temperature phosphorescence properties dependent on excitation wavelength.When the excitation wavelength changes from290 nm to 440 nm,the emission color of the afterglow changes from blue-green to orange.According to the crystal structure analysis,the two compounds successfully achieved the amplification from the point chirality to the three-dimensional skeleton chirality,and thus achieved the circularly polarized luminescence of fluorescence（425 nm）and phosphorescence（550 nm）,respectively.Based on the multi-color tunable optical properties of the two coordination compounds,they have a good application prospect in the field of multi-information encryption.2.1,1,2,2-tetrad（pyridine-4-yl）ethylene（TPE）molecule acted as linkers.Firstly,two enantiomer compounds[Zn₂（D-cam）₂（TPE）]（DCF-12）and[Zn₂（L-cam）₂（TPE）]（LCF-12）were synthesized by ligand-induced strategy.These two compounds showed high porosity,high stability and excellent blue-white fluorescence emission.By using these compounds as nanocontainers,the guest luminescent molecule 2,7-dimethyl pyrene was encapsulated into the free space,and the excitation wavelength-dependent red phosphorescence emission was realized.Interestingly,the phosphorescence of the host-guest complex disappeared at room temperature after being dried,and RTP recovered immediately after being soaked in benzyl alcohol solution,achieving solvent-responsive phosphorescence.Importantly,the host-guest complexes show the high quantum yields,up to 87.73%and 89.65%.