An Organic Phosphonate Room Temperature Phosphorescent Material Constructed By Multidentate N/O Ligands

Room temperature phosphorescence?RTP?materials have great important applications in the fields of display,anti-counterfeiting,and biological imaging.To design and synthesize RTP materials,it is necessary to increase the intersystem crossing?ISC?rate and simultaneously suppress non-radiation decay.Due to the restricted molecular motion/vibration at low temperatures,most organic molecules exhibit phosphorescence at 77 K because of the depressed non-radiative decay.Therefore,it is of significance to develop new RTP materials via constructing a rigid environment to simulate cryo-conditions to effectively restrict the molecular motion/vibration of organic luminogens.Based on the coordination-driven assembly strategy,dispersing organic N/O-ligands with potential phosphorescence into metal phosphonate system to adjust their RTP performance.The anchoring effect of rigid metal phosphonate matrix on organic N/O units and its influence on RTP properties will be studied.According to the host-guest chemistry,guests with matchable charge and size will also be introduced to suitable hybrid metal phosphonate systems with the goal of further anchoring the organic luminogens based on the host-guest interactions to optimize the resultant RTP performance.The main contents of this thesis are as follows:?1?introduces the synthesis and RTP properties of hybrid metal phosphonate based on polydentate N-ligands 1,2,4,5-tetrakis?imidazole-1-methylene?benzene?TPI?.Two hybrid metal phosphonates with RTP performance,[Zn₂?HEDP??TPI?_0.5]?1?and[Zn₂?HEDP??TPI?_0.5]?2?,were prepared via introducing TPI to the metal-HEDP?1-hydroxyethylidenediphosphonate?system.Compounds 1 and 2 are supramolecular isomers.Interestingly,compounds 1 and 2 feature different RTP performances in terms of phosphorescent lifetime and quantum yield,which may be ascribed to the distinct configuration of TPI.Compared with 1,the stronger intermolecular interactions among TPI results in better RTP performance of 2.?2?Chapter 4 introduces the synthesis and RTP properties of hybrid metal phosphonates based on polydentate O-ligands.Three hybrid metal phosphonates:[A]·[Zn₂?HEDP??TPA?_0.5?H₂O?₂]·nH₂O?3:A=NH₃Me,n=2;4:A=NH₂?Me?₂,n=1;5:A=NH₂?Et?₂,n=0?,are fabricated via introducing terephthalate?TPA?into the metal-HEDP system.The coordination anchoring between zinc ions and TPA ligands,together with the electrostatic interactions between the protonated organoamine guests and TPA units,effectively hinder the vibration/rotation of the organic luminogens and suppress the nonradiative decay.Photoluminescent measurements indicated that compounds 3-5showed dark blue phosphorescence with the quantum yield of compounds 5 is 80.7%.Therefore,guest-dependent RTP performance was observed in this crystalline host-guest platform,which is further testified by theoretical calculations.Similar hybrid RTP materials?compounds 6-8?could also be produced via introducing biphenyl-4,4?-dicarboxylic acid?H₂BPDC?and 4-pyrazole carboxylic acid?H₂L?bearing similar coordination mode to TPA to metal-HEDP system.