Construction And Performance Studies Of The Two-Dimensional Supramolecular Organic Frameworks Based On Host-Guest Interactions

Supramolecular self-assembly,which focuses on the structure and function of aggregates formed by non-covalent interactions,as well as the process and regulation of the formation of the aggregates,has attracted extensive research interests.As a kind of molecular assembly with precise structure,supramolecular organic framework（SOF）has been widely reported in recent years due to its homogeneous water solubility,periodic porous structure and ease of synthesis and modification.In addition,the applications of SOF in ion and explosive detection,drug delivery,visible-light-driven hydrogen evolution and photodynamic therapy have also been reported,which greatly enriching the application examples of SOF and showing the great significance of SOF.The paper herein mainly includes the following three parts of work:1.The tetraphenylethylene derivative 1 substituted by four methyl viologen units and oligoethylene glycol derivatives 2 and 3 substituted by two methoxy naphthyl units were designed and synthesized.The methyl viologen units of compound 1 and the methoxy naphthalene units of compounds 2 and 3 can be encapsulated by the cavity of CB[8]to form two novel two-dimensional SOF（SOF-1 and SOF-2）through the encapsulation enhanced donor-receptor interaction.SOF-1 and SOF-2 have good water solubility and fluorescence emission at 350 nm-500 nm.More importantly,based on the energy transfer process,this two SOFs can achieve the specific detection of CrO₄^2-,Cr₂O₇^2-and MnO₄^-in aqueous solution and show excellent detection abilities.The detection limits of SOF-1 for CrO₄^2-,Cr₂O₇^2-and MnO₄^-are calculated to be 1.88×10^-4 M,1.59×10^-4 M and 1.98×10^-4 M,respectively.And the detection limits of SOF-2 for CrO₄^2-,Cr₂O₇^2-and MnO₄^-are calculated to be 1.79×10^-4 M,2.22×10^-4 M and 1.98×10^-4 M,respectively.This work provides a new idea for the construction and application of SOF in aqueous solution.2.The tetraphenylethylene derivative MV-TPE modified by four methyl viologen units and the tetraphenylethylene derivative NA-TPE modified by four methoxy naphthalene units were designed and synthesized.A novel two-dimensional SOF was further constructed in aqueous solution through the encapsulation enhanced donor-receptor interaction between MV-TPE,NA-TPE and CB[8].The obtained SOF shows the bright cyan emission at 489 nm in aqueous solution and can be further employed as an energy donor for the construction of artificial LHS.By introducing the energy acceptor 4,7-bis（2-thiophenyl）-2,1,3-benzothiadiazole（DBT）into the aqueous solution of SOF,an efficient energy transfer process from SOF to DBT can be realized.When SOF:DBT=100:1,the energy transfer efficiency and antenna effect of the LHS are calculated to be 70.2%and12.3%,respectively.Morover,the second energy transfer process from SOF+DBT to SR101 can also be realized after introducing the second energy receptor amphoteric sulforhodamine 101（SR101）into the SOF+DBT system.When SOF:DBT:SR101=100:1:3,the second step energy transfer efficiency and antenna effect of the system are calculated to be 44.5%and 1.8,respectively.In addition,we also realized the white light emission of the system through the energy transfer process between SOF and SR101.When SOF:SR101=100:8,the CIE coordinate of the system is（0.31,0.32）,which is close to the CIE coordinate of standard white light emission（0.33,0.33）.Finally,in order to make full use of the harvested energy,we attempt to employ the obtained artificial LHS to catalyze the aerobic cross coupling dehydrogenation（CDC）reaction in aqueous solution.To our delight,SOF+DBT+SR101 system showed excellent catalytic ability for CDC reaction.When 0.45 mol%SOF+DBT+SR101 system were added,the yield of model reaction reached 83%.Moreover,the system also showed good catalytic effect on a variety of substrates.This work provides a new strategy for the construction and application of SOF and artificial LHS in aqueous solution.3.The pyrene derivative（Pmvp）modified by four methylated vinylpyridine units was designed and synthesized.A novel two-dimensional SOF was further constructed in aqueous solution based on the host-guest interaction between Pmvp and CB[8].The methylated vinylpyridine arms of Pmvp can be encapsulated by the cavity of CB[8]in the form of head-to-tail.Moreover,this pyrene-based SOF shows good ability to generate reactive oxygen species（¹O₂andO₂）.Therefore,the SOF herein can be used directly to promot the photocatalytic reaction of thioanisole in aqueous solutions.In the presence of1.0 mol%SOF,the yield of the photooxidation reaction of thioanisole can reach 87%.In addition,this pyrene-based SOF also shows excellent catalytic effect on a variety of thioanisole derivatives.This work provides a new strategy and direction for the construction and application of SOFs.