Synthesis And Applications Of Pillar[5]Arene And Platinum Metallacycle

Macrocyclic molecules are an important part of supramolecular chemistry.Among them,pillararenes and metal macrocyclic compounds are important components of macrocyclic molecules.Due to their good host-guest properties,the development of functionalized host-guest compounds and the construction of various new materials are hot research fields in recent years.In this paper,pillar[5]arene-based Schiff base and organic platinum metal macrocycles were designed and synthesized to assemble pH-responsive supramolecular nanomaterials to study their application in cell imaging and cancer treatment.Based on the host-guest molecular recognition and metal ion coordination of pillar[5]arene,a fluorescent supramolecular polymer was constructed to study its application in catalytic reduction of nitrophenol compounds.Details are as follows:1.Cocktail therapy is one of the leading approaches for treating some complex diseases.Herein,a pH-triggered supramolecular cocktail drug delivery system assembled by the medium-strength complexes of pillar[5]arene-based schiff base(P5SB)with methylene blue(MB).Molecular modeling suggest that noncovalent interactions between Schiff base side chain of P5SB and MB were mainly responsible for the stability of the complex.The amphiphilic P5SB?MB complex assembled into stable vesicles with an average diameter of 244.1 nm in conventional physiological environment(pH=7.4).Under the irradiation of 660 nm laser,singlet oxygen was produced to inhibit the growth of tumor cells,while the quantum yield of P5SB?MB was higher compared with that of MB(ΦΔMB=0.5).So,the P5SB?MB complex could improve the efficiency of photodynamic therapy.Drug loading experiments demonstrated that doxorubicin(DOX)could be efficiently encapsulated into the hollow vesicles,and the drug would be rapidly released under acidic environment(pH=6.0).Moreover,the anti-cancer efficiency of DOX-loaded P5SB?MB vesicles was significantly enhanced because of the synergistic effect of P5SB,MB and DOX.Nonetheless,the live-cell imaging property of DOX was maintained after encapsulation2.Photosynthesis is the process by which living plants use photosynthetic pigments,such as chlorophyll,to convert CO2 and water into organics and release O2 under visible light.In this work,a fluorescent supramolecular polymer(P5Py2/Zn/Gen)n has been successfully constructed based on orthogonal pillar[5]arene-based molecular recognition and metal ion coordination to mimic this process.In the supramolecular polymer,the Gen unit can be acted as a light-harvesting moiety due to ACQ effect was inhibited by host-guest interaction whereas the(Py)2/Zn center can be acted as a catalytic site.Such orthogonal self-assembly strategy enhanced the stability of both donor and acceptor in catalyzing reduction of p-nitrophenol to p-aminophenol and endowed this photocatalyst can be reused at least 5 times with significant conversion lost.This study provides us a pathway to construct a recycle artificial light-harvesting system to mimic the entire process of photosynthesis3.Metal macrocycles were synthesized by para-pyridine porphyrins with organic platinum,and then self-assembled with the amphiphilic guest TPE-PEG to form nanoparticles(NPs)TPE-PEG@1.Similarly,para-pyridine porphyrins self-assembled with the amphiphilic guest TPE-PEG to form nanoparticles TPE-PEG@2,and the morphology of the NPs was characterized by TEM and SEM.The detection experiments of singlet oxygen showed that both nanoparticles could produce singlet oxygen under the irradiation of 660 nm laser,but TPE-PEG@1 had a stronger ability to produce it.MTT assay and particle size analysis showed that under low pH conditions,the nanoparticles were damaged and TPE-PEG@1 was able to release platinum drugs,which had stronger tumor killing power compared to TPE-PEG@2.The synergistic treatment of chemotherapy and photodynamic therapy significantly improved the anti-tumor properties.TPE-PEG had strong fluorescence and was able to perform cell imaging in cells.The integration of chemotherapy,photodynamic therapy and imaging provides new ideas for the development of supramolecular materials.