Synthesis Of Porous Organic Molecular Cage And Study On Its Gas Adsorption And Desorption Properties

Modified atmosphere packaging has been widely used in the shelf life extension of fresh food because of its easy handle,economic and safe properities.However,due to the abundant nutritent compounds in fresh food,it is easy to be affected by microorganism,oxygen,and carbon dioxide.Therefore,it is important to control the atmosphere condition of food package.Nowadays,porous nanomaterials have been attracted more and more attention in the controllable gas release application due to their cavities and specific porosity.In this thesis,imine cage molecule based-porous nanomaterials have been designed,prepared and characterisized,subsequently,the pore size,porosity and vacancy as well as their gas adsorption abilities have been determined as assessed.The main contents and results are as follows:?1?1-bromo-4-iodobenzene and 4-formylbenzeneboronic acid were used as starting materials to prepare 4-bromobiphenyl-4-carbaldehyde via Suzuki coupling reaction.The resulting compound then was reacted with neopentyl glycol respectively.After a series of reactions including aldol condensation and addition,hydrolysis,two monomers of dialdehyde and trialdehyde are obtained,respectively.After that,the trialdehyde is self-assembled with?1R,2R?-?-?-1,2-Diaminocyclohexane to give the imine cage molecule Cage 1,while dialdehyde and tris?2-aminoethyl?amine are self-assembled to give Cage 2.Their structures were determined by nuclear magnetic resonance?NMR?,fourier transform infrared spectroscopy?FT-IR?,ultraviolet-visible?UV-vis?spectroscopy.?2?The acid and base controllable gas release and adsorption abilities of Cage 1and Cage 2 were further investigated.The results indicated that Cage 1 and Cage 2possessed controllable gas release and adsorption abilities.Cage 1 and Cage 2 were found to decompose under acid condition,while after the addition of triethylamine,Cage 1 and Cage 2 were reformed,respectively.Cage 1 had the strongest fluorescence intensity at 612 nm.After the addition of trifluoroacetic acid,the strongest fluorescence intensity shifted to 616 nm,after the addition of triethylamine,the strongest fluorescence intensity returned to 612 nm.After addition of trifluoroacetic acid,the absorption peak of Cage 2 ultraviolet shifted from 320 nm to300 nm.While the strongest fluorescence intensity appeared at 601 nm under acid condition,and shifted to 594 nm after the addition of triethylamine.In summary,under acidic conditions,cage will decompose into substrate materials,and the original structure can be restored after the addition of alkali.?3?Brunauer-Emmett-Teller?BET?was used to determine the cavity diameter,porosity and pore volume of Cage 1 and Cage 2.The experimental results showed that the CO₂ and O₂ adsorption capacities of Cage 1 were 7.7804 cm³/g and 5.6992cm³/g at 298 K and 0.1 MPa,respectively.While the CO₂ and O₂ adsorption capacity of Cage 2 were 11.6658 cm³/g and 6.5088 cm³/g at 298 K and 0.1 MPa,respectively.?4?A novel naphthalene diimide-containing metallacycle self-assembly was prepared and was utilized to construct a novel supramolecular polymer by?-?stacking interactions.Due to the presence of the metallacycle,this supramolecular polymer is porous and has good temperature responsiveness and good photophysical properties.The reversible transformation of this supramolecular polymer between the solution phase and the gel was well controlled by changing temperature.Moreover,as shown in the TEM images,very ordered nanowires were fabricated by using perylene as a bridge to enhancing the?-?stacking interaction.The presented good controllability of this supramolecular polymer endows it good application potential in the fields of smart materials,foods,and biology.