Covalent Organic Polymers:Synthesis And Applications To Organic Catalysis And Fluorescence Sensing

Covalent organic polymers have excellent physical and chemical properties,such as controllable structure,adjustable function,highly stability and so on.By integrating different functional molecules,they have been widely used in gas storage,adsorption,separation and catalysis,energy,sensors,biomedicine and other fields.In particular,organic porous polymers can be connected by covalent bonds through simple structural units,which has attracted the attention of researchers.In recent years,more and more porous materials have been synthesized and applied rapidly.Therefore,it is of great significance to design and synthesize new covalent organic polymers,especially porous ones,and to develop their applications.In this paper,based on solvothermal method,two covalent organic polymer materials were synthesized by Suzuki miyaara cross coupling reaction and Schiff base reaction with porphyrin and salicylaldehyde rich in heteroatom.The structure,morphology and properties of the materials were studied by infrared spectroscopy,solid-state nuclear magnetic resonance,scanning electron microscopy,transmission electron microscopy,X-ray photoelectron spectroscopy,thermogravimetry and other characterization methods,and the application of these materials in organic catalysis,sensing and other fields was preliminarily explored.The main contents of this study are as follows:1.First,two structural units of 5,10,15,20-tetra?4-bromophenyl?porphyrin and pyrene-2,7-dibasic acid bis?pinacol?ester were synthesized,and then the porphyrinyl covalent organic polymer?COP-1?was synthesized by Suzuki miyaara cross coupling reaction.Because of the strong coordination ability of porphyrin,Pd is introduced into the porphyrin ring to deposit metal in the material.In the presence of potassium carbonate,Pd-COP-1 was used to catalyze Suzuki miyaara coupling reaction.With p-bromobenzaldehyde and phenylboronic acid as substrates,98%of the reaction yield could be obtained at 60?for 6 hours under mild reaction conditions,with high catalyst stability.74%of the reaction yield could be obtained after 5 times of catalyst circulation Rate.In the presence of sodium borohydride,the k_apppp values of2-nitrophenol,3-nitrophenol and 4-nitrophenol are 1.08,1.66 and 0.60×10^-2s^-1,respectively.After five cycles of use,the catalyst still has high activity,and the reduction of 4-nitrophenol can still reach 922.Synthesis of[1,3,5-tris?5-tert-butyl-3-formyl-4-hydroxyphenyl?ethynyl]benzene monomer,with hydrazine hydrate in solvothermal conditions through Schiff base condensation method to generate covalent organic polymer?COP-2?,the material has very good fluorescence and metal chelating properties.This material has a very good detection effect for copper metal ions.When there are copper ions in the suspension,the fluorescence quenching effect can occur.In the presence of other metal cations or anions,it will not interfere with the selectivity of COP-2 to Cu²⁺.Moreover,when the strong complexing agent is added,the fluorescence intensity can be restored,which can be used for the second detection.After five cycles of use,the copper ion still has obvious quenching effect on popi1.This kind of porous material is applied in the field of metal ion detection,which expands the application range of porous material and has very important significance.