Synthesis And Fluorescence Properties Of Cyclophosphazene Nucleophilic Substitution Products

Cyclophosphazene is a type of compound in which the main chain is alternately arranged with single and double bonds of phosphorus and nitrogen atoms,and two substituents are connected to the phosphorus atom.Hexachlorocyclotriphosphazene is the most representative compound in cyclophosphazene compounds.Such compounds can closely combine inorganic and organic molecules through nucleophilic substitution reactions,and at the same time utilize the high flexibility and flame-retardant properties of the main chain,showing superior performance unmatched by traditional compounds.In this study,a solvothermal method was proposed for the preparation of polycyclic cyclophosphazenes,and a series of compounds that could be used as fluorescent quantum probes were synthesized;in addition,phenoxy and alcoholoxy groups were introduced into the structure by nucleophilic substitution reaction,to obtain a series of phosphazene-based lubricants.The research yielded the following results:1.Take hexachlorocyclotriphosphazene and 2,2’-biphenol as raw materials,select K₂CO₃as acid binding agent,and acetone as solvent to react to obtain the key interme-diate 2,2’-biphenoloxy The precursors of cyclochlorophosphazene N₃P₃(O₂C₁₂H₈)Cl₄and N₃P₃(O₂C₁₂H₈)₂Cl₂,the yields were 91.32%and 89.73%;the subsequent nucleophilic substitution by solvothermal method gave a series of novel cyclotriphosphazene compounds in yields from 13.78-91.32%,through the optimization of the reaction,the optimized reaction conditions are obtained:using acetone as solvent,K₂CO₃as acid binding agent,react at 56 ℃ for 10 h;After the reaction,a novel cyclotriphosphazene derivative was obtained in a yield of61.10-91.32%.The intermediates and final products were characterized by ¹H NMR,¹³C NMR,IR and HRMS,and the structures of the compounds were determined.All are（2,2’-biphenoloxy）n-（ethylenediamino）m-cyclotriphosphazene structure,wherein n+m=3.The photoluminescence properties of the two types of compounds are better than those of traditional Schiff base-substituted cyclophosphazene compounds,and their abso-rption and emission spectra are more sensitive to H⁺and Cu⁺ions.A larger conjugated structure is formed,with photoluminescence properties,and at the same time,the overall stability of the compound is increased.2.Using hexachlorocyclotriphosphazene as raw material,the possibility of nucleophilic substitution of phenols and alcohols was verified by a single substituent total substitution reaction,and a series of cyclophosphazene monosubstituted products were obtained;the obtained monosubstituted products Obtained where the substitution conditions are:（1）For phenolic compounds,use toluene as dehydration solvent to prepare potassium salt,use acetonitrile as reaction solvent,and react at82℃ for 10 h;（2）For alcohol compounds,prepare sodium from metal sodium.The salt was reacted with THF as the reaction solvent at 66℃ for 10 h.The yields of the five monosubstituted compounds ranged from 79-89%,and the molecular weights were 406,729,729,778 and 1102,respectively.The structures and purities of the compounds were characterized by ³¹P NMR and HRMS.3.On the basis of the synthesis of cyclophosphazene mono-substituted products,the corresponding mixed substituted cyclotriphosphazene products were prepared by the potassium salt dehydration method and the Cs₂CO₃method,respectively.The substituent groups included trifluoroethoxy,One or more of p-methylphenoxy,m-methylphenoxy,fluorophenoxy and m-trifluoromethylphenoxy,the crude product is further processed to improve the purity and pour point characteristics,mainly using Alkaline washing,column chromatography,etc.,the molecular weight range is423-996 for purification and testing.The compounds were characterized by ¹H NMR,³¹P NMR and HRMS for structure and purity.