Preparation And Fluorescence Properties Of Phosphonate Containing Siloxane

Since the 21th century,compounds with aggregation-induced emission properties have been widely used in biomedicine.With the deepening of research,the phenomenon of aggregation-induced emission of atypical chromophores(such as amines,nitriles,carbonyls,hydroxyl groups)has attracted the attention of scientists.The group containing P=O bond is also one of the atypical luminescent groups,but whether it has aggregation-induced emission properties has not been reported.In this paper,the aggregation-induced emission distinctions of compounds containing P=O bond were tested in detail.These compounds use siloxane with good molecular chain flexibility as the molecular skeleton,phosphonate group as the group containing P=O bond,and the introduction of P=O bond adjacent groups with different steric hindrances to regulate the aggregation-induced emission properties of P=O bond groups.It was found that the synthesized phosphonate-containing siloxanes exhibited remarkable aggregation-induced emission.Some phosphonate-containing siloxane molecules also exhibit up-conversion luminescence,and the up-conversion luminescence has the characteristics of aggregation-induced emission.The details are as follows:(1)Three aminopropyl siloxanes were prepared by alcoholysis followed by hydrolysis,namely aminopropyl-tri-(trimethylsiloxane)siloxane(ATTS),amino propyl-methyl-bis-(trimethylsiloxane)siloxane(AMTS)and aminopropyl-dimethyl-(trimethylsiloxane)siloxane(ADTS).A variety of tests were used to characterize the reaction and optimize the synthesis process,which improved the yield of the reaction.It provides raw materials for the subsequent preparation of phosphonate-containing siloxane.(2)Nine phosphonate-containing siloxanes were successfully synthesized by Kabachnik-Fields(KF)reaction.Namely N-(1-phosphonate diethyl-isopropyl)-?-aminopropyl-tri methylsiloxane(BITS),N-(1-phosphonate diethyl-cyclopentyl)-?-aminopropyl trimethylsiloxane(PPTS),N-(1-phosphonate diethyl-cyclohexyl)-y-aminopropyl tri(trimethylsiloxane)silane(PHTS),N-(1-phosphonate diethyl-isopropyl)-?-aminopropyl-methyl-bis(trimethylsiloxane)siloxane(BIMS),N-(1-phosphonate diethyl-cyclopentyl)-y-aminopropyl methyl bis(trimethylsiloxane)siloxane(PPDS),N-(1-phosphonate diethyl-cyclohexyl)-y-aminopropyl methyl bis-(trimethylsiloxane)siloxane(PHDS),N-(1-phosphonate diethyl-isopropyl)-y-amino-propyl-dimethyl(trimethylsiloxane)siloxane(BIDS),1,3-bis {3-[N-(1-phosphonate diethyl-cyclopentyl)]amino propyl}-1,1,3,3-tetramethyl disiloxane(DPPT),1,3-bis{3-[N-(1-phosphonate diethyl-cyclohexyl)]aminopropyl}-1,1,3,3-tetramethyl disilo xane(DHPT),and characterized by 1H-NMR,29Si-NMR,31P-NMR,mass spe-ctrometry,etc.The synthesis process was optimized to improve the yield.(3)The fluorescence properties of nine phosphonate-containing siloxanes synthesized above were tested.The fluorescence properties of nine phosphonate-containing siloxanes in methanol at different concentrations and the fluorescence properties of nine phosphonate-containing siloxanes in methanol/water mixed solutions at different proportions were tested.It was found that the nine phosphonate-containing siloxanes had different aggregation-induced emission properties.BITS,BIMS and BIDS are three phosphonate-containing siloxanes.Besides the conventional aggregation-induced luminescence,there are interesting upconversion luminescence phenomena,and the upconversion luminescence phenomena also have the characteristics of aggregation-induced emission.(4)The mechanism of aggregation-induced emission of nine phosphonate-containing siloxanes synthesized above was explored.By comparing the fluorescence properties of N-(1-phosphonate diethyl-isopropyl)-aminopropane(PIA)and Decyl phosphonate diethyl ester(DDP)without Si-O-Si bond,it is inferred that the fluorescent groups of these nine phosphonate-containing siloxanes are phosphonates.The fluorescence properties of nine phosphonate-containing siloxanes in methanol/glycerol mixed solutions with different proportions were tested and the theoretical calculations of BIMS,PPDS and PHDS were simulated.It was considered that the aggregation-induced emission mechanism of nine phosphonate-containing siloxanes included the mechanism of intramolecular motion restriction and the mechanism of intramolecular charge transfer.