Self-Accelerating Click Reaction in Step Polymerization

Abstract

A self-accelerating double-strain-promoted azide−alkyne cycloaddition reaction (DSPAAC) was used in the step polymerization for the first time. This produced a novel stoichiometric imbalance-promoted homogeneous step polymerization method using sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DIBOD) and various bis-azide compounds (N 3 -R-N 3 ) as respective monomers. Because of the self-accelerating property of DSPAAC reaction, the novel step polymerization method could prepare high molecular weight polymers under stoichiometry imbalance condition with excess molar amounts of DIBOD to N 3 -R-N 3 . Based on the click property of DSPAAC reaction, the novel step polymerization could be efficiently performed in very mild reaction conditions such as in air at room temperature without requiring any metal catalyst or chemical stimulus. Under the present polymerization condition, the preparation of high molecular weight polymers from this novel method was accompanied by the formation of cyclic oligomers with a weight content above 30%. The resultant polymers possessed a unique fluorescence property, which emitted strong fluorescence peaking at 412 nm under UV irradiation at 280 nm.

Hyperbranched Multicyclic Polymer Built from Tailored Multifunctional Monocyclic Prepolymer

“…To construct hyperbranched multicyclic polymer, selecting a proper A 2 monomer is of great importance in order to achieve a high molecular weight. In recent years, Zhang et al reported self‐accelerating double‐strain‐promoted azide−alkyne cycloaddition reaction (DSPAAC) to prepare cyclic polymers and periodic polymers . In this reaction, a commercially available chemical, sym ‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne (DBA) was used, and it revealed an interesting chemical property, that is, once the cycloaddition of the first alkyne of DBA with azide occurred, the reactivity of the second alkyne would be enhanced significantly due to the increased ring strain of DBA.…”

“…In this reaction, a commercially available chemical, sym ‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne (DBA) was used, and it revealed an interesting chemical property, that is, once the cycloaddition of the first alkyne of DBA with azide occurred, the reactivity of the second alkyne would be enhanced significantly due to the increased ring strain of DBA. When this type of A 2 monomer is used in polycondensation, a high molecular weight of the resultant polymer can be realized even in a stoichiometric imbalance condition . Thus, the polymerization of DBA and c‐PS was conducted in THF, and the detailed reaction condition is given in Supporting Information.…”

“…In recent years, Zhang et al reported selfaccelerating doublestrainpromoted azide−alkyne cycloaddition reac tion (DSPAAC) to prepare cyclic polymers and periodic poly mers. [38][39][40] In this reaction, a commercially available chemical, symdibenzo1,5cyclooctadiene3,7diyne (DBA) was used, and it revealed an interesting chemical property, that is, once the cycloaddition of the first alkyne of DBA with azide occurred, the reactivity of the second alkyne would be enhanced signifi cantly due to the increased ring strain of DBA. When this type of A 2 mono mer is used in polycondensation, a high molecular weight of the resultant polymer can be realized even in a stoi chiometric imbalance condition.…”

“…When this type of A 2 mono mer is used in polycondensation, a high molecular weight of the resultant polymer can be realized even in a stoi chiometric imbalance condition. [38] Thus, the polymerization of DBA and cPS was conducted in THF, and the detailed reac tion condition is given in Supporting Information. Figure 4a shows GPC curve (black solid line) of the obtained hyper branched multicyclic poly styrene (hcPS), which reveals that the molecular weight increases obviously after reacting for 12 h, and exhibits a characteristic multimodal peak of hyper branched polymer.…”

Strain‐Promoted Double Azide Addition to Octadehydrodibenzo[12]annulene Derivatives

“…[20][21][22][23][24][25][26][27][28] This feature was successfully applied to the synthesis of cyclic polymers and stepgrowth polymerization. [29,30] However, due to the very fast reaction, the regiochemistry of the bis-triazole products (2a and 2b) was not totally controlled.…”