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An Efficient Ring‐Closure Method for Preparing Well‐Defined Cyclic Polynorbornenes
Author(s) -
Zhang Minghui,
Wu Ying,
Liu Zhengping,
Li Jun,
Huang Liyan,
Zhang Ke
Publication year - 2020
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201900598
Subject(s) - romp , azide , metathesis , chemistry , ring (chemistry) , cycloaddition , click chemistry , polymer chemistry , ring opening metathesis polymerisation , polymerization , polymer , organic chemistry , catalysis
An efficient bimolecular ring‐closure method is developed to prepare the well‐defined cyclic polynorbornenes by combining the living ring‐opening metathesis polymerization (ROMP) with the self‐accelerating double strain‐promoted azide–alkyne cycloaddition (DSPAAC) reaction. In this method, ROMP is used to synthesize the well‐defined linear polynorbornenes with both azide terminals by virtue of a N ‐hydroxysuccinimide‐ester‐functionalized Grubbs initiator following the modification of polymer end groups. DSPAAC click reaction is then used to ring‐close the linear polymer precursors and prepare the corresponding well‐defined cyclic polynorbornenes using the sym‐dibenzo‐1,5‐cyclooctadiene‐3,7‐diyne (DIBOD) as small linkers. The self‐accelerating DSPAAC ring‐closing reaction facilitates this method to efficiently prepare pure cyclic polynorbornenes in the presence of a molar excess of DIBOD small linkers to the linear polynorbornene precursors. This is the first report to prepare well‐defined polynorbornenes with cyclic topology based on the ring‐closure strategy for cyclic polymers.