Ring-opening metathesis polymerization(ROMP) of norbornene macromonomer using Mo(CHCMe_2Ph)(NAr)(OR)_2 as the initiator

摘要

Efficient polymerization of norbornene macromonomer bearing a ring-opened poly(norbornene) substituent has been accomplished by the ring-opening metathesis polymerization by the well-defined Schrock-type molbdenum initiator, Mo(CHCMe_2Ph)(N-2,6-~iPr_2C_6H_3)(OCMe(CF_3)_2).The key steps for the macromonomer synthesis are:(i) selective and capping of ring-opened poly(norbornene)with p-Me_3SiOC_6H_4CHO;(ii) exclusive hydrolysis of the SiMe_3 group;and (iii) esterification of OH group produced at the end of preformed polymer chain with norbornene carboxylic acid chloride. Mo(CHCMe_2Ph)(N-2,6-~iPr_2C_6H_3)(OCMe(CF_3)_2) was found to be an effective initiator in order for this polymerization to proceed to the complete conversion.