Accession Number:

ADA272649

Title:

Polymerization of Enantiomerically Pure 2,3-Dicarboalkoxy Norbornadienes and 5,6-Disubstituted Norbornenes by Well-Characterized Molybdenum ROMP catalysts

Descriptive Note:

Technical rept. no. 22,

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY

Report Date:

1993-10-29

Pagination or Media Count:

39.0

Abstract:

Preparing polymers with a regular primary structure is a prerequisite to ultimately controlling the properties of the bulk polymer in a systematic manner. Polymers prepared by ring-opening metathesis polymerization ROMP of norbornenes and norbornadienes employing classical metathesis catalysts are rarely regular. In contrast, it has been shown that 2,3-bistrifluoromethyl norbornadiene NBDF6 and 2,3-dicarbomethoxy norbornadiene DCMNBD can be ring- opened with well-characterized catalysts of the type MoCHCMe2RNArOR2 R Me, Ph Ar 2,6-i-Pr2-C6H3 to give highly tactic 90 high trans poly NBDF6 and polyDCMNBD when OR O-t-BU, and high cis poly NBDF6 and poly DCMNBD with a tactic bias of approx. 75 sigma mc0.75 when OR OCMeCF3 2. The four possible regular structures of polymers of this type are shown in Scheme I. It has been suggested that high trans poly NBDF6 and high cis poly NBDF6 prepared using the initiators mentioned above both have a syndiotactic bias B and C, respectively on the basis of the measurement of the value of the relaxed dielectric constant

Subject Categories:

  • Physical Chemistry
  • Polymer Chemistry
  • Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE