Accession Number : ADA295717

Title :   Exploring Factors that Determine Cis/Trans Structure and Tacticity in Polymers Prepared by Ring Opening Metathesis Polymerizations Involving Initiators of the Type Syn and Anti Mo(NAr)(CHCMe2Ph)(OR)2. Observation of a Temperature Dependent Cis/Trans Ratio.

Descriptive Note : Tecnical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY

Personal Author(s) : Schrock, Richard R. ; Lee, Jin-Kyu ; O'Dell, Richard ; Oskam, John H.

PDF Url : ADA295717

Report Date : 14 JUN 1995

Pagination or Media Count : 30

Abstract : The factors that determine the structure (cis/trans and tacticity) of polymers prepared by ring opening metathesis polymerization (ROMP) Using well-defined initiators of the type Mo(NAryl)(CHCMe2Ph)(OR)2 (Aryl = a substituted aryl group and OR = a variety of alkoxides) have been explored. The main finding is a dependence of cis/trans structure on temperature; at low temperatures (-35 deg C) all cis polymer is formed and at high temperatures (65 deg C) up to 90% trans polymers are formed. These results are consistent with formation of cis polymer from syn alkylidene rotamers and trans polymer from anti alkylidene rotamers in circumstances where syn and anti rotamers can interconvert. jg

Descriptors :   *POLYMERS, LOW TEMPERATURE, OPENING(PROCESS), METHYL RADICALS, HIGH TEMPERATURE, POLYMERIZATION, MOLYBDENUM, HYDROGEN, CHEMICAL REACTIONS, SYMMETRY, ARYL RADICALS, MOLECULAR STRUCTURE, SUBSTITUTES, RINGS, PHENYL RADICALS, HYDROXYL RADICALS, ALCOHOLS, ALKALI METALS, ALKOXY RADICALS.

Subject Categories : Polymer Chemistry
      Inorganic Chemistry
      Organic Chemistry
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE