ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Optically active isotactic polychloral was prepared in which the optical activity comes exclusively from molecular asymmetry (i.e., helical conformation). Molecular asymmetry requires a high conformational energy barrier for the polymer backbone, and an asymmetric initiator to induce a predominance of one helical screw-sense. Polychloral meets the criteria. Asymmetric initiators used to obtain optically active polychloral include tetramethyl ammonium (+)- or (-)-0-acetylmandelate, tetramethylammonium (+)- or (-)-0-methylmandelate, the lithiumalkoxides of methyl (+)- or (-)-mandelate, lithium cholesten-3β-oxide, lithium cholestan-3β-oxide, and lithium (+)- or (-)-2-octanoxide. Using the above initiators at 0.5 mol %, a maximum specific rotation of [α] D25 = 5000 was obtained for polychloral. Errors in specific rotation were typically ±7%.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1985.020131985102
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