A molecular mechanics and semiempirical molecular orbital study on the conformation of polynorbornene chains |
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| Authors: | Email author" target="_blank">Sevil?Sava?kan?Y?lmazEmail author Rza?Abbaso?lu Baki?Hazer |
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| Institution: | (1) Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey;(2) Department of Chemistry, Zonguldak Karaelmas University, 67100 Zonguldak, Turkey;(3) Food Science and Technologies Research Institute, Tübitak-Marmara Research Center, P.O. Box 21, 41470 Gebze, Kocaeli, Turkey |
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| Abstract: | The conformational analysis of polynorbornene (PNB) chains was investigated with the AM1, MM2, AMBER and OPLS methods taking into consideration the possibility of binding of norbornene monomers to each other at various positions, i.e. exo–exo, exo–endo, endo–endo. The chain that is formed by connecting exo–endo positions of the monomers has lower torsional barrier energy than those formed with bonds at other positions and has more flexibility. It is determined that the thredisyndiotactic chain formed by exo–endo addition adopts a helix structure and has a coil shape. The disyndiotactic chain formed by connecting norbornene monomers in mixed type has a linear structure. It is found that the repeat unit conformations of thredisyndiotactic and disyndiotactic chains of PNB are TGTG– and (TGTG–)2, respectively. |
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| Keywords: | PNB Semiempirical and molecular mechanics methods Conformational analysis |
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