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The structure of the poly(vinyl chloride) chain. I. Conformation of 2,4‐dichloropentane
Author(s) -
Burda J.,
Lukáš R.
Publication year - 1989
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19890290126
Subject(s) - mndo , conformational isomerism , carbon chain , vinyl chloride , chemistry , tacticity , chain (unit) , asymmetric carbon , cndo/2 , quantum chemical , carbon fibers , crystallography , computational chemistry , molecule , materials science , polymer , organic chemistry , copolymer , physics , polymerization , optically active , astronomy , composite number , composite material
Using semiempirical quantum chemical CNDO/2 and MNDO methods, hindered rotations of the carbon chain of 2,4‐dichloropentane stereoisomers were studied. The results obtained confirm the experimental finding that the most important structures of the racemic and meso form of 2,4‐dichloropentane are TT‐racemo (TT‐syndio), GG‐racemo (GG‐syndio) and TG‐meso (TG‐iso) conformers. A more detailed analysis of non‐bonding interactions showed, however, that the energetically most advantageous structures are the partly geometrically shifted TT‐syndio and TG‐iso conformers. In the case of the TT‐syndio conformation MNDO predicts a rotation of the carbon chain by 13.254°, which for the poly(vinyl chloride) chain explains the helical structure of syndiotactic sequences.