TY - JOUR
T1 - The structure of poly(di-n-propylsilylenemethylene)
AU - Park, S. Y.
AU - Interrante, L. V.
AU - Farmer, B. L.
PY - 2001
Y1 - 2001
N2 - The structure of poly(di-n-propylsilylenemethylene) (PDPrSM) has been studied by X-ray diffraction, electron diffraction and molecular modeling. The fiber X-ray data and the electron diffraction pattern of single crystals show that PDPrSM has triclinic symmetry with unit cell parameters a = 10.52 Å, b = 8.66 Å, c = 4.86 Å, α = 78.4°, β = 100.0° γ = 98.2°. The fiber repeat, 4.86 Å, indicates an all-gauche conformation in the main chain, giving a 41 helical structure. Ab initio and semi-empirical energy calculations show that with attachment of n-alkyl side chains an all-gauche conformation for the main chain gives the lowest energy. This is in contrast to the unsubstituted polymer, poly(silaethylene), which has a minimum energy for the all-trans conformation. The all-gauche conformation of the main chain of PDPrSM relieves the steric hindrance between side chains found in the all-trans conformation.
AB - The structure of poly(di-n-propylsilylenemethylene) (PDPrSM) has been studied by X-ray diffraction, electron diffraction and molecular modeling. The fiber X-ray data and the electron diffraction pattern of single crystals show that PDPrSM has triclinic symmetry with unit cell parameters a = 10.52 Å, b = 8.66 Å, c = 4.86 Å, α = 78.4°, β = 100.0° γ = 98.2°. The fiber repeat, 4.86 Å, indicates an all-gauche conformation in the main chain, giving a 41 helical structure. Ab initio and semi-empirical energy calculations show that with attachment of n-alkyl side chains an all-gauche conformation for the main chain gives the lowest energy. This is in contrast to the unsubstituted polymer, poly(silaethylene), which has a minimum energy for the all-trans conformation. The all-gauche conformation of the main chain of PDPrSM relieves the steric hindrance between side chains found in the all-trans conformation.
KW - Conformation
KW - Poly(di-n-propylsilylenemethylene)
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=0035110240&partnerID=8YFLogxK
U2 - 10.1016/S0032-3861(00)00766-7
DO - 10.1016/S0032-3861(00)00766-7
M3 - Article
AN - SCOPUS:0035110240
SN - 0032-3861
VL - 42
SP - 4253
EP - 4260
JO - Polymer
JF - Polymer
IS - 9
ER -