Conformational Characteristics of Poly(tetramethylene oxide)
Conformational Characteristics of Poly(tetramethylene oxide)
复制标题
聚四亚甲基氧的构象特征
DOI：
10.1021/ma971234e
复制
发表时间：
1998
期刊：
影响因子：
5.5
通讯作者：
Yuji Sasanuma
中科院分区：
文献类型：
--
作者：
R. V. Law;Yuji Sasanuma
在6-31+G* 基组下，采用分子轨道从头计算方法，在二级Moller−Plesset关联水平上计算了聚四氢呋喃（PTMO）的单体模型1，4-二甲氧基丁烷（DMB）的构象能，并在此基础上研究了PTMO的构象特征.通过比较DMB的NMR邻位13 C −1H和1H−1H偶合常数以及PTMO的特征比和偶极矩比的计算值和观测值，检验了我们构象能的可靠性。然后，从先前报道的聚环氧丙烷的单体模型化合物1，2-二甲氧基丙烷的MO和1H NMR数据确定用于聚醚的旋转异构态分析的C-O键偶极矩（mC-O）。最佳mC-O值为1.18 D。构象能很好地再现了实验观察。讨论了聚醚的构象特征与晶体结构的关系。
Conformational characteristics of poly(tetramethylene oxide) (PTMO) have been investigated on the basis of the conformational energies evaluated for its monomer model 1,4-dimethoxybutane (DMB) from the ab initio molecular orbital (MO) calculations at the second-order Moller−Plesset correlation level with the 6-31+G* basis set. The reliability of our conformational energies was examined by comparison between calculations and observations of NMR vicinal 13C−1H and 1H−1H coupling constants of DMB and the characteristic ratio and dipole moment ratio of PTMO. Then the C−O bond dipole moment (mC-O) for the rotational isomeric state analysis of polyethers was determined from the MO and 1H NMR data reported previously for 1,2-dimethoxypropane, a monomeric model compound of poly(propylene oxide). The optimal mC-O value was obtained as 1.18 D. The conformational energies reproduced the experimental observations very well. The relationship between the conformational characteristics and crystal structures of polyethe...