高等学校化学学报2001，Vol.22Issue(1)：122-126,5.
N-苄叉基-2-氨基噻唑及其类似物的构象和分子内的扭曲驱动力
The Conformation of N-Phenylmethylene-2-thiazoleamine Species and the Driving Forces for Twisting Molecule
虞忠衡 1宣正乾 1郭彦伸 1彭晓琪 1王桐信 1金祥林2
作者信息
- 1. 中国科学院化学研究所,
- 2. 北京大学化学与分子工程学院,
- 折叠
摘要
Abstract
The crystal structures of N-phenylmethylene-2-thiazoleamine (2a) and N-[(4-nitrophenyl) methylene]-2-thiazoleamine (2b) were determined.Twenty-two rotational geometries (θ=0°～ 90°) of each of two molecules were optimized using AM1,RHF/6-311G**,B3LYP/6-311G and B3LYP/6-311G**.The twist angles of their preferential geometries obtained from DFT are both 0°,which are most close to the experimental values (2a,θ=8.9°; 2b,θ=3.9°) of all angles obtained from various optimized methods.Although there is a great difference in the twist angles of the five molecules,2a,2b,N-(4-nitrophrnyl)methylene-2-pyrimidineamine (1a),N-(4-nitrophenyl)methylene-2-pyridine-amine (1b) and N-phenyl) methylene-3-pyridineamine (1c),their lowest total electronic energies occur in the optimized geometries with the similar twist angles which are in the region of θ from 37 to 42° and almost have nothing to do with the optimized methods (HF and DFT) and Gaussian basis sets.The π system in the geometry with θ= 0° is destabilized no matter whether it is delocalized or not.It appears that the π system always prefers a twisted geometry.The driving force for out-of-plane twist of the molecules arises from the electronic interaction,and the nuclear repulsion is,practically,a resistance for distortion of molecule.关键词
共轭效应/扭角驱动力/构象/N-苄叉基-2-氨基噻唑/N-对硝基苄叉基-2-氨基噻唑分类
化学化工引用本文复制引用
虞忠衡,宣正乾,郭彦伸,彭晓琪,王桐信,金祥林..N-苄叉基-2-氨基噻唑及其类似物的构象和分子内的扭曲驱动力[J].高等学校化学学报,2001,22(1):122-126,5.
