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

doi:10.3321/j.issn:0251-0790.2001.01.023

CORC > 北京大学 > 化学与分子工程学院

	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 ; 宣正乾 ; 郭彦伸 ; 彭晓琪 ; 王桐信 ; 金祥林
刊名	高等学校化学学报
	2001
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 resonance effect driving force for distorting stilbene-like species conformation N-phenylmethylene-2-thiazoleameine N-(4-Nitrophemyl)methylene-2-thiazoleameine
DOI	10.3321/j.issn:0251-0790.2001.01.023
英文摘要	确定了N-苄叉基-2-氨基噻唑(2a)和N-对硝基苄叉基-2-氨基噻唑(2b)的晶体结构.结合已报道的N-对硝基苄叉基-2-氨基嘧啶(1a)，N-对硝基苄叉基-2-氨基吡啶(1b)和N-苄叉基-3-氨基吡啶(2c)的晶体结构.利用AM1，RHF，DFT方法和6-311G，6-311G基组，优化每个分子的22个旋转构象(θ=0°～90°).由DFT法所得到的最优构象的扭角θ(1a，22°；1b，0°；1c，42°；2a、2b：0°)与实验值(1a，26°；1b，20°；1c，46°；2a，8.8°；2b，3.8°)最接近.尽管分子最优构象扭角的差异很大，但总电子能最稳定的构象都在θ=±42°附近.在任一分子、任何电子态中，离域的π体系总是失稳定的，全平面构象不是π体系最稳定的构象.无论是离域的还是定域的π体系，它们均倾向于扭曲的几何构象.π电子的离域是分子扭曲的驱动力之一.与经典观点相反，非键原子间的核排斥作用是分子扭曲的阻力，而不是动力.; 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.; 国家自然科学基金; 国家重点基础研究发展计划(973计划); SCI(E); 中文核心期刊要目总览(PKU); 中国科学引文数据库(CSCD); 4; 1; 122-126; 22
语种	中文
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/210940]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	虞忠衡,宣正乾,郭彦伸,等. 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[J]. 高等学校化学学报,2001.
APA	虞忠衡,宣正乾,郭彦伸,彭晓琪,王桐信,&金祥林.(2001).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.高等学校化学学报.
MLA	虞忠衡,et al."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".高等学校化学学报 (2001).