摘要
确定了N [(4 二甲基氨基 ) 苄叉基 ] 2 氨基苯并咪唑 (1) ,N [(4 二甲基氨基 ) -苄叉基 ] 2 氨基苯并噻唑 (2 )和N 苄叉基 1 氨基 -萘 (3)的晶体结构 .利用AM1,RHF ,DFT方法和STO 3G ,4 31G ,6 311G及 6 311G 基组 ,优化每个分子的 2 3个扭曲构象 (θ =0°～ - 89°) .尽管不同方法得到的最优构象的扭角不同 ,分子扭曲的驱动力总是起因于电子作用 .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 .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-{[4-(dimethylamino)phenyl]methylene}-2-benzoimidazoleamine (1), N-{[4-(dimethylamino)phenyl]methylene}-2-benzothiazoleamine (2) and N-(phenylmethylene)-2-naphthaleneamine (3) were determined. Twenty-three rotational geometries (θ=0°～ -89°) of each of the molecules were optimized using AM1, RHF/STO-3G, 4-31G, 6-311G, 6-311G ** and B3LYP/4-31G, 6-311G, 6-311G **. The torsional angles of the preferential geometries of compound 1, 2 and 3 are close to the experimental values (1, θ=- 10.69°; 2, θ= -11.99°; 3, θ= -52.88°) in the case of any optimized method. Although different optimized methods provide a specific molecule with different preferential geometries, the electron interaction always favors a twisted geometry and the nuclear repulsion is, practically, a resistance for distortion of the molecule, which is not an artifact of a specific optimized method. The π system in the geometry with θ=0° is most destabilized no matter whether it is delocalized or not. It appears that the π system always prefers a twisted geometry.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第2期228-233,共6页
Acta Chimica Sinica
基金
国家自然科学基金 (Nos.2 9872 0 42
2 0 0 72 0 41
2 0 0 32 0 10 )资助项目
