摘要
通过HF/3- 2 1G从头计算求得琥珀酰苯胺 (PHSIM)和联丁二酰亚胺(BSIM )的内旋转位能曲线 ,在密度泛函理论B3LYP/6 - 31G 水平对能量极小点所对应的稳定构型进行全优化 ,并作集居数分析、自然键轨道分析和简正振动分析 ,获得它们的几何构型、电子结构、红外光谱和热力学性质。结果表明 ,PHSIM和BSIM均以非平面构型存在 ,前者分子中五员环和六员环之间的夹角约为 4 3°;后者的 2个五员环平面相互垂直。它们分子中羰基伸缩振动带均分裂为 2个 ,在PHSIM中为 1 74 0cm-1 、1 795cm-1 ,而在BSIM中为 1 773cm-1 、1 80 2cm-1 ,且低频带的振动强度远大于高频带。由振动频率计算了标题物在 2 98～ 80 0K温度范围的热力学函数 。
Rotational potential energy curves of N Phenylsuccinimide (PHSIM) and N,N’ Bisuccinimide (BSIM) have been calculated at the ab initio HF/3-21G level. Geometry optimizations have been performed subsequently on the energy minima at the B3LYP/6-31G * level of density functional theory, and population, natural bond orbital and normal mode vibrational analyses have been carried out. The geometries, electronic structures, infrared spectra and thermodynamic properties have been obtained. Only one twisted stable conformer exists for each compound. The included angle between the five and six membered rings in PHSIM is 43°, while in BSIM, two five membered rings are perpendicular. The CO stretch vibration splits into two bands in these compounds (1 740 cm -1 and 1 795 cm -1 in PHSIM, and at 1 773 cm -1 and 1 802 cm -1 in BSIM), and the lower frequency band is much stronger than the higher one. The thermodynamic functions have been evaluated via the vibration frequecy, at 298～800 K and the heat of formation has been estimated via atomization reactions.
出处
《南京理工大学学报》
EI
CAS
CSCD
北大核心
2003年第3期323-327,共5页
Journal of Nanjing University of Science and Technology
关键词
密度泛函理论
构象
光谱
热力学性质
density functional theory,conformation,spectrum,thermodynamic function
