【摘要】 用量子化学的密度泛函理论方法对BX3(X=H,F,Cl)与烯烃CnH2n(n=2,3,4)形成的复合物进行了研究,结果表明,复合物的构型皆为BX3位于烯烃π键的上方,并且偏向氢原子数较多的碳原子一侧。C-C双键中的π电子通过向BH3中B的空p轨道转移电子而形成复合物,但BF3和BCl3与烯烃分子只是通过微弱的分子间作用力结合,复合物的形成使分子的振动光谱随作用的强弱而出现一定的红移现象。更多还原

【Abstract】 Geometries and combination energies for the complexes between alkenes C_nH_2n（n=2,3,4） and BX₃（X=H,F,Cl） are predicated at B3LYP/6-311+G（2d,p） level. The results show that the BX₃ locate exactly above the double bond of alkenes and close to the terminal carbon atoms to which there are more hydrogen atoms attached. The complexes of BH₃ are formed based on the fact that the π electrons of the double bond transfer to the empty p orbital of boron atoms. But the formations of the complexes about BF₃ and BCl₃ are only rely on the weak intermolecular forces. The calculated outcomes show that when the complex formed their vibration spectrum move to the red side and the frequency shifts are relative to the stabilities of the complexes.更多还原