中文摘要：

采用量子化学的密度泛函B3LYP和二阶微扰MP2（full）方法对C4H4Y（Y=O,S,Se）与BX3（X=H,F,Cl）形成的电子授受型复合物进行了研究,所得18个复合物的构型包括BX3位于C=C双键上方的π-p作用型和B与O,S,Se直接作用的n-p作用型.体系C4H4Y-BH3以n-p作用型较为稳定,体系C4H4Y-BF3,C4H4Y-BCl3的π-p和n-p作用型复合物稳定性相当.对各复合物的几何构型、振动频率和自然键轨道分析表明,复合物的形成过程中均存在几何构型的改变、电荷的转移和振动频率的变化,它们的变化规律与复合物稳定性的变化规律基本一致,即按H,F,Cl的顺序依次降低.

英文摘要：

The geometries and binding energies of the complexes between C4H4Y（Y=O,S,Se） and BX3 （X=H,F,Cl） have been calculated at the density function theory B3LYP and the second-order M？ller-Plesset theory MP2（full） levels.The vibration and natural bond orbital analyses were carried out,which indicate that the 18 conformers obtained include π-p interaction （the BX3 locating exactly above the C=C double bond） and n-p interaction （the boron atom directly combining to O,S or Se）.The stabilities of C4H4Y-BH3 complexes are in the order of n-pπ-p.The stabilities of C4H4Y-BF3 and C4H4Y-BCl3 complexes with n-p interaction are relative to the π-p type complexes.The calculated results show that charge transfers,frequency shifts and change of geometries are relative to the stabilities of the complexes in the forming process.