低温基质隔离红外光谱和从头算研究CF_2O…IF

Matrix Isolation IR Spectra and Ab Initio Study of CF_2O…IF Complexes

在10K Ar和Xe基质中测得CF_2O…IF的两种分子间配合物A和B的红外光谱,观察到A和B之间的异构化反应.采用量子化学从头计算,在MP_2/LANL2DZ水平上计算得到A和B的平衡构型的结构参数和振动频率.IF与CF_2O的相互作用引起CF_2O的C(?)O双键伸长、C—F键缩短,导致v_C=O的红移和V_(CF_2)的蓝移.由势能曲线可看出,A的势能比B高23kJ/mol,表明B比A稳定,升温能够发生A向B的转化.

Two CF2O…IF complexes have been found during laser photolysis of CF3I/O2 in Ar and Xe matrices. The geometries and fundamental vibrational frequencies of two complexes CF2O…IF (A) and CF2O…IF(B) have been determined by ab initio calculations at MP2 level with the LANL2DZ basis set. The calculated potential energies indicate that the complex(B) is more stable than the complex(A) by 23kJ/mol. The frequencies and stability are in agreement with the experimental results.