Lin Tao, Zhang Weijiang, Wang Lichang
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
J Phys Chem A. 2008 Dec 25;112(51):13600-8. doi: 10.1021/jp805748b.
The structures, energetics, and binding characteristics of complexes formed between anisole (C(6)H(5)OCH(3)) and boron trifluoride (BF(3)) were investigated using MP2 and B3LYP methods with 6-31+G(d,p) and 6-311+G(d,p) basis sets. Among the complexes with a 1:1 ratio of C(6)H(5)OCH(3) to BF(3), both B3LYP and MP2 methods predict the same structures and relative stability of the isomers; however, the B3LYP binding energies are smaller than the MP2 energies. Furthermore, the weaker the interaction, the greater the discrepancy in binding energy. The charge decomposition analysis (CDA) showed that there are two types of complexes: the Lewis acid-base adduct and the van der Waals complexes. The CDA results also illustrated that there is a significant donation from the oxygen lone pair electrons to the boron vacant orbital in the adduct. The van der Waals complexes were formed through the aromatic ring and BF(3) interaction or through the H and F interactions. The MP2 results showed that the formation of adduct at room temperature is thermodynamically favorable. Among the 1:2 C(6)H(5)OCH(3)-BF(3) complexes, the most stable structure consists of both the Lewis acid-base and van der Waals binding; i.e., one BF(3) binds with C(6)H(5)OCH(3) to form C(6)H(5)OCH(3) x BF(3) adduct, while the other BF(3) binds with this adduct through van der Waals interactions. The calculated binding energy of the 1:1 complex is close to the experimental heat of formation, which suggests that the 1:1 complexes are the most likely species in the C(6)H(5)OCH(3) and BF(3) mixture.
采用MP2和B3LYP方法以及6-31+G(d,p)和6-311+G(d,p)基组，研究了苯甲醚（C(6)H(5)OCH(3)）与三氟化硼（BF(3)）形成的配合物的结构、能量和结合特性。在C(6)H(5)OCH(3)与BF(3)比例为1:1的配合物中，B3LYP和MP2方法预测的异构体结构和相对稳定性相同；然而，B3LYP结合能小于MP2能量。此外，相互作用越弱，结合能的差异越大。电荷分解分析（CDA）表明存在两种类型的配合物：路易斯酸碱加合物和范德华配合物。CDA结果还表明，在加合物中，氧孤对电子向硼空轨道有显著的电子给予。范德华配合物是通过芳环与BF(3)相互作用或通过H与F相互作用形成的。MP2结果表明，室温下加合物的形成在热力学上是有利的。在1:2的C(6)H(5)OCH(3)-BF(3)配合物中，最稳定的结构同时包含路易斯酸碱和范德华结合；即一个BF(3)与C(6)H(5)OCH(3)结合形成C(6)H(5)OCH(3) x BF(3)加合物，而另一个BF(3)通过范德华相互作用与该加合物结合。计算得到的1:1配合物的结合能接近实验生成热，这表明1:1配合物是C(6)H(5)OCH(3)和BF(3)混合物中最可能存在的物种。
