吡啶-BH~3相互作用复合物的理论研究

对吡啶-BH~3复合物分别用MP2/6-31+G^*和B3LYP/6-31+G^*进行理论计算以预测该复合物的构型及解离能，得到四种构型，在MP2优化构型基础上作CCSD/6-31+G^*单点能量计算以验证MP2与B3LYP结果的可靠性，然后用B3LYP作振动频率分析，计算了各构型的垂直电离势，最后用更大基组作单点能量计算和自然键轨道(NBO)分析。结果表明，N-B直接相连的构型最稳定，其解离能为141.50kJ/mol,MP2和B3LYP对N-H接近的构型结果相关较大，另外两种构型稳定性介于二者之间，解离能分别为15.18kJ/mol,14.06kJ/mol(MP2/6-31+G^*)。

Theoretical study of the pyridine-BH~3 interaction complex

Geometries and dissociation energies are predicated at MP2/6-31 + G* and B3LYP/6-31 + G* levels respectively. Single point energy calculations using CCSD method at 6-31 + G* level are also carried out on the four obtained conformers to confirm the results. Then vibrational analysis are made using B3LYP/6-31 + G* method. Single point energy calculations at much larger basis sets and natural bond orbital analysis have been also carried out on the optimized conformers. The outcome indicates that the conformer with the boron atom directly connected to the nitrogen atom is the most stable one with a dissociation energy of 141.50 kJ/ mol. The results for the conformer with the nitrogen atom close to one of the hydrogen atom in BH3 differ from each other at MP2 and B3LYP levels. The stability of the other two conformers (with boron atom lying on one of the pyridine carbons) is between that of the aforementioned two conformers and their dissociation energies are 15.18 and 14.06 kJ/mol (MP2/6-31 + G* ) , respectively.