三元硼氮环的电子结构与成键

Electronic structure and bonding of three-membered boron-nitrogen rings

用从头算ＳＣＦ－ ＭＯ法对三元硼氮环２ 个系列８ 个分子的电子结构进行了研究．根据计算结果，由原子的轨道布居以及σ和π电子的分布，讨论了硼原子与氮原子间的成键情况．结果表明，硼原子和氮原子上加Ｈ 有利于环的稳定，同时削弱了Ｂ—Ｎ 键而增强了Ｂ—Ｂ键和Ｎ—Ｎ 键，对Ｂ２Ｎ 系列和ＢＮ２ 系列中的Ｂ原子和Ｎ 原子的净电荷的影响恰好相反．

The electronic structures of eight molecules in two series of three-membered boron-nitrogen rings have been studied on the ab initio level. The bonding characters between boron and nitrogen atoms were discussed by using the orbital populations and σ -and π -electron distributions. It is shown that the ring stabilities are increased and the B—N bonds are weakened, while B—B, N—N bonds are strengthened by adding hydrogon atoms to either B or N atoms. At the same time, there are different effects on net charge of B and N atom for B 2N and BN 2 series.