Theoretical Studies on the Interactions of Cations with Diazine

• 作 者: CHEN Xing WU Wen-Peng ZHANG Ji
• 机 构: Institute of Fine Chemistry and Engineering,Department of Chemistry and State Key Laboratory for Phy
• 出 处: 结构化学
• 发表日期: 2004年期
• 关键词: DFT and MP2 calculations cation-diazine complexes cation-molecule interactions
• 基金项目: the Open Fund of State Key Laboratory for Physical Chemistry of Solid Surfaces;河南省自然科学基金

Density functional theory and MP2 calculations have been used to determine the geometries, stabilities, binding energies, and dissociative properties of cation-diazine complexes Mn+-C4H4N2 (Mn+ = Li+, B+, Al+, Be2+, Mg2+, Ca2+). The calculated results indicate that most complexes are stable except the π complexes of Ca2+-pyridazine, Ca2+-pyrazine, Al+-pyrimidine and Al+-pyrimidine. The σ complexes are generally much more stable than their π counterparts. Among the π complexes, the cation-pyrazine π complexes have slightly higher stability. The nature of the ion-molecule interactions has been discussed by the natural bond orbital analysis and frontier molecular orbital interactions. In these σ complexes, there is stronger covalent interaction between B+ and diazine. In the selected π complexes, B+ and Be2+ have stronger covalent interaction with diazine, while the other cations mainly have electrostatic interaction with diazine.