Density functional theory and MP2 calculations have been used to determine the geometries, stabilities, binding energies, and dissociative properties of cation-diazine complexes M^n＋-C4H4N2 （M^n＋= Li^＋, B^＋, Al^...Density functional theory and MP2 calculations have been used to determine the geometries, stabilities, binding energies, and dissociative properties of cation-diazine complexes M^n＋-C4H4N2 （M^n＋= Li^＋, B^＋, Al^＋, Be^2＋, Mg^2＋, Ca^2＋）. The calculated results indicate that most complexes are stable except the π complexes of Ca^2＋-pyridazine, Ca^2＋-pyrazine, Al^＋-pyrimidine and Al^＋-pyrimidine. The a 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 a complexes, there is stronger covalent interaction between B^＋ and diazine. In the selected π complexes, B^＋ and Be^2＋ have stronger covalent interaction with diazine, while the other cations mainly have electrostatic interaction with diazine.展开更多
基金Project supported by the Open Fund of State Key Laboratory for Physical Chemistry of Solid Surfaces (No. 200306) and Natural Science Fundation of Henan Province (Nos. 0311011200, 200510475012)
文摘Density functional theory and MP2 calculations have been used to determine the geometries, stabilities, binding energies, and dissociative properties of cation-diazine complexes M^n＋-C4H4N2 （M^n＋= Li^＋, B^＋, Al^＋, Be^2＋, Mg^2＋, Ca^2＋）. The calculated results indicate that most complexes are stable except the π complexes of Ca^2＋-pyridazine, Ca^2＋-pyrazine, Al^＋-pyrimidine and Al^＋-pyrimidine. The a 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 a complexes, there is stronger covalent interaction between B^＋ and diazine. In the selected π complexes, B^＋ and Be^2＋ have stronger covalent interaction with diazine, while the other cations mainly have electrostatic interaction with diazine.
