Zr(F^3)与2-丁炔分子自旋禁阻反应C—C,C—H键活化机理的理论研究

Theoretical study of mechanism for C—C,C—H bond activation in spin-forbidden reaction between Zr and 2-butyne

运用密度泛函理论(DFT)B3LYP方法研究了单重态和三重态势能面自旋禁阻反应Zr活化2-丁炔分子的C—C和C—H键的反应机理.通过自旋-轨道耦合的计算讨论了势能面交叉点和可能的自旋翻转过程.反应从基态三重态开始,在活化C—C键的反应过程中出现了自旋态的改变,使得过渡态3 T4g的活化能垒从-3.58降到-10.60kJ·mol-1.在MECP4处,单重态和三重态间的自旋-轨道耦合常数为146.10cm-1,反应发生有效的系间窜越,从三重态跃迁到单重态势能面,反应势垒有所下降.

The mechanism of the spin-forbidden reaction Zr（3F）and 2-butyne on singlet and triplet potential energy surface（PESs）has been investigated by DFT of B3 LYP.Crossing points between the different potential energy surfaces and the possible spin inversion process are discussed by spin-orbit coupling（SOC）calculations.The reacting system starts in the triplet ground state,the changes of the spin state probably occur the activation of C—C,lead to a significant decrease in the barrier height of transition state 3 T4 g from-3.58to-10.60kJ·mol^（-1）.The values of the SOC constants at minimum energy crossing point（MECP4）are146.10cm-1 between singlet and triplet PESs.The effective intersystem crossing（ISC）between different triplet and singlet PESs can occur and obviously reduce energy barriers.