摘要
采用密度泛函理论B3LYP方法研究了咔咯锰(Ⅴ)氧配合物(Mn^(Ⅴ)O corrole)与苯乙烯氧原子转移(oxygen atom transfer,OAT)反应途径和吸电子取代基的影响。计算结果发现氧原子进攻苯乙烯中双键的β碳原子形成过渡态,结合内禀反应坐标法(intrinsic reaction coordinate method,IRC)和最小能量交叉点(minimum-energy crossing point,MECP)计算,给出该反应发生直接氧转移的机理。咔咯大环中位连的吸电子五氟苯基可通过改变锰原子的亲电性,加大取代基与氧原子的静电排斥作用,增加Mn^(Ⅴ)O corrole的氧化性。反应能垒随五氟苯基数目的增加而降低,且三重态的反应能垒明显低于单重态。体系可从单重态反应物开始,在MECP处易发生自旋翻转并形成三重态,然后以能量更低的三重态过渡态反应路径进行氧转移反应直至生成产物。
The oxygen atom transfer(OAT)reaction pathway of the reaction between styrene and manganese(Ⅴ)⁃oxo corrole complexes(Mn^(Ⅴ)O corrole)was investigated using the density functional theory B3LYP method.The calcula⁃tion results showed that the oxygen atom attacked theβcarbon atom of the olefinic double bond in styrene to form a transition state,and the direct oxygen atom transfer pathway was determined via the intrinsic reaction coordinate method(IRC)and the minimum⁃energy crossing point(MECP)calculation.The meso⁃pentafluorophenyl group of Mn^(Ⅴ)O corrole can change the electrophilicity of the manganese atom and increase electrostatic repulsion between the substituent and the oxygen atom,leading to the improvement of oxygen transferability of Mn^(Ⅴ)O corrole.With the increase of the pentafluorophenyl group number at the Mn^(Ⅴ)O corrole,the reaction energy barrier decreases accord⁃ingly.Furthermore,the reaction energy barrier of the triplet state is significantly lower than that of the singlet state pathway,indicating that spin exchange is prone to occur and the reaction proceeds via triplet state pathway.In the OAT reaction pathway,the reactants in singlet state reach to MECP position firstly,and then change to the triplet state with spin over easily.After that,the reactants follow the triplet state pathway with a lower transition state to achieve the product.
作者
曾琪
徐艳
陈华彬
许旋
徐志广
刘海洋
ZENG Qi;XU Yan;CHEN Hua-Bin;XU Xuan;XU Zhi-Guang;LIU Hai-Yang(School of Chemistry,South China Normal University,Guangzhou 510006,China;School of Chemistry and Chemical Engineering,South China University of Technology,Guangzhou 510641,China)
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2022年第1期39-45,共7页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金项目(No.21671068)
广东省自然科学基金项目(No.S2012010008763)资助。
关键词
咔咯
锰氧配合物
苯乙烯
取代基效应
氧原子转移反应
最小能量交叉点
corrole
manganese⁃oxo complex
styrene
substituent effect
oxygen atom transfer reaction
minimum⁃energy crossing point
