桑色素铁配合物消除超氧基阴离子自由基的理论研究  

Theoretical Studies of Superoxide Radical Anion Elimination by Morin Iron Complex

作　　者：罗冬梅 鲁涵 丁友健 孔以初 陈书婷 姜家丽 Luo Dongmei;Lu Han;Ding Youjian;Kong Yichu;Chen Shuting;Jiang Jiali(School of Chemistry and Life Sciences,Chifeng University,Chifeng,Inner Mongolia 024000,China)

机构地区：[1]赤峰学院化学与生命科学学院,内蒙古赤峰024000

出　　处：《化学世界》2023年第4期237-248,共12页Chemical World

基　　金：内蒙古科技厅自然科学基金(No.2019MS02030);内蒙古自治区高等学校科学研究(Nos.NJZY20199,NJZY20202);赤峰学院2020年度课程网络教学资源建设(No.WL202017);内蒙古自治区光电功能材料重点实验室基金资助项目。

摘　　要：采用量子化学的密度泛函(DFT)法,用Gaussian 09程序包优化了桑色素(Morin)与Fe^(2+)三种可能的配合物及其与超氧基阴离子自由基(O·―2)相互作用后的几何构型,并在同样的研究条件下计算和分析了三个体系的自然电子布居(NPA)即电荷分布。得到相应的优化几何结构参数、NPA电荷、相互作用能量等。结果表明,所有优化体系均无虚频,结构稳定。Morin-Fe^(2+)配合物与O·―2的相互作用能表明,三种络合方式均对该自由基有良好的消除作用。相互作用能数值在基组重叠误差(BSSE)校正后分别为:7.075 kJ/mol(5,6元环配合物)、-32.832 kJ/mol(5元环配合物)、-59.612 kJ/mol(6元环配合物)。其中Fe^(2+)以六元环的方式与双分子Morin结合的方式与自由基的相互作用能最大,作用结果使得O·―2的NPA电荷增加最多,因此推测强相互作用的主导因素为电荷,这与前线轨道电子云分布一致。最高占据轨道(HOMO)中电子云集中分布在以Fe^(2+)为中心的六元环,分子骨架上共轭体系的电子云向金属中心迁移。最低空轨道(LUMO)中电子云集中分布在以Fe^(2+)为中心的六元环周围,呈现基本对称的分布形式,而金属中心与自由基上分布较少,这与自由基电荷增加相一致。The geometries of three possible complexes of morin molecule with Fe^(2+)and their interaction with superoxide radical anion(O·―2)were optimized by density functional theory method of quantum chemistry.Natural electronic population(NPA)charge distribution of three systems were calculated and analyzed under the same conditions.The optimized geometric structure parameters,NPA charge and interaction energy were obtained.The results showed that all the optimized systems have no virtual frequency and the structure is stable.The results of interaction energy between morin-Fe^(2+)complex and O·-2 revealed that three complex systems have good elimination effect on the free radical.The interaction energy of morin molecule Fe^(2+)5,6-membered ring complex after basis set superposition error(BSSE)correction were 7.075 kJ/mol,5-membered ring complex-32.832 kJ/mol,and 6-membered ring complex-59.612 kJ/mol,respectively.Among them,the interaction energy absolute value between iron ions and free radicals in the six membered ring and bimolecular morin is the largest one,which makes NPA charge of O·―2 increase most at the same time.Therefore,it is speculated that the dominant factor of strong interaction is charge,which is consistent with the distribution of frontier orbital electron cloud.The electron cloud in highest occupied molecular orbitals(HOMO)is concentrated in the six membered ring centered on Fe^(2+)ion and conjugates on the molecular skeleton.The electron cloud of the system migrates to the metal center.The electron cloud in lowest unoccupied molecular orbital(LUMO)is mainly distributed around the six membered ring centered on Fe^(2+)ion,which is basically symmetrical,while the metal center and free radical are less distributed,which is consistent with the increase of free radical charge.

关 键 词：桑色素 超氧基阴离子自由基 Fe^(2+) 量子化学 

分 类 号：O641[理学—物理化学]