含钼过氧配气物催化硫醚和烯烃氧化反应机理理论研究  

Theoretical studies on mechanism of oxidation of methylsulfide and ethylene by[Mo(O)(O_2)_2(pz)_2]

作　　者：孙国峰[1] 胡育[1] 曾鸿耀[1] 唐典勇[1] 

机构地区：[1]乐山师范学院化学学院,四川乐山614000

出　　处：《化学研究与应用》2013年第12期1655-1660,共6页Chemical Research and Application

基　　金：四川省教育厅资助项目(10ZA033);乐山市科技局重点项目(12GZD065;12GZD038)资助项目;乐山师范学院青年教师启动项目(1152)

摘　　要：在B3LYP/Aug-cc-pvdz-pp水平下,对双过氧钼配合物Mo(O)(O2)2(pz)2(pz=pyrazolyl)氧化二甲硫醚,二甲亚砜和乙烯分别形成二甲亚砜,二甲砜和环氧乙烷的反应机理进行详细理论研究并进行了分子中原子理论拓扑分析。计算结果表明,三种氧化反应均只经历一个过渡态,即底物中的反应中心原子(硫醚和亚砜为硫原子,乙烯为C=C双键平面)向[Mo(O)(O2)2(pz)2]中过氧的一个原子靠拢形成过渡态,从而形成产物。过渡态均为协同过渡态,由底物向[Mo(O)(O2)2(pz)2]中过氧原子转移电子而发生氧化反应。二甲硫醚氧化反应的自发性最小,二甲亚砜和乙烯氧化反应热自发性相当,三个反应在热力学上均可行。二甲硫醚的氧化和二甲亚砜的氧化在常温下可以达到99%选择性。如果有过量氧化剂的存在,亚砜就会进一步氧化为砜。在相同条件下,硫醚和亚砜的氧化不会影响烯烃,烯烃氧化需要另外条件以降低活化能,与钼配合物和多钼酸盐氧化硫醚,亚砜和烯烃反应的实验研究结果趋势相同。The mechanism of the oxidation of methyl sulfide, dimethyl sulfoxide, and ethylene by[Mo（O）（O2）2（pz）2] was investi- gated in detail at the B3 LYP/ang-cc-PVDZ-PP level. The quantum theory of atom-in-molecules （QTAIM） was used to discuss bond natures and orbital interactions. The computational results indicated that all of the three reactions proceeded via only one transition state to form the products. The transition state was the attack of the reaction center of substrates（ sulfur atoms for methyl sulfide and dimethylsulfoxide, C = C plane for ethylene） by one of oxygen atom of the peroxide in [ Mo（O）（O2）2（pz）2 ], The transition state was a synergistic transition state. The electron was transferred from the substrate to the oxygen atom of peroxide in [ Mo （O） （ 02 ） 2 （pz）2 ]. All of them were spontaneous at room temperature. The thioethem and sulfoxides could be efficiently oxidized to the corre- sponding products under mild conditions with high activity and excellent selectivity and even actively group was also tolerated in the oxidation,such as olefin group.

关 键 词：氧化反应 密度泛函理论 分子中原子理论 反应机理 化学选择性 

分 类 号：O643.12[理学—物理化学]