三羰基(三甲硅基)环戊二烯基钼负离子及其钼氢化合物的电子结构及化学键研究

Study on electronic structure and chemical bond of metallocene [(Me_3SiC_5H_4)Mo(CO)_3]^- and [(Me_3SiC_5H_4)MoH(CO)_3]

用G98W程序和Lanl2dz基组,全结构优化三羰基(三甲硅基)环戊二烯基钼负离子[(Me_3SiC_5H_4)Mo(CO)_3]^-(Ⅰ)及三羰基(三甲硅基)环戊二烯基钼氢化合物[(Me_3SiC_5H_4)MoH(CO)_3](Ⅱ)。振动频率分析和单点能计算结果表明,位于环戊二烯环(Cp)上的钼能形成半夹心结构的"稳定"化合物。其键长、原子电荷、分子轨道成份和前沿轨道能都表明,钼原子与环戊二烯通过p-d作用形成"氢键",Cp环碳上的p电子和Mo原子d轨道的电子,向钼原子的p轨道转移,形成电荷转移配位化合物。

Ab initio method with Lanl2DZ basis sets has been used to optimize the possible geometries of the triearbonyl trimethylsilyl- cyclopentadienyl molybdenum anion [ （ Me3SiC5H4 ） Mo（CO） 3 ]^ - （ Ⅰ ） and triearbonyl trimethylsilyl eyclopentadienyl molybdenum-hydrogen [ （Me3SiC5H4） MoH（CO） 3 ] （ Ⅱ ） complexes. The single point energy calculation results show that the most stable geometries of （ Ⅰ） and （ Ⅱ ） complexes are the configuration where the molybdenum is located above the eyelopentadienyl ring. The calculated vibrational frequency show that the structures are reasonable. The bond lengths, total atomic charge, the coefficients of the molecular orbitals,frontier orbital energies of the complexes indicate that the interaction between molybdenum and eyelopentadienyl anion involve p- d interaction. On the other hand, electron is transferred from the d orbital of molybdenum atom with p orbital of carbon （eyelopentadienyl） to p orbital of molybdenum,and thus gives charge transfer complexes. The calculated results also imply that the interaction characteristic of the molybdenum-cyelopentadienyl anion complexes are similar to hydrogen bonding.