Pt(PPh_3)_2-η~2C_(60)络合物的分子轨道研究

MOLECULAR ORBITALS STUDY IN Pt(PPh_3)_2-(η~2C_(60))

近年来,自Kratschmer 等人采用并不复杂的方法就能制备出宏观量的C_(60),人们对它的兴趣也从结构的研究逐渐转向化学性质的研究.C_(60)是目前自然界已知对称性最高的球状分子,每个C 原子都以接近sp^2杂化轨道和相邻的三个C 原子相联.C_(60)的NMR 化学位移以及闭壳层的电子结构和较宽的HOMO-LUMO 间隙,都说明它具有典型的芳香化合物——苯的某些特性.另外,掺杂(碱金属元素)后,它具有的导电性又表现出石墨具有的某些特点.

The molecular orbitals of the complex Pt(PPh_3)_2-η~2(C_(60))were investigated viaFenske-Hall molecular orbital calculations on the prototype species Pt(PH_3)_2-η~2C_(60).The results was compared with typical π-complex Pt(PPh_3)_2-η~2C_2H_4.The results ofcalculation showed that the components of HOMO and LUMO in Pt(PH_3)_2-η~2C_(60) main-ly come from C_(60),which is the electron acceptor,but the components of HOMOand LUMO in Pt(PH_3)_2-η~2C_2H_4 molecular orbitals mainly come fromPt(PH_3)_2,which is the electron donor.The ligand C_(60) and C_2H_4 both act as an ac-ceptor,but C_(60) is more stronger than C_2H_4.The LUMO of Pt(PH_3)_2-η~2C_(60) is stillsituated at lower energy and it is possible to accept further Pt(PH_3)_2 radical on C_(60)surface.From the calculation it was revealed that there are two conjujated chainstarted on atoms C1 and C6.The Mulliken charge is distributed along these chain al-ternatively.