锰(Ⅲ)5,10,15-三(五氟苯基)-Corrole配合物的DFT计算

DFT Calculations on Manganese(Ⅲ)5,10,15-Tris(pentafluorophenyl)-Corrole

在6-31G*水平上采用DFT(UB3LYP)方法对锰(III)5,10,15-三(五氟苯基)-corrole[(TPFC)MnIII]及其咪唑轴向配位加合物(TPFC)MnIII(Im)进行了几何结构全优化.计算结果表明,咪唑的配位作用不会改变其基态的高自旋(s=2)特性.(TPFC)MnIII与咪唑配位形成轴向加合物后,其中心金属Mn原子偏离平面结构,与corrole大环N4平均平面的距离达到0.02734nm.NBO分析显示(TPFC)MnIII和(TPFC)MnIII(Im)中心金属锰的电子组态为(dxz)1(dyz)1(dz2)1(dx2-y2)1(dxy)0.(TPFC)MnIII(Im)前线分子轨道能级明显上升,从其β-(LUMO+3)轨道可见咪唑配位N原子的py轨道与中心金属Mn原子dyz轨道形成了d-pπ轨道.TD-DFT计算发现,(TPFC)MnIII和(TPFC)MnIII(Im)电子光谱Q带的"四轨"特征比B带明显;(TPFC)MnIII的CT带主要源自β-(HOMO-1)→β-(LUMO+5)和β-HOMO→β-(LUMO+4)的跃迁,(TPFC)MnIII(Im)的CT带则主要源自β-(HOMO-1)→β-(LUMO+3)和β-HOMO→β-(LUMO+4)的跃迁.

Geometries of manganese （Ⅲ） 5,10,15-tris（pentafluorophenyl） corrole （TPFC）Mn^Ⅲ and its imidazole axial binding adduct （TPFC）Mn^Ⅲ（Im） were optimized by using DFT（UB3LYP） method at 6-31G^ ＊ basis set level. Calculation results indicated that （TPFC）Mn^Ⅲ and （TPFC）Mn^Ⅲ（Im） had the same spin state （s=2） in their ground states. （TPFC） Mn^Ⅲ had a plane structure, while Mn atom in （rPFC）Mn^Ⅲ（Im） was above the corrole N4 mean plane 0.02734 nm. NBO analysis showed that the electronic configuration of central Mn atom in （TPFC）Mn^Ⅲ and （TPFC）Mn^Ⅲ（Im） was （dxz）^1（dyz）^1（dz2）^1（dx2-y2）^1（dxy）^0. The energies of frontier orbitals of （TPFC）Mn^Ⅲ（Im） were significantly higher than those of （TPFC）Mn^Ⅲ, and the Mn-imidazole d-pπ bonding could be found from β-（LUMO＋3） obital of （TPFC）Mn^Ⅲ（Im）. In addition, electronic spectra of （TPFC）Mn^Ⅲ and （TPFC）Mn^Ⅲ（Im） were calculated by using TD-UB3LYP/6-31G^＊ method, and it could be found that Q band had more ＂four-orbital＂ characters than B band. CT band of （TPFC）Mn^Ⅲ was mainly contributed from β-（HOMO- 1） to β-（LUMO＋5） and β-HOMO to β-（LUMO＋4） transitions, and CT band of （TPFC）Mn^Ⅲ（Im） was mainly contributed from β-（HOMO-1） to β-（LUMO＋3） and β-HOMO to β-（LUMO＋4） transitions.