取代基对咔咯锰(V)-氧配合物Mn―O的成键影响

Effect of Substituents on Mn―O Bond in Oxo-Manganese(V) Corrole Complexes

用密度泛函理论(DFT)方法对一系列A3型咔咯锰(V)氧配合物进行了理论计算.结果表明:咔咯锰(V)-氧配合物中Mn―O键是由1个σ键和2个π键构成的叁键结构;当咔咯中位取代基由推电子过渡到拉电子性质时,咔咯骨架紧缩,Mn―O键缩短,其拉曼光谱的伸缩振动峰往高波数移动;取代基与氧原子的静电作用模式由正-负吸引转化为负-负排斥,导致Mn―O键解离能ΔE减少,即拉电子基团有利于增强咔咯锰(V)-氧配合物氧原子的活泼性.

Density functional theory （DFT） calculations are used to investigate the effect of substituents on the Mn - O bond in A3-type oxo-manganese（V） corrole complexes. Results indicate that the Mn - O bonds in all the investigated oxo-manganese（V） corrole complexes are triply bonded by one a and two π bonds. As the electron withdrawing ability of the substituents increases, the corrole skeleton contracts, resulting in a decrease in the Mn- O bond length, and the Mn- O Raman stretching vibration shifts to higher wavenumber. As the electrostatic potential of the substituents changes from positive to negative, the electrostatic interaction between oxygen and substituents changes from a negative-positive electrostatic attraction to a negative-negative electrostatic repulsion. Electron withdrawing substituents enhance oxygen reactivity of corrole Mn-oxo complexes by lowering the Mn-O bond dissociation energy.