Hada Masahiko
Department of Chemistry, Faculty of Science, Tokyo Metropolitan University, Hachioji, Tokyo, 192-0397, Japan.
J Am Chem Soc. 2004 Jan 21;126(2):486-7. doi: 10.1021/ja038097n.
Accurate quantum-chemical calculations were carried out for bis(cyanide) and cyanide-imidazole Fe(III) porphyrins in the ground and low-lying excited states including both the ferric (dxy)2(dxz,yz)3 and (dxy)1(dxz,yz)4 configurations. The trans-ligand effect on the paramagnetic 13C NMR chemical shifts of the iron-bound 13CN- was well reproduced by the present calculations. Further, in bis(cyanide)(meso-tetraethyl) Fe(III) porphyrin, which has a ruffled porphyrin ring, the (dxy)1(dxz,yz)4 configuration is included in the ground state, and the alternative (dxy)2(dxz,yz)3 configuration is located closely in energy to the ground state. Ruffling of porphyrin rings extremely affects the 13C chemical shift of iron-bound CN in the (dxy)1(dxz,yz)4 configuration but not in the (dxy)2(dxz,yz)3 configuration.
对双（氰化物）和氰化物-咪唑铁（III）卟啉在基态和低激发态进行了精确的量子化学计算，包括铁（III）的（dxy）2（dxz，yz）3和（dxy）1（dxz，yz）4构型。本文计算很好地再现了反式配体对铁结合的13CN-顺磁13C NMR化学位移的影响。此外，在具有褶皱卟啉环的双（氰化物）（中-四乙基）铁（III）卟啉中，基态包含（dxy）1（dxz，yz）4构型，而另一种（dxy）2（dxz，yz）3构型在能量上与基态非常接近。卟啉环的褶皱对（dxy）1（dxz，yz）4构型中铁结合的CN的13C化学位移有极大影响，但对（dxy）2（dxz，yz）3构型则没有影响。
