Here we study the effect of metals on the characteristic Soret band of N-confused porphyrins. We used DFT calculations to study how this low-lying region of the spectrum of the NCP-2H isomer is affected by the introduction of transition metals with various ($d^2$, $d^3$, $d^4$ and $d^6)$ d-electron configurations. The spin ground state of these complexes is mostly dependent on the number of unpaired electrons, both with and without the presence of an axial ligand. The analysis of the electronic distribution and spin density showed that these unpaired electrons are often harbored by the N-confused porphyrin ring instead of on the metal. Time-dependent DFT results indicated that the aromatic system of porphyrin is disrupted in the N-confused isomer: instead of the typical large Soret band, this now gives rise to two peaks of much lower intensity. Most metallo-porphyrins exhibited similar optical properties, with the HOMO/LUMO orbitals showing a mixed metal/porphyrin character. The only exception was the Rh metalloporphyrin that exhibited a ligand-to-metal charge transfer band with increasing intensity as function of the ligand field. This suggests Rh is the only metal whose orbitals are higher in energy than the ligand’s, indicating that it is the only system where the redox processes occur on the metal.

在这里，我们研究了金属对氮混淆卟啉特征索雷特谱带的影响。我们使用 DFT 计算来研究 NCP-2H 异构体光谱的这个低位区域如何受到引入各种过渡金属的影响（$d^2$,$d^3$,$d^4$和$d^6）$d 电子构型。这些配合物的自旋基态主要取决于不成对电子的数量，无论是否存在轴向配体。对电子分布和自旋密度的分析表明，这些不成对的电子通常被N-混淆的卟啉环所隐藏，而不是在金属上。时间依赖性 DFT 结果表明，卟啉的芳香系统在 N-混淆异构体中被破坏：而不是典型的大 Soret 带，现在产生了两个强度低得多的峰。大多数金属卟啉表现出相似的光学性质，HOMO/LUMO 轨道表现出金属/卟啉的混合特征。唯一的例外是 Rh 金属卟啉，它表现出配体到金属的电荷转移带，其强度随着配体场的函数而增加。这表明 Rh 是唯一轨道能量高于配体轨道能量的金属，表明它是金属上发生氧化还原过程的唯一系统。