Density Functional Studies of Iron-Porphyrin Cation with Small Ligands X (X: O, CO, NO, O2, N2, H2O, N2O, CO2)
Density Functional Studies of Iron-Porphyrin Cation with Small Ligands X (X: O, CO, NO, O2, N2, H2O, N2O, CO2)
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DOI：
10.1021/jp9032657
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发表时间：
2009-08-13
影响因子：
2.9
通讯作者：
Renger, Thomas
中科院分区：
文献类型：
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作者：
Abdurahman, Ayjamal;Renger, Thomas
小配体X （X: O， CO， NO, O-2, N-2, H2O, N2O）的铁卟啉阳离子[FeP]（+）的分子结构。采用密度泛函理论（DFT）方法，利用LANL2DZ基集对交换相关（XC）泛函OPBE和B3LYP进行了研究。所有配合物的相对自旋态能和键离解能均以其优化的几何形状表示。低自旋（S 1/2, S = 0）态是[FePO]（+）、[FePCO]（+）和[FePNO]（+）配合物的最低能态，而高自旋（S = 5/2）态是[FePO2]（+）配合物的最低能态。[FePN2]（+）、[FePH2O]（+）、[FePN2O]（+）和[FePCO2]（+）配合物的中间自旋态（S = 3/2）为最低能态，且与分离的[FeP]（+）表现出相同的相对自旋态能量顺序：(S = 3/2) < (S = 5/2) < (S = 1/2)， fe -配体成键非常弱。利用OPBE xc -官能团方法计算出的键解离能对于最低能量自旋态的顺序为：N2O < CO2 < N-2 < O-2 < H2O < CO < NO < O.这一理论水平之前被证明是唯一能够正确预测铁化合物自旋基态的DFT方法，我们在本研究中发现了OPBE xc -官能团类似的良好性能。
Molecular structure of the iron porphyrin cation [FeP](+) with small ligands X (X: O, CO, NO, O-2, N-2, H2O, N2O. CO2) are studied employing density functional theory (DFT) methods with the exchange-correlation (XC) functionals OPBE and B3LYP using the LANL2DZ basis set. The relative spin state energies and bond dissociation energies of all of the complexes are presented at their optimized geometries. The low-spin (S 1/2, S = 0) state is found to be the lowest energy states for the [FePO](+), [FePCO](+) and [FePNO](+) complexes whereas the high-spin (S = 5/2) state has the lowest energy for the [FePO2](+) Complex. The intermediate-spin (S = 3/2) state is found to be the lowest energy states for the [FePN2](+), [FePH2O](+), [FePN2O](+), and [FePCO2](+) complexes which exhibit the same relative spin-state energy ordering: (S = 3/2) < (S = 5/2) < (S = 1/2) as isolated [FeP](+), and the Fe-ligand bonding is very weak. The calculated bond dissociation energy using the OPBE XC-functional method has shown the following order for the lowest energy spin state: N2O < CO2 < N-2 < O-2 < H2O < CO < NO < O. This level of theory was previously shown to be the only DFT method capable of correctly predicting the spin ground state of iron compounds, and we find similar good performance of OPBE XC-functional in the current study.