An assessment of pure, hybrid, meta, and hybrid-meta GGA density functional theory methods for open-shell systems: The case of the nonheme iron enzyme 8R-LOX

作者：Bushnell Eric A C^*; Gauld James W

来源：Journal of Computational Chemistry, 2013, 34(2): 141-148.

DOI：10.1002/jcc.23114

• lipoxygenase
• density functional theory
• open-shell
• transition metal

The performance of a range density functional theory functionals combined in a quantum mechanical (QM)/molecular mechanical (MM) approach was investigated in their ability to reliably provide geometries, electronic distributions, and relative energies of a multicentered open-shell mechanistic intermediate in the mechanism 8RLipoxygenase. With the use of large QM/MM active site chemical models, the smallest average differences in geometries between the catalytically relevant quartet and sextet complexes were obtained with the B3LYP* functional. Moreover, in the case of the relative energies between 4II and 6II, the use of the B3LYP* functional provided a difference of 0.0 kcal mol1. However, B3LYP +/- and B3LYP also predicted differences in energies of less than 1 kcal mol1. In the case of describing the electronic distribution (i.e., spin density), the B3LYP*, B3LYP, or M06-L functionals appeared to be the most suitable. Overall, the results obtained suggest that for systems with multiple centers having unpaired electrons, the B3LYP* appears most well rounded to provide reliable geometries, electronic structures, and relative energies.

• 出版日期2013-1-15