Local Effective Crystal Field Combined with Molecular Mechanics. Improved QM/MM Junction and Application to Fe(II) and Co(II) Complexes
| Autor: | M. B. Darkhovskii, Andrei L. Tchougréeff |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry A. 108:6351-6364 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp036622z |
| Popis: | The quantum mechanical effective Hamiltonian of crystal field (EHCF) methodology (previously developed for describing electronic structure of transition metal complexes) is combined with the Gillespie−Kepert version of molecular mechanics (MM) in order to describe multiple potential energy surfaces (PES) of the Werner-type complexes corresponding to different spin states of the latter. The procedure thus obtained is a special version of the hybrid quantum mechanics/molecular mechanics approach. The MM part is responsible for representing the whole molecule, including ligand atoms and metal ion coordination sphere, but leaving aside the effects of the d shell. The quantum mechanics part (EHCF) is restricted to the metal ion d shell. The method reproduces with considerable accuracy geometry and spin states of a wide range of Fe(II) and Co(II) complexes of various total spin and coordination polyhedra and containing both monodentate and polydentate ligands with aliphatic and aromatic nitrogen donor atoms. In... |
| Databáze: | OpenAIRE |
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