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A comparative study of O 2 , CO, and NO binding to iron–porphyrin
Author(s) -
Rovira Carme,
Kunc Karel,
Hutter Jürg,
Ballone Pietro,
Parrinello Michele
Publication year - 1998
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1998)69:1<31::aid-qua5>3.0.co;2-y
Subject(s) - porphyrin , chemistry , imidazole , bond length , diatomic molecule , ligand (biochemistry) , bond energy , crystallography , single bond , bond strength , bond order , molecule , computational chemistry , photochemistry , stereochemistry , crystal structure , organic chemistry , biochemistry , receptor , alkyl , adhesive , layer (electronics)
Minimum‐energy structures of O 2 , CO, and NO iron–porphyrin (FeP) complexes, computed with the Car–Parrinello molecular dynamics, agree well with the available experimental data for synthetic heme models. The diatomic molecule induces a 0.3–0.4 Å displacement of the Fe atom out of the porphyrin nitrogen (N p ) plane and a doming of the overall porphyrin ring. The energy of the iron–diatomic bond increases in the order Fe(SINGLE BOND)O 2 (9 kcal/mol) < Fe(SINGLE BOND)CO (26 kcal/mol) < Fe(SINGLE BOND)NO (35 kcal/mol). The presence of an imidazole axial ligand increases the strength of the Fe(SINGLE BOND)O 2 and Fe(SINGLE BOND)CO bonds (15 and 35 kcal/mol, respectively), with few structural changes with respect to the FeP(CO) and FeP(O 2 ) complexes. In contrast, the imidazole ligand does not affect the energy of the Fe(SINGLE BOND)NO bond, but induces significant structural changes with respect to the FeP(NO) complex. Similar variations in the iron–imidazole bond with respect to the addition of CO, O 2 , and NO are also discussed. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 69: 31–35, 1998