Metals in Biology: An Attempt at Classification

Fischer‐Hjalmars, Inga; Henriksson-Enflo, A.

doi:10.1016/s0065-3276(08)60350-0

Cited by 21 publications

(11 citation statements)

References 32 publications

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“…The lowest values refer to states obtained by feeding electrons into the IT* ligand orbitals of the complex with n = + 2. From comparison with earlier results [3] iron is expected to keep the character of Fe(I1) in these states. The two states with slightly higher energy are obtained by addition of electrons to the IT* ligand orbitals of the complex with n = + 3.…”

Section: Iron Complexes Of Standard Geometrysupporting

confidence: 73%

“…In the earlier investigations [3] the choice of electron configuration for different values of the overall charge n did not present any problem. For all different combinations of ligating atoms X and metals Be, Mg, Ni, Cu, and Zn the electron configuration for n = + 2 turned out to be the one to be expected from a combination of the metal + 2 ion and two neutral bidentate ligands.…”

Section: Iron Complexes Of Standard Geometrymentioning

confidence: 93%

“…In our earlier studies of the complexes [M(C2H2X2)2]" [3] our main goal was to find general trends within groups of similar compounds, including a series of different metals M as well as different ligating atoms X. In that context it was far beyond the limits of our resources to'optimize the geometry for each complex and each value of the overall charge n. We therefore chose a standard geometry for each group.…”

Section: Choice Of Geometrymentioning

confidence: 99%

“…In an attempt to study the binding between metal and ligand in biosystems, and to gain further insight in the electronic aspects governing biochemical reactions, a series of quantum chemical investigations have been continued in our laboratory for some years (see [3] and further references given there) It is wel1,known that metals in biology often form chelates with five-membered rings, e.g., with amino acids, peptides, catechol structures, etc. In most cases these ligands are unsaturated.…”

Section: Introductionmentioning

confidence: 99%

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Metals in biology: Iron complexes modeling electron transfer

Fischer‐Hjalmars

Holmgrén

Henriksson-Enflo

2009

Int. J. Quantum Chem.

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Complexes of iron-bisglyoxal, [Fe(C2HZ02)2Y, n= +3, +2, + 1, 0, -1, -2, have been studied by a quantum chemical ab iniiio RHF-MO-SCF method. These complexes have basically the same geometric structure as certain iron complexes of catechols and ascorbic acid, and have been employed as models in various studies of metal ion catalysis of chemical oxidation reactions.Our computational results indicate the presence of low-lying excited states. The lowest value of the total energy was obtained for n = -1. This case was studied in more detail. Partial geometry variation was carried out for two close-lying electronic states. It was found that these two states obtain their lowest values for different geometries, and that the two surfaces have an intersection close to these minima.The electronic distribution of the iron in the different states remains unchanged along the energy surfaces, but differs considerably between the states. Both charge distributions and orbital energies indicate that the iron is Fe(I1) in the one state and Fe(II1) in the other. A transfer of the complex from the one energy surface to the other is therefore equivalent to the transfer of an electron between iron and ligand dimer.

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Section: Iron Complexes Of Standard Geometrysupporting

confidence: 73%

Section: Iron Complexes Of Standard Geometrymentioning

confidence: 93%

Section: Choice Of Geometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Metals in biology: Iron complexes modeling electron transfer

Fischer‐Hjalmars

Holmgrén

Henriksson-Enflo

2009

Int. J. Quantum Chem.

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“…The electron affinity of the neutral atom was assumed to be equal to -1.54 eV, the value reported for Hg, another d10s2 atom (Lange, 1973 in Fischer-Hjalmars and Henriksson-Enflo, 1982). The net charge on the Me3S5 cluster, taking into account the charge on the cysteine C0 atoms, was -2.81, which is close to the expected charge of a complex formed from three bivalent metal ions and nine thiolate ligands.…”

Section: Discussionmentioning

confidence: 86%