Ligands donor atoms

The water complexes are high spin, whereas the cyanide and phen complexes are low spin. In the case of the cyanide and phen complexes, the interconversion of the 2g iron(ii) and /2g iron(iii) states simply involves the loss or gain of an electron from the 2g level. Since these are the orbitals oriented between the ligand donor atoms. 

Fig. 3. Ligand donor atoms. The atoms in open blocks are the most common donors, those that axe singly hatched are also common but are very improbable in a biological system, and the doubly hatched donor, F, is of very rare occurrence...

Extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) methods yield information on the number, type, and radial distance of ligand donor atoms bonded to the metal.43 XANES may yield geometric information as well. 

The nature of the ligand donor atom and the stereochemistry at the metal ion can have a profound effect on the redox potential of redox-active metal ions. The standard redox potentials of Cu2+/Cu+, Fe3+/Fe2+, Mn3+/Mn2+, Co3+/Co2+, can be altered by more than 1.0 V by varying such parameters. A simple example of this effect is provided by the couple Cu2+/Cu+. These two forms of copper have quite different coordination geometries, and ligand environments, which are distorted towards the Cu(I) geometry, will raise the redox potential, as we will see later in the case of the electron transfer protein plastocyanin. 

The extended X-ray absorption fine structure (EXAFS) portion of the spectrum extends above the edge in energy and arises from interferences between the photoelectron produced at the edge and photoelectrons backscattered by nearby atoms (e.g. ligand donor atoms) (Scott 1985). The frequency of EXAFS oscillations is directly... 

No Aggregation state Aryl system" Ligand Donor atom 5 / (ppm)... 

Entry Complex type No. of studied complexes Aryl system" Ligand Donor atom X-value (kHz) QSC solid (kHz) QSC solution (kHz)... 

A space model of metal complexes of thia-15-crown-5 shows that the sulfur atom occupies a sizeable fraction of the cavity space. It would be expected, therefore, that the metal ions do not fit into the cavity, but rather either lie above the ligand donor atoms or associate with... 

Ligand Complexa methodb (ligand donor atom) Ref. 

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