Oxo wall
 | It has been suggested that this article be merged into Oxo ligand. (Discuss) Proposed since January 2011. |
The oxo wall is jargon that refers to trends in the area of metal ligand multiple bonds.[1][2] Specifically, the "wall" refers to the long-standing finding that metal oxygen multiple bonding is rare in octahedral transition metal complexes with the configuration d6 or greater.[3]
Complexes of early vs late transition metals
According to ligand field theory for an octahedral complexes with 6 or more d electrons, ligand based electrons of pi-symmetry occupy orbitals that are antibonding with respect to the metal. Where the d-electron count is less than 6, these electrons form multiple bonds with the metal. Thus octahedral iron(II) tends not to form multiple bonds. Iron(IV) readily forms oxo complexes.[4] Such species are invoked in the mechanisms of many oxidase enzymes. For metals with few d-electrons, oxo ligands are routine, e.g. derivatives of vanadyl VO+, such as VOCl3. More famous are the oxo anions of the d0 metals, such as permanganate, chromate, molybdate, and tungstate.
References
- ^ Subhasish Mukerjee, Kirsten Skogerson, Susan DeGala and John P. Caradonna (2000). "Skirting the oxo-wall: characterization and catalytic reactivity of binuclear Co2+/3+ 1,2-bis(2-hydroxybenzamido)benzene complexes with comparison to their isostructural Fe2+/3+ analogs. Implications of d-electron count on oxygen atom transfer catalysis". Inorganica Chimica Acta. 297: 313. doi:10.1016/S0020-1693(99)00431-4.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Mukerjee, S (2000). "Skirting the oxo-wall: characterization and catalytic reactivity of binuclear Co2+/3+ 1,2-bis(2-hydroxybenzamido)benzene complexes with comparison to their isostructural Fe2+/3+ analogs. Implications of d-electron count on oxygen atom transfer catalysis". Inorganica Chimica Acta. 297: 313. doi:10.1016/S0020-1693(99)00431-4.
- ^ Nugent, W. A.; Mayer, J. M. (1988). Metal-Ligand Multiple Bonds: The Chemistry of Transition Metal Complexes Containing Oxo, Nitrido, Imido, Alkylidene, or Alkylidyne Ligands. New York: Wiley-Interscience. ISBN 9780471854401.
- ^ Que, Lawrence; Tolman, William B. (2008). "Biologically inspired oxidation catalysis". Nature. 455 (7211): 333. doi:10.1038/nature07371. PMID 18800132.