Bioinspired hydrogen bond motifs in ligand design: the role of noncovalent interactions in metal ion mediated activation of dioxygen.
Hydrogen bonds influence secondary coordination spheres around metal ions in many proteins. To duplicate these features of molecular architecture in synthetic systems, urea-based ligands have have been developed that create rigid organic frameworks when bonded to metal ions. These frameworks position hydro-gen bond donors proximal to metal ion(s) to form specific chem-ical microenvironments. Iron(II) and manganese(II) complexes with constrained cavities activate O(2), yielding M(III) (M(III) = Fe and Mn) complexes with terminal oxo ligands. Installation of anionic sites within the cavity assists the formation of complexes with M(II/III)-OH and M(III)-O units derived directly from water. Opening the cavity promotes M(mu-O)(2)M rhombs, as illustrated by isolation of a cobalt(III) analogue, the stability of which is promoted by the hydrogen bonds surrounding the bridging oxo ligands.
Borovik
A S
AS
Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
D003035:Cobalt / Q000737:chemistry; D005296:Ferrous Compounds / Q000737:chemistry; D006860:Hydrogen Bonding; D007477:Ions; D008024:Ligands; D017895:Manganese Compounds / Q000737:chemistry; D008667:Metalloproteins / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D013816:Thermodynamics
D005296:Ferrous Compounds; D007477:Ions; D008024:Ligands; D017895:Manganese Compounds; D008667:Metalloproteins; D008670:Metals; D009942:Organometallic Compounds; D010087:Oxides; D003035:Cobalt; C027424:manganese oxide; D010100:Oxygen