Isomerization and oxygen atom transfer reactivity in oxo-Mo complexes of relevance to molybdoenzymes.
Both dioxo Mo(VI) and mono-oxo Mo(V) complexes of a sterically restrictive N2O heteroscorpionate ligand are found to exist as cis and trans isomers. The thermodynamically stable isomer differs for the two oxidation states, but in each case, we have isolated the kinetically labile isomer and followed its isomerization to the thermodynamically stable form. The Mo(VI) complex is more stable in the cis geometry and isomerizes more than 6 times faster than the Mo(V) complex, which prefers the trans geometry. In OAT reactions with PPh3, the trans isomer of the dioxo-Mo(VI) reacts approximately 20 times faster than the cis isomer. Thus, there are both oxidation state and donor atom dependent differences in isomeric stability and reactivity that could have significant functional implications for molybdoenzymes such as DMSO reductase.
Hoffman
Justin T
JT
Department of Chemistry, San Diego State University, San Diego, California 92182-1030, USA.
Einwaechter
Simon
S
Chohan
Balwant S
BS
Basu
Partha
P
Carrano
Carl J
CJ
D018360:Crystallography, X-Ray; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D008982:Molybdenum / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D013237:Stereoisomerism; D013816:Thermodynamics
D007506:Iron-Sulfur Proteins; D008024:Ligands; D009942:Organometallic Compounds; D008982:Molybdenum; D010088:Oxidoreductases; C045664:dimethyl sulfoxide reductase; D010100:Oxygen