Periodic Trends and Fluxionality Effects on Transition Metal Catalyzed Sulfoxidation

Area of Science:

• Organometallic Chemistry
• Catalysis
• Oxidation Reactions

Background:

• d0 metal complexes are of interest for peroxide activation and oxygen transfer.
• Microscopic mechanistic details of these catalytic processes remain incompletely understood.

Purpose of the Study:

• To investigate sulfide oxidation using cumyl hydroperoxide with a series of eight d0 metal aminotriphenolate complexes.
• To elucidate the reaction mechanisms, reactivity, selectivity, and the influence of Lewis bases on these catalytic systems.
• To correlate experimental kinetic data with theoretical predictions and electronic properties.

Main Methods:

• Experimental kinetic studies of sulfide oxidation catalyzed by Ti(IV), Zr(IV), Hf(IV), V(V), Nb(V), Ta(V), Mo(VI), and W(VI) aminotriphenolate complexes.
• Investigation of the effect of dimethylhexyl-N-oxide as a Lewis base.
• Correlation of reactivity with Sanderson electronegativity values.
• Density Functional Theory (DFT) calculations to model catalytic cycles and peroxo species.

Main Results:

• Reactivity and selectivity trends were observed across the series of d0 metal complexes.
• The influence of the Lewis base on catalytic performance was quantified.
• Kinetic data correlated with Sanderson electronegativity, suggesting electronic effects on reactivity.
• DFT calculations provided detailed insights into the mechanisms involving peroxo intermediates.

Conclusions:

• Proposed mechanistic pathways for sulfide oxidation catalyzed by eight different d0 metal aminotriphenolates.
• Rationalized periodic trends in reactivity and selectivity based on metal identity.
• Highlighted the unique catalytic behavior of flexible vanadium complexes.