Quantification of Substituent Effects in Catalysis by Combined Experimental and Theoretical Charge Density Studies: The Key for Efficient Ligand Tailoring in Catalysis

• Applicant: Professor Dr. Werner R. Thiel
• Subject Area: Analytical Chemistry
• Term: from 2005 to 2008
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5450323

• Final Report Year: 2007

Final Report Abstract

Topological analysis of experimental and theoretical charge densities of several molybdenum bisperoxo benchmarks revealed several criteria which influence/characterize the electronic structure of these catalysts and might allow us to optimize their performance in epoxidation reactions: (i) the different orientation of the oxygen lone pairs in mono vs. bisperoxo complexes might hinder/favour the coordination of the oxidation reactants (organic peroxides) via hydrogen bonding; (ii) electron withdrawing substituents in the pyrazolyl rings apparently trigger not only the A:B isomer ratio but also the ease of the Mo-Npz bond dissociation – which initiates the coordination of the oxidation reactant (organic peroxides).