New Catalyst Systems for the Catalytic Conversion of Methane into Methanol

Palladium complexes with N-heterocyclic carbenes, such as in the biscarbene chelate ligands shown (R=tBu, Me; X=Br, I), have proved to be stable in strongly acidic media and were tested in the catalytic conversion of methane into methanol. The prominent influence of the halogenide ligand is shown since, in contrast to the bromo complex, the iodo complex does not catalyze the reaction. The steric bulk of the substituents R also influences the catalytic activity.