Detour-free synthesis of platinum-bis-NHC chloride complexes, their structure and catalytic activity in the CH activation of methane

Chelating biscarbene ligands are one way to extend the stability of catalysts in homogenous catalysis. Methylene bridged palladium and platinum biscarbene complexes with various counterions have been published, but until now the corresponding chloride complexes were only available by time consuming anion exchange procedures. Here, we present a new direct synthesis for methylene bridged bisimidazolium chloride salts and their platinum biscarbene complexes using dichloromethane as a reagent. Solid state structures of the imidazolium salts and the platinum complexes are reported. The new complexes were successfully tested in the catalytic CH activation of methane.

Graphical abstractWe present a new direct route for the synthesis of methylene bridged bisimidazolium chloride salts as precursors for chelating NHC ligands and their platinum biscarbene complexes using dichloromethane as a reagent. Methylene bridged palladium and platinum biscarbene complexes with various counterions have been published, but until now the corresponding chloride complexes were only available by time consuming anion exchange procedures. Solid state structures of imidazolium salts and platinum complexes are reported. The new complexes were successfully tested in the catalytic CH activation of methane.Figure optionsDownload full-size imageDownload as PowerPoint slide