Synthesis of Palladium and Platinum Complexes with an NH, NEt‐substituted Benzimidazolin‐2‐ylidene Ligand

The compound 2‐chloro‐ N ‐ethylbenzimidazole 1 was synthesized and was reacted with complexes of type [ M (PPh 3 ) 4 ] ( M = Pd, Pt) in the presence of NH 4 BF 4 as proton source. This reaction leads via an oxidative addition to complexes of type [ M Cl(NH, NEt‐NHC)(PPh 3 ) 2 ]BF 4 ( M = Pd, [ 3 ]BF 4 ; M = Pt, [ 4 ]BF 4 ). In case of M = Pd, only compound trans ‐[ 3 ]BF 4 was obtained, while for M = Pt two isomeric platinum complexes cis ‐[ 4 ]BF 4 and trans ‐[ 4 ]BF 4 were obtained in a ratio of 78:22. The molecular structures of the square‐planar complexes trans ‐[ 3 ](BF 4 ) and cis ‐[ 4 ]BF 4 were determined by X‐ray diffraction.