Synthesis of Complexes with Protic NH,NR‐NHC Ligands by Oxidative Addition of N ‐Alkyl‐2‐iodoimidazoles to [M(PPh 3 ) 4 ] (M = Pd, Pt) Complexes

The oxidative addition of N ‐methyl‐2‐iodoimidazole ( 1 ) or N ‐benzyl‐2‐iodoimidazole ( 2 ) to complexes [Pd(PPh 3 ) 4 ] or [Pt(PPh 3 ) 4 ] followed by the protonation of the unsubstituted imidazolato ring nitrogen atom yielded complexes trans ‐[M(NH,NMe‐NHC)(PPh 3 ) 2 I]PF 6 (M = Pd: trans ‐[ 3 ]PF 6 ; M = Pt: trans ‐[ 4 ]PF 6 ) and trans ‐[M(NH,NBz‐NHC)(PPh 3 ) 2 I]PF 6 (M = Pd: trans ‐[ 5 ]PF 6 ; M = Pt: trans ‐[ 6 ]PF 6 ) bearing imidazole‐derived protic NH,NR‐NHC ( p NHC) ligands. In the absence of a proton source, the reaction of 1 with [Pd(PPh 3 ) 4 ] yielded the dinuclear dipalladium complex [ 7 ] featuring bridging imidazolato ligands metalated at the C2 ring‐carbon atom and the N3 ring‐nitrogen atom. Palladium complex trans ‐[ 3 ]PF 6 undergoes halogen abstraction with AgPF 6 to give acetonitrile complex trans ‐[Pd(NCCH 3 )(NH,NMe‐NHC)(PPh 3 ) 2 ](PF 6 ) 2 trans ‐[ 8 ](PF 6 ) 2 . This complex reacts further with 1,10‐phenanthroline (phen), affording complex [Pd(NH,NMe‐NHC)(PPh 3 )(phen)](PF 6 ) 2 [ 9 ](PF 6 ) 2 .