Synthesis and characterization of a dinuclear Ni complex containing a bridging CNC pincer ligand

The reaction of the bis(carbene) pincer ligand MeCNC with nickel acetate and Bu4NBr produced [(MeCNC)3Ni2]4+[Br]4 (2), a complex that contains the MeCNC ligand in both traditional tridentate chelating modes as well as in a unique, bridging mode between two Ni2+ ions. While 2 could not be crystallized or isolated in a pure form, the anion exchange of bromide with triflate yielded [(MeCNC)3Ni2]4+[OTf]4 (4), which could be recrystallized from methanol and isolated pure. Single-crystal X-ray analysis of 4 confirmed the unusual dual-coordination modes of the MeCNC ligand towards Ni2+ in these species, and represents the initial example of a Group 10 complex of a bridging CNC ligand.