Synthesis and Characterization of Heteromultinuclear Ni/M Clusters (M = Fe, Ru, W) Including a Paramagnetic (NHC)Ni–WCp*(CO)3 Heterobinuclear Complex

A diverse range of heteromultinuclear NiI/[MCO] clusters (MCO = CpFe­(CO)2, CpRu­(CO)2, Cp*W­(CO)3) supported by an N-heterocyclic carbene ligand have been synthesized by reacting the NiI precursor, [IPrNi­(μ-Cl)]2, with [MCO]− reagents under various conditions. Clusters with Ni2Fe2, NiFe2, Ni2Ru, Ni2Ru2, NiRu2, and Ni2W and NiW cores were all characterized using NMR and IR spectroscopy and X-ray crystallography. The NiI-containing paramagnetic heterobinuclear species IPrNi-Wp* (7) was further characterized by EPR spectroscopy and DFT calculations. Notably, unlike previously studied (NHC)­CuI-[MCO] derivatives, complex 7 was found to coordinate Lewis bases such as 3-chloropyridine to produce (IPr)­(3‑Clpy)­NiWp* (9). Complex 9 further underwent thermolytic C–Cl activation, proposed to involve NHC-free [(3‑Clpy)­Ni­(μ-Wp*)]2 (10), to provide the C-arylated N-heterocyclic carbene product [IPr­(py-3-yl)]+[Cp*WCl2(CO)2]− (11).