Analogous carbene-stabilised [M I -(η 6 -tol)] + cations (M = Fe, Co, Ni): synthetic access and [carbene·M I ] + transfer

A series of low-coordinate cationic 3d metal(I) complexes of the general formula [IPr·M(η -tol)] is reported (M = Fe, Co, Ni; IPr = [(H)CN(Dip)C:]; Dip = 2,6- Pr -C H ), employing the weakly coordinating [BAr ] counter-anion. The central metal in these complexes is stabilised solely by neutral carbene ( IPr) and arene ( toluene) ligands, making them rare examples of such cationic 3d metal(I) complexes, the electronic nature of which is explored by SQUID magnetometry. The utility of these species in [IPr·M ] transfer chemistry is demonstrated through the addition of a further equivalent of IPr, leading to formally two-coordinate cationic complexes, [(IPr )·M ] .