Analogous carbene-stabilised [MI-(η6-tol)]+ cations (M = Fe, Co, Ni): synthetic access and [carbene·MI]+ transfer

Abstract

A series of low-coordinate cationic 3d metal(I) complexes of the general formula [IPr·M(η⁶-tol)]⁺ is reported (M = Fe, Co, Ni; IPr = [(H)CN(Dip)C:]; Dip = 2,6-ⁱPr₂-C₆H₃), employing the weakly coordinating [BAr^F₄]⁻ counter-anion. The central metal in these complexes is stabilised solely by neutral carbene (i.e. IPr) and arene (i.e. 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^I]⁺ transfer chemistry is demonstrated through the addition of a further equivalent of IPr, leading to formally two-coordinate cationic complexes, [(IPr₂)·M^I]⁺.