Comparison of nucleophilic- and radical-based routes to the formation of manganese-main group element single bonds

Abstract

Using the stable metalloradical Mn(CO)₃(CNAr^Dipp2)₂, we report the formation of manganese-main group complexes via the single-electron functionalization of main group halides. The reactions occur in a simple 1 : 1 stoichiometry, and demonstrate the utility of using stable open-shelled organometallics as precursors for metal-main group compounds. This has enabled the preparation of manganese complexes bearing terminal –EX_n substituents, as shown through the isolation of Mn(SnCl)(CO)₃(CNAr^Dipp2)₂ and Mn(BiCl₂)(CO)₃(CNAr^Dipp2)₂ from SnCl₂ and BiCl₃, respectively. Through this approach, we have also isolated Mn(SbF₂)(CO)₃(CNAr^Dipp2)₂ from SbF₃, which serves as a unique example of a terminal –SbF₂ complex. Although the metalloradical functionalization of binary main group halides provides the desired main group adduct in yields comparable to nucleophilic activation using the manganate Na[Mn(CO)₃(CNAr^Dipp2)₂], the former approach is shown to be far more atom-economical with respect to Mn. Additionally, we have found that Mn(CO)₃(CNAr^Dipp2)₂ also serves as a convenient precursor to MnF(CO)₃(CNAr^Dipp2). The latter is an analogue to the elusive monofluoride FMn(CO)₅.