ИСТИНА

Metal carbonyl anions are excellent halogenophilic agents in the reactions with with various polyfluorinated and non-fluorinated vinyl and aryl halides [1]. However,halogenophilic substitution with carbonylmetallate anions in haloalkynes are far less explored, being limited to Cr, Mo and W-centered anions [2]. We have studied the reactions of [Re(CO)5]- and [Mn(CO)5]-anions with diiodoacetylene and found that initially they both form the bis-iodo-acylmetallate complexes, which proves the halogenophilic pathway of the reactions. Manganese complex rearranges in solution to give a new bis-manganate with a bridging cyclobutenedione ligand, analogous to squaric acid anion. Based on the results of DFT calculation (PBE/3Z) the mechanism of the rearrangement is proposed to include 1,2-shift of [IMn(CO)4] group and electrocyclization of bis-ketene intermediate.