Rare direct imidation of aromatic metallacycle by reaction of CpCo(dithiolene) complex with N-halosuccinimide

Abstract The aromatic [CpCo(S 2 C 2 (R)(H))] (R = Ph, Me, 9-phenanthryl, H) complexes reacted with N -halosuccinimides (NXS; X = Cl, Br, I) in carbon tetrachloride at room temperature to undergo the N -succinimide substitution reaction on the dithiolene ring, but no halogenated dithiolene complex was obtained. The imidation products [CpCo(S 2 C 2 (R)( N -sccinimide))] were yielded up to 64% where X = I and R  = 9-phenanthryl. The reaction of [CpCo(S 2 C 2 (Ph)(H))] with N -bromophthalimide (NBP) also gave the imidation product [CpCo(S 2 C 2 (Ph)( N -phthalimide))]. This is the rare direct imidation reaction to an aromatic metallacycle by NXS. The reaction of [CpCo(S 2 C 2 H 2 )] (R = H) with NIS afforded the double imidation product. One by-product in this reaction was the dithiolene–dithiolene homo-coupling product [CpCo(S 2 C 2 (R))] 2 (R = Ph, Me, 9-phenanthryl). The microwave-enhanced (MW) reactions were attempted in the carbon tetrachloride solution. Although the solution temperature increased up to only 43 °C by MW irradiation, the imidation reaction worked with short reaction time.