Reactions of bromine-bridged cobalt bis(1,2-dicarbollide) anion with arenes and nucleophiles

•A bromonium derivative of COSAN was characterized by NMR spectra for the first time.•Reactions of 8,8′-μ-Br-3,3′-Co(1,2-C2B9H10)2 with arenes and bases were investigated.•A series of [8-Br-8′-X-3,3′-Co(1,2-C2B9H10)2] derivatives was synthesized.

The generation of Br-bridged complex of cobalt bis(1,2-dicarbollide) (8,8′-μ-Br-3,3′-Co(1,2-C2B9H10)2) and its reactions with arenes and some nucleophiles were studied. The complex 8,8′-μ-Br-3,3′-Co(1,2-C2B9H10)2 can be generated in situ via the action of 8-monobromo derivative of cobalt bis(1,2-dicarbollide) and AlX3 (X = Cl, Br) in different aromatic solvents. This unstable complex was characterized by 11B NMR spectroscopy for the first time. Its reactions with an appropriate arene led to [8-Br-8′-Ar-3,3′-Co(1,2-C2B9H10)2]- species even without addition of an activating Lewis base. Reactions of 8,8′-μ-Br-3,3′-Co(1,2-C2B9H10)2 with S- and N-nucleophiles (thioxane, morpholine) in benzene afforded the corresponding charge-compensated derivatives (8-Br-8′-Y-3,3′-Co(1,2-C2B9H10)2) as well as [8-Br-8′-Ar-3,3′-Co(1,2-C2B9H10)2]- species.

Graphical abstractGeneration of Br-bridged complex of cobalt bis(1,2-dicarbollide) (8,8′-μ-Br-3,3′-Co(1,2-C2B9H10)2) and its reactions with arenes and nucleophiles were investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide