Ab initio investigation of boron-centered superhalogen anions B(SO₄)₂⁻ and B(S₂O₃)₂⁻: structures, stability, and electrochemical properties

Two boron-centered molecular anions, B(SO 4 ) 2 – and B(S 2 O 3 ) 2 – , were investigated using ab initio methods, with particular attention to their structural, electronic, and electrochemical stability. Equilibrium structures and relative stabilities of selected isomeric forms were determined at the MP2/6–311 + G* level, while vertical electron detachment energies were calculated using the OVGF method. The most stable structures were found to involve bidentate coordination of the sulfate or thiosulfate ligands to the boron center and to display high electronic stability, with VDE values exceeding those of simple halide anions. Fragmentation analysis indicated that the lowest energy isomers are thermodynamically stable with respect to the considered dissociation pathways. Formal redox potentials evaluated in selected organic solvents showed that B(SO 4 ) 2 – retains electrochemical stability comparable to common electrolyte anions, whereas B(S 2 O 3 ) 2 – is less oxidatively robust. The corresponding Li, Na, and K salts were also examined as potential halogen-free electrolyte components.