Geometric and electronic structures of Os₃(CO) ₉(μ₃-n²,n²,n²-C ₆₀), Os₃(CO)₈(P(CH₃) ₃)(μ₃-n²,n²,n²-C ₆₀), and Their Anions (Q = -1 to -4): Reduction-induced conversion of π to σ C₆₀-metal complexes

The geometries and electronic structures of Os₃(CO) ₉(μ₃-n²,n²,n²-C ₆₀), Os₃(CO)₈(P(CH₃) ₃)(μ₃-n²,n²,n²-C ₆₀), (OsF2), and their mono-, di-, tri-, and tetra-anions were calculated using a density functional method. Our calculations show that all three Os atoms are coordinated to C₆₀ in a ;π-type mode for the mono- and dianions, as well as in the neutral OsF1 and OsF2 complexes, but that third and fourth electron reductions form mixed σ-π-type coordinated compounds. A third electron reduction produces the Os₃(CO) ₉(μ₃-n²,n²,n¹-C ₆₀)^3- and Os₃(CO)₈(P(CH ₃)₃)(μ₃-n²,n²,n ¹-C₆₀)^3- complexes, while a fourth electron reduction produces the Os₃(CO)₈(P(CH₃) ₃)(μ₃-n²,n¹,n¹-C ₆₀)^4- and Os₃(CO)₈(P(CH ₃)₃)(μ₃-n²,n²,n ¹-C₆₀)^4- complexes. Our reduction potentials are calculated, in qualitatively good agreement with experimental data obtained using cyclic voltammetry.