Synthesis, characterization and crystal structures of [Ir9H(CO)19]4– and [Ir10(CO)21]2–

Abstract

The base-induced condensation of [Ir₄(CO)₁₂] at room temperature has yielded [Ir₉(CO)₂₀]^3– and [Ir₉H(CO)₁₉]^4–, which both reveal a face-sharing bioctahedral metallic framework; oxidation of [Ir₉(CO)₂₀]^3– produced [Ir₁₀(CO)₂₁]^2–, after addition of a butterfly-capping iridium atom; these clusters have been compared with known compounds of ruthenium, rhodium and iridium, which together model the building-up process of the closed-shell trigonal-bipyramidal polyhedron; step-by-step growth shows irregularities in the number of valence electrons, since the larger clusters require more filled orbitals than predicted by the capping principle.