New carbide clusters in the cobalt sub-group. Part 14. Synthesis and structural characterization of the anion [Co13C2(CO)24]3– as its benzyltrimethylammonium salt

Abstract

The anion [Co₁₃C₂(CO)₂₄]^3– has been obtained by oxidation of the corresponding paramagnetic tetra-anion with iodine in MeCN. Its molecular structure has been determined by single-crystal X-ray diffractometry, showing that the two anions are isostructural. The metal-atom polyhedron contains two trigonal-prismatic cavities in which two interstitial carbon atoms are accommodated. Average bond distances are Co–Co 2.575 Å and Co–C(carbide) 1.97 Å. The effect of the removal of the unpaired electron from the parent tetra-anion is discussed. A comparison of structural parameters is reported.