Homoleptic and heteroleptic Au(I) complexes containing the new [Co5C(CO)12]- cluster as ligand

The new [{Co5C(CO)12}Au{Co(CO)4}]–, [1]–, cluster has been obtained from the reaction of [Co6C(CO)15]2– with two equivalents of [AuCl4]–. [1]– reacts with an excess of HBF4 resulting in the formation of [{Co5C(CO)12}2Au]–, [2]–. The new derivatives Co5C(CO)12(AuPPh3), 3, and Co5C(CO)11(AuPPh3)3, 4, have been obtained by reacting [2]– with two and four equivalents, respectively, of Au(PPh3)Cl. All the new species have been structurally characterised by means of X-ray crystallography as their [NEt4][1], [NEt4][2], [NMe3(CH2Ph)][2], 3 and 4•thf•0.5C6H14 salts and solvates. [2]– may be viewed as a homoleptic Au(I) complex containing two [Co5C(CO)12]– clusters as ligands. Similarly, [1]– and 3 are heteroleptic Au(I) complexes containing one [Co5C(CO)12]– cluster ligand as well as [Co(CO)4]– or PPh3. Conversely, 4 contains the [Co5C(CO)11]3– cluster stabilized by three [AuPPh3]+ fragments. [1]– and [2]– have been investigated in solution by means of electrochemical and spectroelectrochemical methods, revealing a very reach redox propensity to form the closely related [1]n– (n = 1-3) and [2]n– (n = 0-3) species.