[Bi7M3(CO)3]2- (M = Co, Rh): a new architype of 10-vertex deltahedral hybrids by the unprecedented polycyclic η5-coordination addition of Bi73- and trimetallic fragments

Redox reactions of K5Bi4 and CpCo(CO)(2)/Rh(CO)(2)(acac) (acac = acetylacetonate) in ethylenediamine (en) yielded the first Bi-7(3-) adducts [Bi7M3(CO)(3)](2-) (M = Co, 1a; Rh, 2a) that have a new architype 10-vertex deltahedral structure, resulting from the unprecedented polycyclic eta(5)-coordination addition reaction of the Bi-7(3-) cage and three MCO+ fragments.