Octanuclear {Co6W2} aggregate versus mixed valence {Co}3 cluster in the assembling of Co(phen)2Cl2 (phen = 1,10-phenanthroline) with octacyano metallates: A case of non-isostructurality between {W(CN)8}4− and {Nb(CN)8}4−

An unprecedented octanuclear aggregate, [{Co(phen)2}6{W(CN)8}2Cl2] · Cl2, resulted from the assembling of {Co(phen)2Cl2} and {W(CN)8}4−. Surprisingly, the reaction with the paramagnetic {Nb(CN)8}4− unit did not afford the homologous {Co-Nb} cluster. Instead a mixed-valence [{CoII(phen)2}{CoIII(phen)(CN)4}2] was obtained. Crystal structures and magnetic behaviors are described.