Geometrical isomerism in pentadecanuclear high-spin Ni9W6 clusters with symmetrical bidentate ligands detected

Abstract

We have detected the existence of different geometrical isomers of high-spin Ni₉W₆ clusters with symmetrical bidentate blocking ligands, and have proposed the classifications of the isomers. A series of pentadecanuclear body centred full-capped octahedral clusters with symmetrical diimine blocking ligands of the general formula {Ni[Ni(L)(solv)]₈[W(CN)₈]₆}, where L = 2,2′-bipyridine, 4,4′-dimethyl-2,2′-bipyridine, 5,5′-dimethyl-2,2′-bipyridine or 4,4′-ditertbutyl-2,2′-bipyridine and solv = H₂O or EtOH, have been synthesised and structurally characterised. The presence of different crystalline forms and different geometrical isomers have been observed. Since geometrical isomerism in this type of cluster is discussed for the first time, the method of classification of the isomers is proposed. The characterised clusters represent four out of six possible geometrical isomers. Ferromagnetic interactions are present within all clusters resulting in the ground spin state S = 12.