New Perspectives for Old Clusters: Anderson-Evans Anions as Building Blocks of Large Polyoxometalate Frameworks in a Series of Heterometallic 3 d-4 f Species

• Published in: Chemistry : a European journal 2016-03, Vol.22 (13), p.4616-4625
• Main Authors: Artetxe, Beñat, Reinoso, Santiago, San Felices, Leire, Lezama, Luis, Gutiérrez-Zorrilla, Juan M., Vicent, Cristian, Haso, Fadi, Liu, Tianbo
• Format: Article
• Language: English
• Subjects: Anions - chemistry; Cerium - chemistry; cluster compounds; Crystallography, X-Ray; Lanthanoid Series Elements - chemistry; Organometallic Compounds - chemistry; polyoxometalates; self-assembly; supramolecular chemistry; Tungsten Compounds - chemistry; X-ray diffraction
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201504768

A series of nine [Sb7W36O133Ln3M2(OAc)(H2O)8]17− heterometallic anions (Ln3M2; Ln=La–Gd, M=Co; Ln=Ce, M=Ni and Zn) have been obtained by reacting 3 d metal disubstituted Krebs‐type tungstoantimonates(III) with early lanthanides. Their unique tetrameric structure contains a novel {MW9O33} capping unit formed by a planar {MW6O24} fragment to which three {WO2} groups are condensed to form a tungstate skeleton identical to that of a hypothetical trilacunary derivative of the ɛ‐Keggin cluster. It is shown, for the first time, that classical Anderson–Evans {MW6O24} anions can act as building blocks to construct purely inorganic large frameworks. Unprecedented reactivity in the outer ring of these disk‐shaped species is also revealed. The Ln3M2 anions possess chirality owing to a {Sb4O4} cluster being encapsulated in left‐ or right‐handed orientations. Their ability to self‐associate in blackberry‐type vesicles in solution has been assessed for the Ce3Co2 derivative. Refurbished building blocks: A series of nine heterometallic 3 d–4 f anions are obtained from the reaction of 3 d‐metal disubstituted Krebs‐type precursors with early lanthanides. These anions display constituent units from another archetypal family of clusters that has never been noted to act as a building block of any large polyoxometalate framework: the planar Anderson–Evans {MW6O24} species (see figure).