Details

Autor(en) / Beteiligte

• Merca, Alice
• Schnack, Jürgen
• van Slageren, Joris
• Glaser, Thorsten
• Bögge, Hartmut
• Hoeke, Veronika
• Läge, Mechtild
• Müller, Achim
• Krebs, Bernt

Titel

Systematic Study of the Interaction Between VIV Centres and LnIII Ions in Well Defined {V2IVLnIII}{AsIIIW9O33}2 Sandwich-Type Clusters: Part 2

Ist Teil von

• Journal of cluster science, 2013-12, Vol.24 (4), p.979-988

Ort / Verlag

Boston: Springer US

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The gadolinium (Gd) member of a new type of heteropolytungstates that contain one lanthanide and two transition metal ions in a triangular arrangement is reported. The compound NaK 6 Gd 0.33 [((VO) 2 Gd(H 2 O) 4 K 2 (H 2 O) 2 (Na)(H 2 O) 2 )(α-B-AsW 9 O 33 ) 2 ]·24H 2 O ( 1 ) was prepared from acidified aqueous solutions of Na 2 WO 4 ·2H 2 O, As 2 O 3 and VOSO 4 ·5H 2 O to which Gd 3+ ions were added. The single crystal X-ray structure analysis (monoclinic, space group P 2 1 / m ) shows that the anion consists of two [α-B-As III W 9 O 33 ] 9− trilacunary Keggin-type units linked by two VO 2+ , one Gd 3+ as well as weakly by two K + and one Na + ions, resulting in a sandwich-type structure with idealized C 2v symmetry. The problem of positioning crystal lattice and special polyoxometalate sites with different cations is discussed also in connection with supramolecular chemistry aspects and as an option for further research. A fit of the magnetic susceptibility yielded exchange coupling constants of J VV  = −2.55 cm −1 (anti-ferromagnetic) between the vanadium ions and J GdV  = 0.6 cm −1 (ferromagnetic) between the Gd and each of the two vanadium ions. The complete magnetochemical analysis also revealed a partial occupancy of the Na + sites in the counter-cation–water system by Gd 3+ ions (0.33 Gd 3+ ions in total).