A Keggin‐Type Structure Expanded by an Eight‐Membered Ring of Alternating Edge‐Sharing VO₅ and VO₆ Polyhedra: Solvothermal Synthesis, Crystal Structure, and Magnetic Properties

Interconvertible vanadium-seamed hexameric pyrogallol[4]arene nanocapsules

“…1 ) yields J/k = −653.8 K and g = 2.04 (Supplementary Figure 9 ). Both the curve and negative J indicate dominant antiferromagnetic exchange interactions within this capsule since χ m T at 300 K is much smaller than the expected values from 24 isolated V 4+ spin carriers 68 . Notwithstanding all V centers being at +4 oxidation states in both V 24 capsules, the variations between the five-coordinated square-pyramidal geometries in the V 24 -ball-β and the six-coordinated octahedral geometries in the V 24 -oct-α are indicative of a sensitive magnetic behavior of V 4+ centers in different ligand field environments.…”

Small, beautiful and magnetically exotic: {V4W2}- and {V4W4}-type polyoxometalates

“…5 Few other small W/V complexes are known with N-and O-donor ligand environments: in [L′O(H 2 O)V IV (μ-O)W VI O 2 L] 2+ (L = 1,4,7-triazacyclononane, L′ = 1,4,7-trimethyl-L), VN 3 O 2 and WN 3 O 2 moieties are µ-oxobridged, 6 in [V 2 O 2 (μ-OMe) 2 (μ-WO 4 ) 2 (4,4′-di-tert-butyl-2,2′-bipyridine) 2 ], two VN 2 O 3 units are bridged by two WO 4 groups. 12) in the presence of tris(2-aminoethyl)amine (tren), 8 (Fig. 12) in the presence of tris(2-aminoethyl)amine (tren), 8 (Fig.…”

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Minimal-nuclearity vanadato-tungstate clusters in [{V IV (dien)} 4 -W VI 2 O 14 ]·4H 2 O (1) and [{V IV (dien)} 4 W VI 4 O 20 ]·6H 2 O (2) feature cores of edge-sharing WO 6 octahedra, surrounded by a ring of four vanadyl groups. 12) in the presence of tris(2-aminoethyl)amine (tren), 8 we now were able to isolate [(V(dien)) 4 W 2 O 14 ]·4H 2 O (1) and [(V(dien)) 4 W 4 O 20 ]·6H 2 O (2) (dien = diethylenetriamine, C 4 H 13 N 3 ) under similar con-ditions, where a higher reactant V : W ratio (1 : 3 vs. 1 : 4) appears to favor a smaller W nuclearity. 1 The first mixed V-W polyanions were reported already in the 19 th century; 2 efficient synthesis protocols were developed for the Lindqvisttype polyanions [V x W 6−x O 19 ] −2−x (x = 1, 2), 3 the solution stability of which is strongly pH dependent.

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“…7 After identifying a {V 13 W 4 }-type extended Keggin structure under solvothermal conditions at high pH (ca. 12) in the presence of tris(2-aminoethyl)amine (tren), 8 we now were able to isolate…”