A New Route to [SbVW6O24]7- Anderson-Evans Polyoxometalate: Crystal Structures of Na7[SbW6O24]·16H2O and Na7[SbW6O24]·24H2O.

Is It Possible To Prepare a Heterometal Anderson–Evans Type Anion?

“…In our case, [Pt­{Sb­(OH) 2 }­W 5 O 22 ] 7– is formed in a complex reaction between [SbW 9 O 33 ] 9– and [Pt­(H 2 O) 2 (OH) 4 ] involving unknown intermediates. Rearrangement of [Sb III W 9 O 33 ] 9– into [Sb V W 6 O 24 ] 7– has been reported . In our case Pt­(IV) causes stripping of Sb­(V) of its tungstate addenda with the reformation of the Anderson structure around the {Pt IV O 6 } octahedral building bloc, with a {Sb V O 4 (OH} 2 } unit efficiently competing with common {W VI O 4 (O) 2 } for a position in the addenda belt.…”

“…Recently we prepared Na 7 [SbW 6 O 24 ]·16H 2 O ( Sb-1 ) and Na 7 [SbW 6 O 24 ]·24H 2 O ( Sb-2 ) by oxidation of [SbW 9 O 33 ] 9– with bromine in water . In both structures the [SbW 6 O 24 ] 7– anion is not protonated, and the Sb–O bond distances are practically equal (the coordination sphere of Sb V is nearly perfect octahedra).…”

New alkali lanthanide-free polyoxometalates with remarkable water-responsive turn-off–turn-on luminescence properties

“…The microcrystalline powder of K 5 Na 2 [SbW 6 O 24 ]·12H 2 O has been synthesized in water from a one-step synthesis procedure inspired from that previously reported, 40 using K 2 WO 4 and KSb(OH) 6 as the W and Sb sources, respectively. Single crystals of Na 7 [SbW 6 O 24 ]·16H 2 O 39 have been obtained from a new synthetic route using Na 2 WO 4 ·2H 2 O, and SbCl 5 instead of KSb(OH) 6 to avoid the formation of K 5 Na 2 [SbW 6 O 24 ]·12H 2 O as an impurity. The powder X-ray diffraction (PXRD) patterns of both hydrated materials match well with those of their structural models (Fig.…”

“…34,36 The Anderson-type [SbW 6 O 24 ] 7− unit is one of the most performing PL Ln-free POMs, 35 and its potassium salt K 5.5 H 1.5 [SbW 6 O 24 ]·6H 2 O 38 exhibits a green luminescence which is even distinguishable with naked eyes below room temperature. Two other hydrates have been also reported, 39,40 but their PL properties still remain uninvestigated.…”

“…Herein, we postulate that the solid-state emission of alkali [SbW 6 O 24 ] 7− -containing materials could be reversibly tuned by controlling their hydration degree. As a proof of concept, we report a complete study of the precise impact of the thermal dehydration/rehydration processes on the structure, particle size and morphology, and photophysical properties of Na 7 [SbW 6 O 24 ]·16H 2 O , 39 K 5 Na 2 [SbW 6 O 24 ]·12H 2 O , 40 and, the new compound, K 7 [SbW 6 O 24 ]·6H 2 O . First, the thermal behaviors of the three hydrates have been fully investigated by a combination of thermogravimetric measurements, high temperature powder X-ray diffraction (HT-PXRD) analysis, scanning electron microscopy (SEM), and FT-IR and FT-Raman spectroscopies.…”