Organoarsonate Functionalization of Heteropolyoxotungstates

Abstract

Functionalization of the {P8W48} polyoxotungstate (POT) archetype with aromatic organoarsonates results in the first homometallic {P8W48} derivatives, with the general formula [(RAsVO)4PV8WVI48O184]32− [R = C6H5 (1) or p-(H2N)C6H4 (2)]. Short As−O bonds here induce unusual bending of the otherwise rigid {P8W48} macrocycle, breaking its D4h symmetry. The obtained species also represent the first lacunary POTs functionalized with organoarsonates and can potentially act as polyoxometalate precursors themselves. We elaborate solution stability in different aqueous media using 1H and 31P NMR spectroscopy and possible pathways for subsequent transformations in aqueous solutions of the functionalized polyanions. Recrystallization of the K+/Li+/dimethylammonium salt of 2 from 4 M LiCl solution yielded a further functionalized POT, [(H3NC6H4AsO)3P8W48O184Hx{WO2(H2O)2}0.4](30.2−x)− (3), revealing dissociation of the organoarsonate fragments in slightly acidic aqueous solutions followed by their rearrangement within the inner POT cavity.

Synthesis, structure and electrochemical characterization of an isopolytungstate (W4O16) held by MnII anchors within a superlacunary crown heteropolyanion {P8W48}

“…25− in 2005 drew attention to the fact that a cyclic anionic POM {P 8 W 48 } is an excellent superlacunary "molecular container" system for "cluster within cluster" assemblies. 22 Since then {P 8 W 48 } has been investigated widely, and some other 3d-, 4d-, and 4f-transition metals and main group metal derivatives of the archetypal polyanion have been synthesized such as: {Cu 20 -N 3 }, 23 {Cu 20 X (X = Br and I)}, 24 27 {Sn 8 }, 28 {As 4 }, 29 {TM 4 (TM = Co, Mn, Ni, and V)}, 30 {Ru 4 }, 31 {Ln 2 (Ln = La, Ce, Pr, and Nd)}, 32 and {Se4}. 33 The As-analogue [H 4 As 8 W 48 O 184 ] 36− of the cyclic polyanion has been prepared and characterized as well.…”

[(SeO)4P8W48O184]32–: a Tetraselenite‐Embedded Derivative of the Cyclic 48‐Tungsto‐8‐Phosphate

“…This suspended Se–O bonding situation recalls the series of selenite‐templated mixed molybdovanadates, where the pendant SeO 3 2– units act as efficient inorganic ligands and define new architectural principle in the assembly of POM clusters . In addition, the attachment mode of selenite groups to P 8 W 48 through two O bridges strongly reminds the cases of Sn II cations and organoarsonate groups in the corresponding derivatives , …”

“…Thanks to the prominent work of Kortz, Pope, Müller and other groups, the host–guest chemistry based on P 8 W 48 has been extensively investigated and well demonstrated through the isolation of a series of complexes including various metal cations such as copper, iron, vanadium, cobalt, nickel,[7b] manganese,[7b], molybdenum, tin, and lanthanides, or even organoruthenium moieties . In contrast, nonmetallic elements or groups are scarcely involved as guest species for building up the unique structural relationship with the P 8 W 48 host …”

Space-Confined Nucleation of Semimetal-Oxo Clusters within a [H7P8W48O184]33– Macrocycle: Synthesis, Structure, and Enhanced Proton Conductivity

“…Of prime interest, the self-condensation of arsenites in POMs has been seldom observed, where the number of As III centers is usually less than three. − In As 10 , the confined microenvironment offered by P 8 W 48 is kind of beneficial to the controlled hydrolysis–condensation reaction of AsO 3 3– , increasing the number of repeating units up to five. To the best of our knowledge, the polyanion of As 10 represents the first semimetal-oxo cluster-substituted P 8 W 48 , − and accommodates the largest As III -oxo cluster yet found in POMs. − …”

“…; (v) [{Mo 4 O 4 S 4 (H 2 O) 3 (OH) 2 } 2 (P 8 W 48 O 184 )] 36– (Mo 8 @P 8 W 48 ) by Cadot et al; (vi) [{Al 16 (OH) 24 (H 2 O) 8 }­(P 8 W 48 O 184 )] 16– (Al 16 @P 8 W 48 ) and [{Ga 16 (OH) 32 }­(P 8 W 48 O 184 )] 24– (Ga 16 @P 8 W 48 ) by Khashab et al; (vii) [{(W 4 O 16 )­K 10 NaLi 4 Mn 10 (H 2 O) 50 Cl 2 }­(P 8 W 48 O 184 )] 15– (W 4 Mn 6 @P 8 W 48 ) by Ibrahim et al; and (viii) [{Cu 16 (OH) 16 (H 2 O) 4 }­(P 8 W 48 O 184 )] 24– (Cu 16 @P 8 W 48 ) by Suzuki et al Apparently, all of the encapsulated guest clusters in P 8 W 48 are made up of metallic cations. By contrast, semimetallic oxyanions are scarcely involved as guest species, , primarily due to a strong electrostatic repulsion between both negatively charged constituents.…”