Trimetallo derivatives of lacunary 9-tungstosilicate heteropolyanions. Part 1. Synthesis and charaterization

A Mixed‐Valence Manganese Cubane Trapped by Inequivalent Trilacunary Polyoxometalate Ligands

“…The characteristic sharpness of the oxidation wave is indicative of the presence of a surface-active species. [18] At different scan rates we found that the W-centered and the first Mncentered peak currents were proportional to the square root of the scan rate, thus indicating a diffusion-controlled process, while the second Mn-centered peak currents were found to be proportional to the scan rate, thus indicating a surfacecontrolled process specifically at low values of scan rate (5-20 mV s À1 ). Furthermore, the electrochemical behavior of 1 was studied by solid-state electrochemistry measurements (see the Supporting Information).…”

Design of Tri‐Substituted Dodecatungstosilicate from a Trilacunary Silicotungstate by Insertion of Manganese Ions of [Mn3(μ3‐O)(2‐Cl‐benzoato)6(py)3]: Synthesis, Structure, Redox and Magnetic Studies

“…Although, dilacunary tungstosilicates have been used extensively by different groups, [2,6,7] the use of trilacunary tungstosilicates for surface modification of POMs is limited. [8] Pope and co-workers [9] synthesized a series of trimetallo derivatives SiW 9 M 3 of both α-and β isomers with M = Cr III , Fe III , Mn II , Co II , Ni II and Cu II , but failed to get X-ray quality single crystals, and hence the magnetic properties were not analyzed in relation with the structural information.…”

“…SiW 9 O 34 ] (2). This compound exhibits strong antiferromagnetic interaction between the spin carriers of the Mn mixedvalent trinuclear moiety, which suggests an S = 5/2 ground state.…”

“…Considering the importance of these tri-substituted Keggin POMs as a model for soluble catalytic metal oxide surfaces [9] and the possibility of tuning the spin-exchange behaviour within the substituted transition-metal complexes [10] we felt the need to find rational synthetic procedures to obtain tri-substituted POMs with mixed-valent metal environments. Therefore, a novel strategy was adopted by considering a suitable manganese precursor containing a trinuclear mixed-valent [Mn II Mn III 2 ] complex, [Mn 3 (μ 3 -O)(2-Cl-benzoato) 6 (py) 3 ] (1, with py = pyridine), [11] that could eventually occupy the three vacant sites of the lacunary silicotungstate precursor Na 10 [A-α-SiW 9 O 34 ] (2) and ultimately build up the transition-metal substituted Keggin polyanion (3) (Scheme 1).…”

A Novel Inorganic‐Organic Composite Constructed from Cobalt(II)‐Monosubstituted Polyoxometalates and Poly(amidoamine)‐NH2 Dendrimers

“…2,3 An important subclass of POM clusters is lacunary POM, which misses one or more addenda atoms (W, Mo). Unsaturated POM can bind several different transition metals 4,5 to form transition-metal-substituted polyoxometalates (TMSP). The Keggin anion [Co II (H 2 O)PW 11 O 39 ] 5- (Figure 1) is an example of the monosubstituted polyoxometalates, in which the transition metal Co(II) was coordinated by five formal O atoms of [PW 11 O 39 ] 11-while the last coordinate site was occupied by H 2 O.…”