Robust, Alkali-Stable, Triscarbonyl Metal Derivatives of Hexametalate Anions, [M6O19{M‘(CO)3}n](8-n)- (M = Nb, Ta; M‘ = Mn, Re; n = 1, 2)

Theoretical studies on tricarbonyl metal derivatives of Lindqvist-type polyoxometalate complexes: electronic structures and nonlinear optical properties

The β₀ value of tricarbonyl metal derivatives of a Lindqvist-type polyoxometalate depends on the tricarbonyl metal M. [Nb₂W₄O₁₉Ru(CO)₃]²⁻ has the largest hyperpolarizability, 12.456 × 10⁻³⁰ esu, and might become an excellent NLO material.

Synthesis, crystal structure and photocatalytic properties of an unprecedented arsenic-disubstituted Lindqvist-type peroxopolyoxoniobate ion: {As2Nb4(O2)4O14H1.5}4.5−

An unprecedented arsenic-disubstituted Lindqvist-type ion {As₂Nb₄(O₂)₄O₁₄H_1.5}^4.5− which shows a certain photocatalytic water splitting activity has been successfully synthesized and characterized.

A monovacant heteropolytungstate-incorporated trimeric carbonyl rhenium cluster, [(AsW11O39){Re(CO)3}3(μ3-OH)(μ2-OH)]6−: synthesis, structure and catalytic properties

The novel undecatungstoarsenate-supported carbonyl rhenium derivative exhibits prominent catalytic activity and high selectivity in the cycloaddition of epoxides.

Complexation of metal carbonyl units with [α-PW11O39]7− and [α2-P2W17O61]10−: insights into the chiral “twisted-sandwich” dimeric structures

Capturing [M(CO)₃]⁺ (M = Re, Mn) by [α-PW₁₁O₃₉]⁷⁻ or [α₂-P₂W₁₇O₆₁]¹⁰⁻ leads to polyoxometalate-supported metal carbonyl complexes with chiral “twisted-sandwich” structures.

An inorganic chromophore based on a molecular oxide supported metal carbonyl cluster: [P2W17O61{Re(CO)3}3{ORb(H2O)}(μ3-OH)]9-

A polyoxometalate-supported trirhenium carbonyl cluster, mimicking metal oxide supported interfacial dyadic structures, has been synthesized and characterized. Multiple techniques, including computational and transient absorption spectroscopy, have been applied to characterize the charge-transfer dynamics occurring at the interfaces of this "double cluster". The stepwise kinetics of charge separation and recombination has been thoroughly investigated.

A decatungstate-type polyoxoniobate with centered manganese: [H2Mn(IV)Nb10O32]8- as a soluble tetramethylammonium salt

A highly symmetric Mn(IV)-centered polyoxoniobate [H2Mn(IV)Nb10O32](8-) was synthesized via hydrothermal methods as a soluble tetramethylammonium salt. The structure is similar to decatungstate structure [W10O32](4-), except for the central heteroatom. The cluster is stable between 4 < pH < 10, as was characterized with ESI-MS and UV-Vis spectroscopy.

An 17O NMR Study of Hydrolyzed Nb(V) in Weakly Acidic and Basic Aqueous Solution

Time-dependent ¹⁷O NMR spectra of basified decaniobate (Nb₁₀O₂₈^6-) solutions displayed intense resonances assigned to the well-known protonated hexaniobate anion (Nb₆O₁₉^8-) and two other species identified as heptaniobate (Nb₇O₂₂^9-) and protonated tetracosaniobate (Nb₂₄O₇₂^24-) anions. The decaniobate ion showed no sign of protonation from pH 6 - 10, in contrast with the hexaniobate ion which was protonated at doubly-bridging oxygen sites at pH 10-13. Most (> 90%) of the heptaniobate formed 1 h after basification was transformed into other species after 3 weeks. Tetracosaniobate was formed reversibly from decaniobate, but only when KOH, NaOH and [(CH₃)₄N]OH were employed; none was observed after basification with [(n-C₄H₉)₄N]OH. Moreover, far more tetracosaniobate was formed from KOH than from [(CH₃)₄N]OH. This effect was attributed to a tetracosaniobate cation binding site that binds K⁺ more readily than (CH₃)₄N⁺ but is too small to accommodate (n-C₄H₉)₄N⁺.

A comprehensive comparison of transition-metal and actinyl polyoxometalates

While the d(0) transition-metal POMs of Group V (V(5+), Nb(5+), Ta(5+)) and Group VI (Mo(6+), W(6+)) have been known for more than a century, the actinyl peroxide POMs, specifically those built of uranyl triperoxide or uranyl dihydroxidediperoxide polyhedra, were only realized within the last decade. While virtually every metal on the Periodic Table can form discrete clusters of some type, the actinyls are the only-in addition to the transition-metal POMs- whose chemistry is dictated by the prevalence of the 'yl' oxygen ligand. Thus this emerging structural, solution, and computational chemistry of actinide POMs warrants comparison to the mature chemistry of transition-metal POMs. This assessment between the transition-metal POMs and actinyl POMs (uranyl peroxide POMs, specifically) has provided much insight to the similarities and differences between these two chemistries. We further break down the comparison between the alkaline POMs of Nb and Ta; and the acidic POMs of V, Mo and W. This more indepth literature review and discussion reveals that while an initial evaluation suggests the actinyl POMs are more akin to the alkaline transition-metal POMs, they actually share characteristics unique to the acidic POMs as well. This tutorial review is meant to provide fodder for deriving new POM chemistries of both the familiar transition-metals and the emerging actinides, as well as fostering communication and collaboration between the two scientific communities.

Synthesis and characterization of a metal-to-polyoxometalate charge transfer molecular chromophore

[P(4)W(35)O(124){Re(CO)(3)}(2)](16-) (1), a Wells-Dawson [α(2)-P(2)W(17)O(61)](10-) polyoxometalate (POM)-supported [Re(CO)(3)](+) complex containing covalent W(VI)-O-Re(I) bonds has been synthesized and characterized by several methods, including X-ray crystallography. This complex shows a high visible absorptivity (ε(470 nm) = 4000 M(-1) cm(-1) in water) due to the formation of a Re(I)-to-POM charge transfer (MPCT) band. The complex was investigated by computational modeling and transient absorption measurements in the visible and mid-IR regions. Optical excitation of the MPCT transition results in instantaneous (<50 fs) electron transfer from the Re(I) center to the POM ligand.