Capture of the Complex [Ni(dto)2]2– (dto2– = Dithiooxalato Ligand) in a Mo12 Ring: Synthesis, Characterizations, and Application toward the Reduction of Protons

Investigation of the unique magnetic behaviours of isomers in a 1,2-dithiooxalato-bridged diiron(II) complex

1,2-Dithiooxalate (dto) can be employed as a bridging ligand and it exhibits symmetric (O,S-chelation) or asymmetric (O,O- and S,S-chelation) coordination forms. In this study, we prepared a novel dto-bridged diiron(II) complex, [{Fe(TPA)}2(μ-dto)](ClO4)2 (1), where TPA is tris(2-pyridylmethyl)amine. Interestingly, the bridging dto ligand exhibited not only the asymmetric form but also a linkage isomer and a diastereomer within the same crystal. Notably, the three isomers of 1 exhibited different magnetic properties, resulting in a multi-step spin crossover behaviour.

A new series of bioactive Mo(V)2O2S2-based thiosemicarbazone complexes: Solution and DFT studies, and antifungal and antioxidant activities

This paper deals with the synthesis, characterization, and studies of biological properties of a series of 5 coordination compounds based on binuclear core [Mo(V)2O2S2]2+ with thiosemicarbazones ligands bearing different substituents on the R1 position of the ligand. The complexes are first studied using MALDI-TOF mass spectrometry and NMR spectroscopy to determine their structures in solution in relation to single-crystal X-Ray diffraction data. In a second part, the antifungal and antioxidative activities are explored and the high potential of these coordination compounds compared to the uncoordinated ligands is demonstrated for these properties. Finally, DFT calculation provides important support to the solution studies by identifying the most stable isomers in each [Mo2O2S2]2+/Ligand system, while the determination of HUMO and LUMO levels is performed to explain the antioxidative properties of these systems.

Tuning the nuclearity of [Mo2O2S2]2+-based assemblies by playing with the degree of flexibility of bis-thiosemicarbazone ligands

[MoV2O₂S₂]²⁺-based thiosemicarbazone complexes appear as very promising molecules for biological applications due to the intrinsic properties of their components. This paper deals with the synthesis and characterization of six coordination complexes obtained by the reaction of [MoV2O₂S₂]²⁺ clusters with bis-thiosemicarbazone ligands that contain flexible or rigid spacers between the two thiosemicarbazone units. Interestingly, structural characterization by single-crystal X-ray diffraction, MALDI-TOF MS technique and NMR spectroscopy revealed that the nuclearity of the complex is controlled by the nature of the spacer between the thiosemicarbazone units. Binuclear complexes, namely [MoV2O₂S₂(L^1-3)], are isolated with flexible spacers while tetranuclear complexes [(MoV2O₂S₂)₂(L^4-6)₂] are formed when the bis-thiosemicarbazone ligands are built on rigid spacers.

Polyoxometalate-based Composite Cluster with Core-Shell Structure: Co4(PW9)2@Graphdiyne as Stable Electrocatalyst for Oxygen Evolution and its Mechanism Research

A composite cluster with core-shell structure which is composed of polyoxometalates (POMs) and graphdiyne (GDY) was synthesized and applied for the electrochemical oxygen evolution reaction (OER). Compared with the original...

Electrochemical properties of the [SiW10O36(M2O2E2)]6− polyoxometalate series (M = Mo(v) or W(v); E = S or O)

New insights about the electrochemical properties of S-containing polyoxometalates. Electrochemical properties of the compounds γ-[SiW₁₀O₃₆(M₂O₂E₂)]⁶⁻ (M = Mo(v) or W(v); E = O²⁻ or S²⁻) in DMF.

Two unusual 3D honeycomb networks based on Wells–Dawson arsenomolybdates with d10 transition-metal-pyrazole connectors

Two unusual 3D honeycomb networks based on Wells–Dawson arsenomolybdates were first reported, which have highly efficient catalytic ability for the degradation of organic dyes under UV irradiation and obvious electrocatalytic activities for the reduction of H₂O₂.

Redox and acidic properties of chalcogenido-substituted mixed-metal polyoxoanions: a DFT study of α-[PW11O39ME]4− (M = Nb, Ta; E = O, S, Se)

Substitution of one O atom by S and Se atoms in POMs enhances the redox and acidic properties.

Discovery of gigantic molecular nanostructures using a flow reaction array as a search engine

The discovery of gigantic molecular nanostructures like coordination and polyoxometalate clusters is extremely time-consuming since a vast combinatorial space needs to be searched, and even a systematic and exhaustive exploration of the available synthetic parameters relies on a great deal of serendipity. Here we present a synthetic methodology that combines a flow reaction array and algorithmic control to give a chemical ‘real-space’ search engine leading to the discovery and isolation of a range of new molecular nanoclusters based on [Mo₂O₂S₂]²⁺-based building blocks with either fourfold (C₄) or fivefold (C₅) symmetry templates and linkers. This engine leads us to isolate six new nanoscale cluster compounds: 1, {Mo₁₀(C₅)}; 2, {Mo₁₄(C₄)₄(C₅)₂}; 3, {Mo₆₀(C₄)₁₀}; 4, {Mo₄₈(C₄)₆}; 5, {Mo₃₄(C₄)₄}; 6, {Mo₁₈(C₄)₉}; in only 200 automated experiments from a parameter space spanning ~5 million possible combinations.

The synthesis of molecular nanostructures often requires the variation of several parameters, such as stoichiometry, pH, counter-ion etc. Here, the authors report a flow reaction array with algorithmic control which is used as a ‘search engine’ to isolate six nanoscale clusters from a massive parameter space.

Tuning the electrocatalytic hydrogen evolution reaction promoted by [Mo2O2S2]-based molybdenum cycles in aqueous medium

We report the syntheses and characterizations, in the solid state and in solution, of three new cyclic polyoxothiomolybdates self-assembled around 2,5-dimethylterephthalate (DMT) and 2,5-bis(trifluoromethyl)terephthalate (DFMT) ligands, namely [Mo12DMT](2-), [Mo12DFMT](2-) and [Mo16DFMT](2-). A series of these two Mo12-compounds completed by the two Mo12-compounds obtained with 2,3,5,6-tetramethylterephthalate and trimesate ligands offer the opportunity to compare their electro-catalytic properties for reduction of protons into hydrogen. The ability of these compounds to promote the reduction of protons into hydrogen in aqueous medium is evidenced and the influence of the embedded ligand is highlighted, thus allowing proposal of a mechanism for the hydrogen evolution reaction catalyzed by these clusters.

Charge Photo-Accumulation and Photocatalytic Hydrogen Evolution Under Visible Light at an Iridium(III)-Photosensitized Polyoxotungstate

Steady-state irradiation under visible light of a covalent Ir(III)-photosensitized polyoxotungstate is reported. In the presence of a sacrificial electron donor, the photolysis leads to the very efficient photoreduction of the polyoxometalate. Successive formation of the one-electron and two-electron reduced species, which are unambiguously identified by comparison with spectroelectrochemical measurements, is observed with a significantly faster rate reaction for the formation of the one-electron reduced species. The kinetics of the photoreduction, which are correlated to the reduction potentials of the polyoxometalate (POM), can be finely tuned by the presence of an acid. Indeed light-driven formation of the two-electron reduced POM is considerably facilitated in the presence of acetic acid. The system is also able to perform photocatalytic hydrogen production under visible light without significant loss of performance over more than 1 week of continuous photolysis and displays higher photocatalytic efficiency than the related multi-component system, outlining the decisive effect of the covalent bonding between the POM and the photosensitizer. This functional and modular system constitutes a promising step for the development of charge photoaccumulation devices and subsequent photoelectrocatalysts for artificial photosynthesis.