Synthesis and Structural Characterization of Isomers of Ru-Substituted Keggin-Type Germanotungstate with dmso Ligand

Photocatalytic Reduction of Nitrobenzene to Aniline by an Intriguing {Ru(C6H6)}-Based Heteropolytungstate

In this paper, we have successfully synthesized a structurally novel heteropolytungstate via coordination of four {Ru(C6H6)} and trivacant {TeW9O33} clusters, formulated as Cs4Na2H2[Te2W20O72(H2O){(C6H6)Ru}4]·12H2O (1). Compound 1 inherited the strong absorption of [Ru(C6H6)Cl2]2 in the visible region and {TeW9O33} in the UV region, providing a good basis for photocatalysis. As expected, compound 1 showed good photocatalytic activity in the visible-light-driven reduction of nitrobenzene using N2H4·H2O as a reductant with a yield of 99.8%, a high turnover number (TON = 330), and a high turnover frequency (TOF = 24 h-1). The cyclic experiment of nitrobenzene reduction indicated that compound 1 was an effective and stable heterogeneous catalyst. Finally, the nitrobenzene reduction pathway was affirmed using condensation with azobenzene as a reaction intermediate based on control experiments.

Binuclear Ru(III)-Containing Polyoxometalate with Efficient Photocatalytic Activity for Oxidative Coupling of Amines to Imines

A novel binuclear ruthenium-based polyoxometalate, K₆H[{Ru₂Cl(H₂O)(CH₃COO)₂}{WO(H₂O)}₂(PW₉O₃₄)₂]·14H₂O (1), was successfully synthesized by the conventional hydrothermal method. Compound 1 was well-characterized by single-crystal X-ray diffraction, X-ray powder diffraction (PXRD), infrared (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), electrospray ionization-mass spectrometry (ESI-MS), thermogravimetric analyses (TGA), and elemental analysis. The structural unit of compound 1 contains two [A-α-PW₉O₃₄]^9- building blocks at the upper and lower positions connected by two W atoms and two Ru atoms, where the W atoms and Ru atoms are arranged in a trapezoidal arrangement and the Ru atoms are bridged by acetic acid. Furthermore, compound 1 features characteristic absorption bands in the visible region, which allows the investigation of its photocatalytic properties in visible light. Under simulated sunlight radiation (λ > 400 nm), compound 1 exhibits high photocatalytic activity and good circularity toward the oxidative coupling of amines to imines at room temperature with O₂ as the sole oxidant.

Lanthanide-Containing 22-Tungsto-2-germanates [Ln(GeW11O39)2]13-: Synthesis, Structure, and Magnetic Properties

We report on the synthesis and structural characterization of two series of lanthanide-containing 22-tungsto-2-germanates. The first series corresponds to a family of polyanions with the formula [Ln(β₂-GeW₁₁O₃₉)₂]^13- (Ln^III = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Gd (6), Dy (7)), and the second series corresponds to a family with the formula [Ln(β₂-GeW₁₁O₃₉)(α-GeW₁₁O₃₉)]^13- (Ln^III = Ho (8), Er (9), Tm (10)). All compounds were characterized in the solid state by single-crystal and powder XRD, IR, TGA, and SQUID magnetometry. The polyanions were synthesized in aqueous medium by direct reaction of the monolacunary [β₂-GeW₁₁O₃₉]^8- POM precursor with the corresponding lanthanide salts. The structure of the polyanions consists of an 8-coordinated lanthanide ion in a square-antiprismatic geometry, which is sandwiched either between two [β₂-GeW₁₁O₃₉]^8- units for 1-7 or between a [β₂-GeW₁₁O₃₉]^8- and a [α-GeW₁₁O₃₉]^8- unit for 8-10. Furthermore, the effect of the central paramagnetic lanthanide ion on the magnetic behavior of the polyanions was investigated, with the erbium-derivative [Er(β₂-GeW₁₁O₃₉)(α-GeW₁₁O₃₉)]^13- (9) showing single-molecule magnet (SMM) behavior.