Controlled Assembly of a Dawson-like Antimoniotungstate-Supported Trefoil-type Trimer with Good Proton Conductivity Performance.

With the excellent properties of POM in the field of proton conductivity, the preparation of POM-based proton-conductive materials has burst into life. Herein, an unprecedented Sb-templated all-inorganic trimer Na8H18.64[(SbW14O52)3(Sb2W6.12Ru5.88O18)]·85H2O (1), which is based on tetravacant Dawson-like [SbW14O52]17- blocks and exhibits a trefoil type with D3 symmetry, has been successfully designed and synthesized by the assembly of simple materials with a one-pot hydrothermal method under acidic conditions. Also, compound 1 is systematically characterized by single-crystal X-ray diffraction, PXRD, ESI-MS, IR spectroscopy, UV-vis, elemental analysis, and TGA. Crystal structure data analysis demonstrates that compound 1 is constructed by a hexagonal prismatic heterometallic {Sb2W6.12Ru5.88O18} core and three equivalent {SbW14} units bridged through µ2-O atoms in periphery. Subsequently, further property experiments show that compound 1 exhibits high proton conductivity with a conductivity value (σ) of 3.07 × 10-2 S cm-1 at 75 °C and 80% relative humidity (RH). The activation energy of compound 1 evaluated by the Arrhenius plots is 0.22 eV, which indicates that the Grotthuss mechanism is dominant during the process of proton transfer.

A Hexameric Ruthenium(III)-Containing Tungstoantimonate with Good Proton Conductivity Performance.

A novel Ru(III)-containing tungstoantimonate Na16H22[(B-ß-SbW9O33)6(W3RuO7)2(W4O11)]·118H2O (1) hexamer was successfully synthesized using the hydrothermal synthesis method. Analysis by single-crystal X-ray diffraction revealed that the polyanion comprises six trivacant Keggin-type [B-ß-SbW9O33]9- units interconnected by six {WO6} and six Ru/W disorder octahedra, resulting in an intriguing cyclohexane boat-like conformation. Compound 1 exhibits favorable proton conductivity, with a measured conductivity (σ) of 5.41 × 10-3 S cm-1 at 333 K and 55% relative humidity (RH). The activation energy (Ea) of compound 1 was determined to be 0.40 eV, providing evidence that its proton conductivity conforms to the Grotthus mechanism.

N-N-Bridged Polynuclear POM-Based Coordination Polymers Based on a V-Type Ligand: Proton Conduction and Magnetism.

The construction of polyoxometalate (POM)-based coordination polymers, in the presence of a nitrogen heterocyclic ligand, is intriguing due to the potential for obtaining diverse structures. These structures exhibit extensive application possibilities in the fields of proton conductivity and magnetism. Herein, four new POM-based polynuclear coordination polymers with the formulas of {[Fe2(btb)3(H2O)2(SiW12O40)]·3H2O}n (1), {[Cd2(btb)2(H2O)6(HPMoVI10MoV2O40)]·2H2O}n (2), {[Co3(OH)2(btb)2(H2O)5(HPMoVI10MoV2O40)]·7H2O}n (3), and {[Cu3(OH)(btb)2(H2O)(HP2Mo5O23)]·6H2O}n (4) have been prepared using the V-type 1,3-bis(4H-1,2,4-triazole-4-yl)benzene (btb) ligand. Compounds 1 and 2 feature similar two-dimensional (2D) structures, derived from the binuclear Fe2N6 and Cd2N4 subunits connected by tridentate btb ligands. Meanwhile, in compound 3, hexanuclear Co6(OH)4 units are bound by quadridentate btb ligands forming a 2D layer with the same 4-c sql topology simplification as compounds 1 and 2. In compound 1, Keggin-type polyoxoanions are monodentate-coordinated to metal ions and suspended on the 2D structure, while, in compounds 2 and 3, they act as discrete counterions residing in the interstitial spaces between two adjacent layers, thereby extending the 2D structures into 3D structures through hydrogen bonding interactions. In compound 4, trinuclear Cu3(OH) subunits are further constructed into a 3D framework through cooperation with four tridentate and quadridentate btb ligands as well as Strandberg-type anions. Furthermore, the proton conduction of the four compounds has been investigated. They display high proton conductivities at 358 K and 98% RH with powdered samples, which are 1.26 × 10-3, 1.24 × 10-3, 3.24 × 10-4, and 2.57 × 10-4 S cm-1, respectively. Interestingly, by mixing with Nafion, the composite membranes of compounds 2 and 4 exhibit enhanced proton conductivities, measuring at 4.87 × 10-2 and 1.28 × 10-2 S cm-1, respectively, at 358 K and 98% RH, which suggests excellent potential for applications. In addition, compounds 1, 3, and 4 display antiferromagnetic behaviors due to similar magnetic interactions. This work can provide research insights into the assembly of 2D POM-based coordination polymers with nitrogen heterocyclic ligands and Keggin-type POMs and further promote their research progress in proton conduction.

Characterization and Phylogenetic Analysis of the Complete Mitochondrial Genome of Saturnia japonica.

The complete mitochondrial genome (mitogenome) of Saturnia japonica (Lepidoptera: Saturniidae) was sequenced and annotated. It is a circular molecule of 15, 376 bp, composed of 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNA), and an adenine (A) + thymine (T)-rich region. All protein-coding genes (PCGs) are initiated by the ATN codon except for cytochrome c oxidase subunit 1 (cox1) gene that is seemingly initiated by the CGA codon. Except for cox2 and nad4, which were terminated by incomplete stop codon T or TA, the rest were terminated by canonical stop codon TAA. The A + T-rich region is high conservative, including 'ATAGA' motif followed by a 19 bp poly-T stretch, a microsatellite-like element (AT)9 and also a poly-A element, with a total length of 332 bp. The Asn codon was the most frequently used codon, followed by Ile, Leu2, Lys, Met, Phe, and Tyr, while Cys was the least frequently used codon. Phylogenetic relationships analysis based on the 13 PCGs by using maximum likelihood (ML) and neighbor Joining (NJ) revealed that S. japonica belongs to the Saturniidae family. In this study, the annotation and characteristics of the mitogenome of S. japonica were resolved for the first time, which laid a foundation for species classification and the molecular evolution of Lepidoptera: Saturniidae.