European Journal of Inorganic Chemistry最新文献

A tridentate trimethylstannyl substituted alkyne based on the tribenzotriquinacene (TBTQ) scaffold has been transformed into several gold(I)phosphane complexes by tin-gold exchange. While the molecular structures of the gold(I) derivatives with less bulky trimethyl and dimethylphenylphosphane ligands exhibit intermolecular aurophilic interactions, the sterically demanding triphenylphosphane ligands inhibit the occurrence of Au⋅⋅⋅Au contacts. In addition, a hexanuclear gold(I) system was synthesised by terminal functionalisation of the hexaalkynyl TBTQ. Investigations of the photophysical properties of the gold(I)phosphane TBTQ compounds revealed their luminescent character at room temperature.

The Cover Feature illustrates the integration of a 3D porous polymer and its interaction with Congo Red molecules, highlighting the polymer′s efficient dye adsorption. The large cube represents a polymer network, with red and blue bonds indicating molecular bonds between different monomers. Floating chemical structures depict Congo Red dissolved in an aqueous solution with its adsorption into the material leading to a clearer background. More information can be found in the Research Article by N. Yang, R. Kunthom and H. Liu.

The serious mismatch between the positive and negative electrodes of supercapacitors (SCs) makes it imperative to develop high-performance negative electrode materials. Among them, multimetallic iron-based oxides (MIBOs) are intensively investigated attributed to their high theoretical specific capacitance, wide operating potential window, copious electrochemical active sites, variable metal oxidation states, and abundant redox centers. This paper briefly introduces some essential information on SCs and the most common synthesis methods of MIBOs. Also, the research progress of several important MIBOs and their composites is discussed. Finally, the existing problems and challenges of MIBOs are summarized and future outlooks are likewise proposed.

Chemical reduction of a dinuclear [(di-NHC)Au₂Cl₂(di-NHC)] complex (NHC=imidazol-2-ylidene), using excess NaBH₄ as reducing agent in presence of dichloromethane (DCM) as solvent, provides a molecular cluster with formula [Au₁₃(di-NHC)₅(CH₃)₂]Cl₃, exhibiting covalent bonds between gold atoms of the cluster core and methyl groups. The presence of Au-CH₃ bonds, which is unprecedented in gold cluster chemistry, is confirmed by high resolution mass spectrometry (HRMS), NMR and the reactivity of the reported cluster in solid state. The cluster has been further characterized with single crystal X-ray diffractometry, UV-Vis and emission spectroscopies. The cluster displays remarkable stability in solution, which is indicative of the possible role played by Au-CH₃ bond formation in the conventional preparation of molecular gold nanoclusters by reduction with excess borohydride in DCM.

Hydrochars synthesized from lignocellulosic waste (rice husk and exhausted black wattle bark) through hydrothermal carbonization were used as pore-forming agents in template-free ZSM-5 zeolites. The influence of the amount of hydrochar added to the zeolite synthesis and the nature of the hydrochar on the zeolite features and catalytic performance were evaluated. It was observed that the hydrochar had little influence on the textural properties and Si/Al ratio of the zeolites. However, the hydrochar was able to enhance the number of Brønsted acid sites in the zeolite and led to different ZSM-5 crystal morphologies (french-fries and twinned crystals). The latter zeolites exhibited a higher cracking activity of n-hexane, favoring the formation of light olefins, due to the presence of Brønsted sites and suitable shape selectivity. In contrast, they exhibited a lower conversion of methanol into hydrocarbons (MTH), favoring the formation of dimethylether due to rapid deactivation. The hydrochars acted therefore, in the synthesis of template-free ZSM-5 zeolite, as a mean to both raise the acidity and control the aggregation of zeolite crystals.

The bistability of spin-transition materials is the origin of their multifunctional properties. It causes hysteresis phenomena, i. e., relaxation from a metastable state, of the spin (electronic) state, magnetization, etc. The collapse of a strong metastable state is a long-time relaxation phenomenon. To study such nonequilibrium dynamical phenomenon, time evolution dynamics analyses are important. However, it is difficult to estimate long-time relaxation phenomena by studying time evolution dynamics simulations due to the limitation of the simulation time. Furthermore, because the relaxation occurs in a stochastic process, a wide distribution of the relaxation time has to be considered in the analysis of the relaxation. To overcome these difficulties, we recently developed two methods for the quantitative estimation of the relaxation time from a metastable magnetic state and of the coercive field. In the first method, the relaxation time and coercive field are estimated using the survival (unrelaxed) probability of the ensemble of systems at each field, which extends the limitation of the simulation time. In the second method, they are estimated from the field-dependent free energy barrier obtained from the survival probability under a sweeping field. These methods are applicable to the estimation of the relaxation time and coercive field of any magnetic particles. In this paper, staring with the Stoner–Wohlfarth model, the difference in the characteristic features of the magnetization reversal dynamics between zero and finite temperatures is discussed. Then, the methods of quantitative estimation of the coercive field and relaxation time are presented. The estimation of them using a neodymium permanent magnet grain was demonstrated with the two methods, and the methodological features and the validity of the estimation were discussed. The present study has a common theme to general metastable states including spin transitions.

The phenomenon which is called spin crossover is known to occur in some coordination compounds with an octahedral ligand field and electron configurations from 3d⁴ to 3d⁷. Thereby, a reversible transition between spin states (high spin and low spin state) is possible, through several external stimuli. Iron(II) triazole complexes exhibit this phenomenon at a wide range of temperatures depending on the ligands and anions used. For this reason, they are often considered for several possible practical applications. It is also possible to combine ligands or anions to modify the transition temperature. The latter of which was rarely discussed in the past. In this study we synthesized a series of iron(II)-4-Aminotriazole complexes, with different ratios of chloride- and tetrafluoroborate-anions, of the formula [Fe(Atrz)₃]Cl_2−X(BF₄)_X. We show that the combination of these anions leads to transition temperatures between those of their corresponding pure anion complexes. We furthermore present that a simple modification of the synthesis leads to a possible easy way of fine-tuning transitions temperatures.

In this study, we designed and prepared polyoxometalate@metal-organic framework (POM@MOF) composite catalysts through the anchoring of a sandwich POM [(PW₉O₃₄)₂Co₄(H₂O)₂]¹⁰⁻ (shortened as P₂W₁₈Co₄) to the hexagonal channel of the PCN-222 (metal-free) or PCN-222(M) (M=Fe, Co) frameworks. The composite materials were applied to the electrocatalytic reduction of CO₂ reaction (CO₂RR) to analyse the effect of incorporating P₂W₁₈Co₄ on catalytic activity. The P₂W₁₈Co₄@PCN-222 composite exhibited enhanced activity across a wide potential range (−0.60~−0.85 V vs. RHE) and an optimal FE_CO of 72 % at −0.75 V vs. RHE, which was more than double that of PCN-222 (FE_CO=33 %). The current density surpassed that of the PCN-222 precursors by over sixteen times at the same potential. In contrast, the P₂W₁₈Co₄@PCN-222(M) composite demonstrated decreased current density, minimal enhancement in CO₂RR activity, and a competing HER behaviour. Density functional theory calculations were conducted on simplified models of P₂W₁₈Co₄@H₂-TCPP and P₂W₁₈Co₄@M-TCPP to elucidate the divergent catalytic performances. The findings revealed that while both configurations exhibited the same rate-limiting step (formation of the *COOH intermediate), a significantly reduced reaction barrier was only observed in the P₂W₁₈Co₄@H₂-TCPP setup, explaining its substantial activity improvement.

The role of solvent-exposed cysteines as reactive sites for bioconjugation with a variety of metal drugs or fluorescent probes is emerging in the use of human H-ferritin (HuHf) as a nanocarrier for targeting various tumor cell lines. Here, we have investigated the role of these residues in controlling the structural stability and ferroxidase activity by analyzing the properties of three variants: C90A, C90AC102A, and C130A. Protein folding and cage assembly were unchanged. Ferroxidase activity was also unaffected, indicating that these cysteines are not involved in either the catalytic activity or the overall iron(II) uptake process. For comparison, activity measurements were also performed on two derivatives involving the solvent-exposed cysteine residues.

A new haloargentate hybrid, [Et-dabco]₂Ag₂Br₄ (1) (Et-dabco⁺=1-Ethyl-1,4-diazabicyclo[2.2.2]octan-1-ium), has been successfully synthesized by a solution diffusion method and characterized using microanalysis, single crystal X-ray diffraction, variable-temperature powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and dielectric spectra. The crystal structure of 1 at 273 K contains one-dimensional (1D) anionic [Ag₂Br₄]²⁻ chains, with the [Et-dabco]⁺ cations embedded in the gaps between the inorganic chains. Hybrid 1 underwent a reversible structural phase transition (SPT) at around 464.5 K on heating, and the Pawley refinement revealed similar crystal structures in the low- and high-temperature phases. The SPT endows 1 with switchable and bistable dielectric properties. Combined with previous studies, it was revealed that the self-assembly of silver halide (AgX) with the lower rotational energy barrier of 1-alkyl-1,4-diazabicyclo[2.2.2]octan-1-ium in solution probably achieves new phase transition materials.