Lithium–sulfur batteries are considered one of the next generation potential candidates for electrochemical energy storage devices owing to their high energy density. However, their practical application presents several challenges that need to be addressed. In this study, a flower-like Fe(OH)3 was obtained using a simple and environmentally friendly one-step injection method, intended to be used as sulfur host in lithium–sulfur batteries. The polar hydroxyl groups in Fe(OH)3 capture free polysulphides in the electrolyte via chemisorption and the unique structure of the material physically entraps polysulphides, thus preventing the shuttle effect. Benefiting from functional group and spatial shape advantages, the resultant S@FH electrode yielded an initial capacity of 1187.6 mAh g−1 at 0.1 C. When the batteries are tested for 100 cycles,the reversible capacity remained at 635.2 mAh g−1 and the coulomb efficiency was nearly 100%.

Our study proved that in the case of Ru(II) complexes the intense ROS generation is mainly responsible for the resulting cytotoxicity. The corresponding Ir(III) complexes trigger simultaneously at least three different cytotoxic pathways i. e., depletion of mitochondrial potential, activation of caspases-dependent apoptosis, and ROS-associated oxidation.

Abstract

Two piano-stool ruthenium(II) complexes Ru(η⁶-p-cymene)Cl₂PPh₂CH₂OH (RuPOH) and Ru(η⁶-p-cymene)Cl₂P(p-OCH₃Ph)₂CH₂OH (RuMPOH) and two half-sandwich iridium(III) complexes Ir(η ⁵-Cp*)Cl₂PPh₂CH₂OH (IrPOH) and Ir(η ⁵-Cp*)Cl₂P(p-OCH₃Ph)₂CH₂OH (IrMPOH) have been studied in terms of potential anticancer activity on previously selected cell line (human lung adenocarcinoma). Based on experimental results obtained in monoculture in vitro model mechanistic considerations on the possible cellular modes of action have been carried out. ICP-MS analysis revealed the higher cellular uptake for less hydrophobic Ir(III) complexes in comparison to the corresponding Ru(II) compounds. Cytometric analysis showed a predominance of apoptosis over the other types of cell death for all complexes. The apoptotic pathway was confirmed by a decrease in mitochondrial membrane potential and the activation of caspases-3/9 for both Ru(II) and Ir(III) complexes. It was concluded that in the case of Ru(II) complexes the intense ROS generation is mainly responsible for the resulting cytotoxicity. The corresponding Ir(III) complexes trigger simultaneously at least three different cytotoxic pathways i. e., depletion of mitochondrial potential, activation of caspases-dependent apoptosis, and ROS-associated oxidation. Thus, it can be assumed that the final accumulation of toxic effects over time via parallel activation of different pathways results in the highest cytotoxicity in vitro exhibited by Ir(III) complexes when compared with Ru(II) complexes.

The cooperative “push-pull” effects of Re^I, Mo⁰, W⁰ complexes and borane Lewis acids on the dinitrogen bond are evaluated in molecular orbital diagrams: we extract electronic design principles in terms of orthogonal σ and π “push-pull” paths that may guide the design of complexes towards the desired thermal, electrochemical or photochemical reactivity of N₂.

Abstract

The sustainable fixation of atmospheric N₂ and its conversion into industrially relevant molecules is one of the major current challenges in chemistry. Besides nitrogen activation with transition metal complexes, a “push-pull” approach that fine-tunes electron density along the N−N bond has shown success recently. The “pushing” is performed by an electron rich entity such as a transition metal complex, and the “pulling” is achieved with an electron acceptor such as a Lewis acid. In this contribution, we explore the electronic structure implications of this approach using the complex trans-[Re^ICl(N₂)(PMe₂Ph)₄] as a starting point. We show that borane Lewis acids exert a pull-effect of increasing strength with increased Lewis acidity via a π-pathway. Furthermore, the ligand trans to dinitrogen can weaken the dinitrogen bond via a σ-pathway. Binding a strong Lewis acid is found to have electronic structure effects potentially relevant for electrochemistry: dinitrogen-dominated molecular orbitals are shifted into advantageous energetic positions for redox activation of the dinitrogen bond. We show how these electronic structure design principles are rooted in cooperative effects of a transition metal complex and a Lewis acid, and that they can be exploited to tailor a complex towards the desired thermal, electrochemical or photochemical reactivity.

Luminescent zinc(II) and paramagnetic copper(II) and manganese(II) complexes have been prepared with unprecedented benzothiadiazolyl−pyridine and −2,2′-bipyridine ligands.

Abstract

Two new luminescent ligands, 4-(2-pyridine)-7-methyl-2,1,3-benzothiadiazole (L¹) and 4-(2,2-bipyridine)-7-methyl-2,1,3-benzothiadiazole (L²), based on 2,1,3-benzothiadiazole and pyridine or bipyridine were obtained by Suzuki coupling reactions. DFT and TD-DFT type calculations have been performed on L¹ and L² in order to assign their experimental UV-visible and emission bands. Reaction of L¹ and L² with metal(II) chlorides (M=Zn, Mn, Cu) provided the neutral complexes of formulas [ZnL¹Cl₂] (1), [Zn(L¹)₂Cl₂] (2), [ZnL²Cl₂] (3), [MnL²Cl₂] ⋅ 0,5CH₂Cl₂ (4) and [CuL²Cl₂] ⋅ H₂O (5) which have been structurally characterized. The Zn(II) ions in 1 and 2 are four-coordinate in somewhat distorted tetrahedral N₂Cl₂ surroundings with L¹ adopting bidentate (1) and monodentate (2) coordination modes. Complexes 3–5 are isostructural and their metal atoms are five-coordinate in distorted square pyramidal environments with three nitrogen atoms from the tridentate L² ligand and a chlorine building the basal plane and another chlorine atom occupying the apical position. The three Zn(II) complexes are strongly luminescent in solution and the solid state, while the cryomagnetic study of the paramagnetic compounds 4 and 5 in the temperature range 2.9–300 K shows a Curie-Weiss behaviour typical of small antiferromagnetic interactions which are mediated by weak intermolecular contacts.

A hydrophobic DES having low density and viscosity based on Thenoyl trifluroacetone (HTTA) and Trioctyl phosphine oxide (TOPO) was shown to extract and partition actinides and lanthanides and used as a medium for dissolution of uranium oxide.

Abstract

Hydrophobic Deep Eutectic Solvents (DESs) have been attracting attention for metal ion extraction in solvent extraction process due to their favorable properties. A Trioctyl phosphine oxide (TOPO) and Thenoyl trifluoroacetone (HTTA) based hydrophobic DES was synthesized and characterized by FTIR and NMR spectroscopy. Actinide ions ( UO₂ ²⁺, Pu⁴⁺ and Am³⁺) and Eu³⁺ ion extraction was carried out using the DES which shows that it extracts these metal ions from aqueous nitric acid medium depending upon the molarity of nitric acid. At higher molarity of nitric acid (>5 M) the extraction becomes insignificant only for trivalent metal ions and open up the possibility to selectively strip trivalent metal ions from tetravalent and hexavalent ions. This DES was also used for dissolution of uranium oxide (UO₃). The dissolution kinetics was studied and it was shown that oxide was dissolved within an hour at 80 °C. The maximum solubility of UO₃ in DES was measured and found to be 130±5 mg/mL which is one of the highest reported solubility of UO₃ in ILs and DES. The species of uranium which is formed in situ in DES was ascertained to be UO₂(TTA)₂.TOPO after dissolution of UO₃ as supported by FTIR and NMR (¹H and ³¹P) investigations.

Luminescent Cu(I) complexes have attracted significant interest due to their adjustable emission properties, diverse structures, and reasonable cost. In this work, two class of complexes, namely phosphinine and pyridine ligated Cu(I) complexes that differ by only one atom, were synthesized and characterized. Photophysical analysis and theoretical studies reveal an emissive phosphinine-localized triplet states for Cu(I) phosphinine complexes, and a temperature-dependent interplay between metal-to-ligand charge-transfer (MLCT) singlet and triplet states for Cu(I) pyridine complexes. In general, the Cu(I) phosphinine complexes exhibit a longer lifetime and greater temperature-dependent lifetime changes than the pyridine complexes. A molecular thermometer incorporating Cu(I) phosphinine complexes 2c as indicator was fabricated. This thermometer exhibits a rare linear correlation between temperature and lifetime ranging from 77–297 K with a high sensitivity of –13.5 μs K–1.

The Cover Feature shows the electrochemical reduction of nitrate and nitrogen for sustainable ammonia synthesis under ambient conditions on a Cu-nanosphere catalyst. The self-supported nanosphere structure of the Cu-nanosphere catalyst accelerates overall electrochemical reactions, while the dominance of the Cu (200) facet of the Cu-nanosphere catalyst suppresses the competing hydrogen evolution reaction (HER). Thus the Cu-nanosphere catalyst exhibits outstanding electrocatalytic activity for NO₃RR and NRR. We would like to celebrate the 45^th anniversary of our Institute of Chemistry. Cover art by Thao Hoang, Toan Nguyen, Nhung Tran. More information can be found in the Research Article by T. T. H. Hoang and co-workers.

The supramolecular crystals show crown-ether ring size dependent crystal structure, phase transition and dielectric properties.

Abstract

Crown ethers demonstrate significant conformational flexibility and rotational symmetry, rendering them invaluable in the realms of supramolecular chemistry and crystal engineering. These unique natures facilitate the construction of supramolecular crystals of crown ethers, characterized by disorder-order phase transitions, imparts unique properties that hold promise for diverse applications across multiple fields. In this study, four supramolecular compounds, namely [Na(15-crown-5)]BF₄ (1), [Na(18-crown-6)]BF₄⋅H₂O (2), [K(15-crown-5)]BF₄ (3) and [K(18-crown-6)]BF₄⋅H₂O (4) were synthesized and characterized by microanalysis, thermogravimetric analysis, differential scanning calorimetry and powder X-ray diffraction techniques. Herein, 15-crown-5 and 18-crown-6 correspond to 1,4,7,10,13-pentaoxacyclopentadecane and 1,4,7,10,13,16-hexaoxacyclooctadecane, respectively. It was observed that the crystal structure, phase transition, and dielectric properties of these supramolecular compounds are significantly influenced by the size of the crown-ether rings. The research extensively discussed the correlation between the coordination mode of metal ions of K⁺ or Na⁺ with crown ethers, the compatibility between metal ions and crown-ether rings in terms of size, and the effects of crown-ether disorder on dielectric permittivity during phase transitions. Our discoveries hold significant implications for the design and development of crown-ether supramolecular functional materials.

Ten ionic manganese(II) complexes of [EMIm]2[MnX2Y2] (EMIm = 1‑ethyl-3-methylimidazolium ion; X, Y = Cl, Br or I) and [BnMIm]2[MnX2Y2] (BnMIm = 1-benzyl-3-methylimidazolium ion; X, Y = Cl, Br or I) types were synthesized and studied in terms of their thermal and photophysical properties. Complexes with [BnMIm]+ cation were found to exhibit higher crystallinity, owing to the aromatic π-stacking, and superior photoluminescent quantum yields, promoted by the increased Mn⋯Mn distance. For complexes with chlorine and bromine ligands efficient tunability of photophysical parameters was demonstrated. Out of all complexes, [BnMIm]2[MnBr4] was found to have the highest photoluminescence quantum yield at room temperature (Φ = 0.59). To highlight the importance of a large Mn⋯Mn distance for achieving high Φ values, a mixed-anion analog of complex [BnMIm]2[MnBr4] was prepared, with the suggested formula of [BnMIm]4[MnBr4]Br2. The latter have shown a significant improvement in d–d absorption efficiency and a reduction in nonradiative deactivation, which led to an outstanding Φ value of 0.97. Finally, the optical band gap of [BnMIm]4[MnBr4]Br2 was estimated to describe its applicability as light-emitting material.

1,2,5-Azadiborolane is introduced as a new building block for BCN hybrid polymers. An attempt to use it as a monomer for a cyclolinear poly(iminoborane), only afforded two B−N coupling events. On the other hand, in combination with a p-phenylene diamine-based co-monomer, we obtained hybrid polymers with an average degree of polymerization exceeding 300.

Abstract

The incorporation of BN units in organic scaffolds by isoelectronic/isosteric substitution of selected CC couples has emerged as an efficient tool to produce new materials with useful properties and functions. The knowledge about BN-doped inorganic–organic hybrid polymers, however, is still rather scarce. This is especially true for linear or cyclolinear macromolecules that feature longer inorganic chains. Herein, we introduce 1,2,5-azadiborolane as a polymer building block for the first time. An attempt to apply it for the synthesis of a cyclolinear poly(iminoborane) resulted after only two B−N coupling events in the formation of a molecular compound comprising a chain of three nitrogen and two boron atoms – as confirmed by single-crystal X-ray diffractometry. In combination with a p-phenylene diamine-based co-monomer, we accomplished to incorporate the 1,2,5-azadiborolane into a hybrid polymer of considerable molecular weight that features a B₂N₃ chain. We additionally synthesized a small molecular model compound for the polymer and characterized it crystallographically as well. Comparison of the UV-vis spectra of the monomer, the oligomer, and the polymer revealed systematic red-shifts of the longest-wavelength absorption band with increasing number of BN units in the chain.