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CrystEngCommrsc. li/ crystengcomm ISSN 1466- 8033 Volume 26 Number 18 14 May 2024 Pages 2335– 2442 PAPER Juan Olguín et al. Nitro group and K+- based secondary building units for the self- assembly of 3D coordination polymers built on dinuclear dianionic helicate connectors Environmental Science: Atmospheres Connecting communities and inspiring new ideas rsc. li/ submittoEA Fundamental questions Elemental answers GOLD OPEN ACCESS Registered charity number: 207890 [Extracted from the article]

The document is a contents list for the journal CrystEngComm. It highlights various papers and communications published in the journal, including topics such as hydrogen storage, coordination polymers, luminescent sensors, and chemical solution deposition. The cover image features the Tembleque Aqueduct World Heritage Site in Mexico. The journal is published by the Royal Society of Chemistry, a leading chemistry community that connects the world with the chemical sciences. [Extracted from the article]

Multiple hydrogen bonds construct a porous crystalline network, known as a hydrogen-bonded organic framework (HOF). Although hydrogen bonds have relatively weak bond strength compared to covalent bonds, they contribute to the structural flexibility of HOFs. This flexibility sometimes manifests as an S-shaped isotherm, providing a high gas working capacity crucial for effective gas storage. Despite the recognized potential of HOFs, there are limited examples of gas storage under high pressure to date. Herein, we report the synthesis and hydrogen gas storage properties of HOF 1 ([(H2dobpdc)(GuaH)2]) for the first time. This framework, constructed through multiple hydrogen bonds, exhibits excellent structural stability over one year and selective hydrogen gas adsorption and storage based on its structural flexibility. [ABSTRACT FROM AUTHOR]

Two 3D coordination polymers based on dinuclear dianionic helicates, K2[MII2(L)3] M = MnII (1) and NiII (2), were obtained by slow liquid–liquid diffusion of solutions of 2-hydroxy-5-nitrobenzaldehyde, 4,4′-methylenedianiline, KOtBu and the metal salt at room temperature. The resulting dianionic triply stranded helicates self-assemble into novel 3D coordination polymers, in which the helicate units act as connectors. The assembly is promoted by the phenolate bridging ability and the coordination of the pre-organized NO2 groups to K–(O–N–O)4–K nodes, resulting in robust paramagnetic materials. SC-XRD shows that the metal centers are located 11.257(2) and 11.264(1) Å apart. The Mn–L bond lengths correspond to the high-spin (HS, S = 5/2) state for 1. The magnetic behavior for both complexes shows weak magnetic exchange, as expected due to the spin carrier separation, and the confirmation of the HS-sate for the MnII centers. For complex 1, an antiferromagnetic exchange is detected, whereas for complex 2, a mixture of intramolecular antiferromagnetic and intermolecular ferromagnetic exchanges are detected. Thus, we demonstrated that nitro groups can be used for the stabilization of anionic complexes because coordination to K+ results in stable intricate architectures. [ABSTRACT FROM AUTHOR]

Coordination polymers (CPs) with a d10-configuration containing metal cations offer interesting photoluminescent properties and hence can be employed as sensors to detect various classes of analytes. Moreover, due to their tuneable pore size they can be employed as adsorbents for various species. Herein, a new d10-configuration Cd(II)-based CP with composition {[Cd(bip)4(H2O)2]n·2NO3} (1) (bip = 3,5-bis(1-imidazol)pyridine) has been synthesized and characterized. Single-crystal X-ray analysis reveals that the Cd(II) center adopts octahedral geometry that is satisfied by four N atoms from the four bip linkers and two aqua ligands, and the resultant CP displays sql topology with the point symbol of (44·62). The CP offers prospective application as a photoluminescent sensor for dichromate anions with a limit of detection of 1.28 ppm and a Stern–Volmer constant (KSV) of 1.51 × 105. Furthermore, CP 1 was employed as an efficient adsorbent for dichromate ions, reaching an equilibrium adsorption capacity of 389.82 mg g−1 within 80 min. The effects of temperature, pH and concentration of dichromate were further investigated, which revealed that CP 1 displays the best adsorption at 30 °C and pH 4 with a dichromate concentration of 200 mg L−1. The possible adsorption mechanism has been proposed with the aid of Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

Inter-molecular π–π stacking interactions of aromatic systems play crucial roles in functional nanomaterials and therapeutics. Herein, we developed a series of novel 8-hydroxyquinoline-polycyclic aromatic hydrocarbon (PAH) conjugates (PH1–PH3) by coupling 8-hydroxyquinoline with a series of PAHs such as naphthalene, anthracene, and pyrene. A second series of quinoline-PAH derivatives (PD1–PD3) has also been developed by sulfonating the quinoline –OH of the first series. Crystallographic analyses of these compounds revealed exciting structural and supramolecular features. Supramolecular analyses of PH series compounds revealed that the crystal packing interactions in these compounds are dominated by intermolecular C–H⋯O and C–H⋯π interactions, in which the C–H⋯O interactions lead to the formation of zig-zag 1D chains in the crystal lattice, which are interconnected to a 3D network by various intermolecular C–H⋯π interactions. Compared to the PH series, the supramolecular interactions in the PD series are dominated by π–π and C–H⋯π interactions. In these compounds, two adjacent V-shaped molecules are arranged in a dimeric fashion such that one arm of the V-shaped molecule is packed within the cleft formed by the arms of the other. In the crystal lattice of PD series compounds, such dimers are interconnected through π–π interactions into 1D chains/2D sheets, which are further interconnected into 2D/3D networks through additional C–H⋯π/π–π stacking interactions. The preliminary cytotoxicity properties of PH and PD series compounds were evaluated using human hepatocellular carcinoma cells (HepG2 cells). It was observed that the presence/absence of –OH group on the quinoline ring and the size of the PAH ring play significant roles in determining the cytotoxicity of these compounds. The PH series compounds with an –OH substituent on the quinoline ring exhibited comparatively better cytotoxicity (IC50 values in the range 8.03–11.72 μM) than the PD series compounds (IC50 values in the range 9.48–38.16 μM) with sulfonated quinoline moiety. The compound bearing pyrene PAH and –OH substituent on the quinoline ring exhibited the best cytotoxicity (IC50 = 8.03 μM) among all the compounds tested. The present study, therefore, shows that the quinoline-PAH conjugates can exhibit interesting structural and supramolecular properties along with appreciable cytotoxic effects. Further, these properties could be fine-tuned by changing the size of the PAH ring and the substituent on the quinoline ring. [ABSTRACT FROM AUTHOR]

Traditional chemical solution deposition (CSD) methods for growing Ga2O3 films face two main issues: limited thickness per deposition, necessitating multiple coating-annealing cycles for adequate film thickness, and a decline in crystal quality with increased thickness. This study introduces an innovative CSD technique for fabricating (GaAl)2O3 films, achieving both high thickness and superior crystal quality, where the aluminum content results from the diffusion of aluminum from sapphire substrates during annealing. The technique uses a precursor solution with high viscosity and cation concentration, allowing single-layer thicknesses of up to 180 nm. Additionally, the incorporation of silver nitrate for silver doping enhances nucleation, growth, and epitaxial quality, inducing a unique twelve-fold symmetry in the (−201) oriented (GaAl)2O3 films. Notably, silver serves as a catalyst and largely evaporates at high temperatures, thus preserving the film's final composition and performance. This study highlights the effectiveness of this CSD approach in simultaneously improving crystal quality and achieving desired film thickness, making it a promising method for mass production of high-quality (GaAl)2O3 films. [ABSTRACT FROM AUTHOR]

Herein, we used a hydrothermal method and calcination at different temperatures to synthesize Ca2Nb2O7 composite oxides with two different sub-crystalline phases, namely perovskite and pyrochlore. From the photocatalytic degradation of tetracycline, the catalytic activity of the pyrochlore crystalline phase is higher than that of the perovskite crystalline phase. This is because the pyrochlore phase structure is more disordered, which has abundant oxygen vacancies and can generate more ·O2−, h+, and ·OH under visible light irradiation. Additionally, it has a smaller bandgap and a lower valence band energy. The combination of these factors enables the higher reaction activity of the pyrochlore phase structure compared with the perovskite crystalline phase. [ABSTRACT FROM AUTHOR]

New nanostructures betokening new nanotechnology and nanoscience. In this work, novel one-dimensional (1D) Y2(Zr0.6Ti0.4)2O7:Eu tube-in-tube nanostructures were fabricated by a simple single-nozzle electrospinning method. The Y2(Zr0.6Ti0.4)2O7:Eu double-layered nanotube consisted of an outer tube with a diameter of 250–340 nm and an inner tube with a diameter of 80–110 nm. The wall thickness of the outer tube is ∼30 nm. The wall thickness of the inner tube is ∼25 nm. The key to this technique is to utilize the difference in hydrolysis rates between the titanium source and the zirconium source in an air atmosphere with a humidity of 40–45% to obtain nanoscale tube-in-tube structures. The Y2(Zr0.6Ti0.4)2O7:Eu tube-in-tube nanostructures exhibit excellent luminescence stability and lower color drift performance at high temperatures. [ABSTRACT FROM AUTHOR]

Non-additive factors can significantly affect the crystallization pathways and hydrate phases of calcium oxalate. However, little is known about the mechanisms behind these phenomena. Our research investigated various factors affecting calcium oxalate crystallization in the absence of additives. We show that the formation of calcium oxalate hydrate phase in a supersaturated solution is inconsistent with thermodynamic stability. The metastable calcium oxalate trihydrate (COT) forms at lower concentrations (<1.25 mM), while the stable calcium oxalate monohydrate (COM) forms at intermediate concentrations, and the metastable calcium oxalate dihydrate (COD) forms at higher concentrations (>20 mM). The formation of the hydrate phase also depends on the method of mixing calcium and oxalate solutions. By utilizing an automatic titration apparatus, we show that the hydrate phase can be altered by adjusting either the titration rate of the calcium solution or the stirring speed. In addition, the calcium-to-oxalate ratio is important in determining the initial binding between calcium and oxalate ions. All these factors could be explained by the local concentration of calcium and oxalate upon mixing the solutions. The reduction of local concentration promotes the formation of COT. Thus, the hydrate phase is determined by a combination of thermodynamic and kinetic factors. These results significantly enhance our understanding of the crystallization pathway and hydrate phase selection of calcium oxalate. [ABSTRACT FROM AUTHOR]

In recent years, the development of new scintillation materials with red and near-infrared light emission has had significant advantages based on the development of an avalanche photodiode with high quantum yield. This study used a hydrothermal method to synthesize rare-earth-doped Cs2NaScCl6 crystals, in which a red emission of Cs2NaScCl6:Sm was investigated with high X-ray sensitivity and low detection limit. In addition, a tunable wavelength range of radioluminescence can be achieved, in which a near-white light emission can be generated by precisely controlling the proportion of Sm3+ and Tb3+ doping concentrations. Meanwhile, a Cs2NaScCl6:7%Sm scintillation film has been successfully prepared by direct coating with a thickness of 150 μm, which achieves a spatial resolution of 11.9 lp mm−1 based on X-ray imaging experiments. Therefore, this perovskite material has shown potential application as an eco-friendly multifunctional imaging material. [ABSTRACT FROM AUTHOR]

Zinc metal–organic frameworks (Zn-MOFs) of phthalic acid (ZnPA) and nitro-phthalic acid (ZnNPA) microcrystalline particles were fabricated and utilized for the removal of organic cationic dyes (crystal violet (CV), methylene blue (MB) and rhodamine B (RhB)) from water. PXRD studies confirmed the formation of crystalline materials, and BET indicated the mesoporous structure. HR-SEM studies showed the rod and plate morphologies for ZnPA and ZnNPA, respectively. ZnPA revealed low adsorption of dyes (CV, 20%) whereas ZnNPA showed significantly enhanced dye adsorption (CV, 99%). In particular, ZnNPA exhibited higher adsorption of CV (99%) and MB dye (83%) compared to RhB (54%). Nevertheless, ZnNPA could not be reused due to strong adsorption of dyes. Hence, a natural binder was introduced by dipping ZnNPA into tea extract, which also showed high adsorption of CV and MB dyes. Kinetics of adsorption exhibited best fitting with the pseudo-second-order model, indicating strong interactions between the dyes and adsorbent. Adsorption isotherm fitting suggested a good correlation coefficient (R2) with the Freundlich model, suggesting multi-layer adsorption. Interestingly, ZnNPA showed high adsorption of CV and MB dyes across the pH range between 3.0 and 11.0. The binder-introduced ZnNPA adsorbent was easily regenerated and demonstrated three cycles of reusability without significant change in the dye adsorption. Thus, the present work indicated the role of functional groups in the ligand and binder for improving the dye adsorption characteristics of MOFs. [ABSTRACT FROM AUTHOR]

Two 5-nitroisophthalate (NIPA) based cobalt(II) coordination polymers [Co(4-ABPT)(NIPA)(H2O)3], SSICG-6 (4-ABPT = 3,5-di(pyridine-4-yl)-4H-1,2,4-triazol-4-amine, SSICG stands for solid-state and inorganic chemistry group) and [Co(4-ABPT)(NIPA)(H2O)], SSICG-7, have been synthesized using a mixed ligand approach. Strategic utilization of H2NIPA enables tunability in framework formation and generates coordinated water containing coordination polymers. The –NO2 group in H2NIPA is unlikely to bind directly with metal ions but draws solvent molecules near the metal center via H-bonding. The coordinated water molecules in SSICG-6 and 7 are reversible in nature, resulting in unsaturated metal centers that serve as excellent heterogeneous catalysts in CO2 cycloaddition and tone-pot Hantzsch condensation reactions. The near quantitative conversion of epichlorohydrin into its corresponding carbonate compound was successfully accomplished, employing SSICG-6 as a catalyst under solvent-free conditions. The unique coordination characteristics of SSICG-6 enhance its catalytic efficiency for larger substrates in CO2 cycloaddition reactions compared to other one-dimensional polymers. [ABSTRACT FROM AUTHOR]

The electrolysis of seawater has become a preferred method for hydrogen production since the current shortage of freshwater resources, offering an effective strategy to address the energy crisis. Nevertheless, this technology is limited by the following two factors: (i) low stability of catalytic materials at high-current density and (ii) accelerated corrosion rate of the electrode due to high concentrations of chloride ions (Cl−). Herein, an ultrafine phosphorus (P) and ruthenium (Ru) co-doped cerium dioxide (CeO2) self-supporting electrode (P, Ru–CeO2) was constructed via a high-pressure treatment strategy. Under the oxygen vacancies (Ov) in the CeO2 support and the anionic protective layer formed by the P–O bond, the electrode exhibits exceptional catalytic activity and durability in saline-alkali water, which only requires 291 mV to reach 1000 mA cm−2 in 1 M KOH + 1.5 M NaCl electrolyte. Besides, the electrode could operate stably at 1000 mA cm−2 over 100 h without significant attenuation, which can reach the level of industrial water electrolysis. This work presents a novel approach to designing and engineering excellent catalysts for industrial water electrolysis. [ABSTRACT FROM AUTHOR]

This document is a contents list for the journal "Dalton Transactions: An International Journal of Inorganic Chemistry." It provides a list of articles published in the journal, covering various topics in inorganic chemistry. The journal is published by The Royal Society of Chemistry, a reputable chemistry community. The document includes research papers on topics such as catalysis, spin state switching, targeted therapy for breast cancer, and photocatalysis. It also includes an expression of concern and a correction for previous papers. [Extracted from the article]

Dysregulation of Fibroblast Growth Factor Receptors (FGFRs) signaling has been associated with breast cancer, yet employing FGFR-targeted delivery systems to improve the efficacy of cytotoxic agents is still sparsely exploited. Herein, we report four new bi-functional ruthenium–peptide conjugates (RuPCs) with FGFR-targeting and pH-dependent releasing abilities, envisioning the selective delivery of cytotoxic Ru complexes to FGFR(+)-breast cancer cells, and controlled activation at the acidic tumoral microenvironment. The antiproliferative potential of the RuPCs and free Ru complexes was evaluated in four breast cancer cell lines with different FGFR expression levels (SKBR-3, MDA-MB-134-VI, MCF-7, and MDA-MB-231) and in human dermal fibroblasts (HDF), at pH 6.8 and pH 7.4 aimed at mimicking the tumor microenvironment and normal tissues/bloodstream pHs, respectively. The RuPCs showed higher cytotoxicity in cells with higher level of FGFR expression at acidic pH. Additionally, RuPCs showed up to 6-fold higher activity in the FGFR(+) breast cancer lines compared to the normal cell line. The release profile of Ru complexes from RuPCs corroborates the antiproliferative effects observed. Remarkably, the cytotoxicity and releasing ability of RuPCs were shown to be strongly dependent on the conjugation of the peptide position in the Ru complex. Complementary molecular dynamic simulations and computational calculations were performed to help interpret these findings at the molecular level. In summary, we identified a lead bi-functional RuPC that holds strong potential as a FGFR-targeted chemotherapeutic agent. [ABSTRACT FROM AUTHOR]

Achieving high photoelectrochemical conversion efficiency requires the logical layout of a composite photocatalyst with optimal charge separation and transfer with ideal light harvesting capabilities to enhance the photocatalytic performance and the degradation rate towards organic pollutants. Herein, a novel In2O3/WO3@Ti4N3Tx S-scheme heterojunction was successfully synthesized and confirmed through valence band VB-XPS and Mott Schottky combined analysis. The formed MXene-doped In2O3/WO3@Ti4N3Tx S-scheme significantly enhances the charge flow and spatial separation with an improved oxidation and reduction ability. An in-built interfacial electric field at the WO3–In2O3 boundary enhanced the light-harvesting capacity, whereas Ti4N3Tx MXene offers a unique electron trapping effect which effectively lowers high charge carrier recombination rate-related photocatalytic deficit. It preserves the exceptional redox potency of the photocatalyst by providing a directed acceleration and effective separation of the photogenerated charges. A high carrier density (ND = 7.83 × 1021 cm−3) with a lower negative flat band (VFB = −0.064 V vs. Ag/AgCl) was obtained by Mott–Schottky analysis for 3 wt% In2O3/WO3@Ti4N3Tx, an indicator that a low overpotential is needed to activate photocatalytic reactions. This study, therefore, provides a novel thought for the design and fabrication of an S-scheme heterojunction for photocatalytic reactions for mineralization of organic pollutants in water and clean energy production. [ABSTRACT FROM AUTHOR]

Thin films of Al as interconnect materials and those of AlN as wide bandgap semiconductor and piezoelectric material are of great interest for microelectronic applications. For the fabrication of these thin films via chemical vapor deposition (CVD) based routes, the available precursor library is rather limited, mostly comprising aluminium alkyls, chlorides, and few small amine-stabilized aluminium hydrides. Herein, we focused on rational precursor development for Al, their characterization and comparison to existing precursors comprising stabilized aluminium hydrides. We present and compare a series of potentially new and reported aluminium hydride precursors divided into three main groups with respect to their stabilization motive, and their systematic structural variation to evaluate the physicochemical properties. All compounds were comprehensively characterized by means of nuclear magnetic resonance spectroscopy (NMR), Fourier-transform infrared spectroscopy (FTIR), elemental analysis (EA), electron-impact ionization mass spectrometry (EI-MS) and thermogravimetric analysis (TGA). Promising representatives were further evaluated as potential single source precursors for aluminium metal formation in proof-of-concept experiments. Structure and reaction enthalpies with NH3 or H2 as co-reactants were calculated via first principles density functional theory simulations and show the great potential as atomic layer deposition (ALD) precursors for Al and AlN thin films. [ABSTRACT FROM AUTHOR]

The spinels ZnAl1.99−xHoxCr0.01O4 (with x = 0 and 0.001) were synthesized using a solid-state method, and various techniques were employed for their characterization. X-ray diffraction (XRD) analysis confirmed a cubic spinel structure with the Fd3¯m space group for both spinels. The morphology and homogeneity of the chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray analysis. Raman and infrared vibrational spectroscopy techniques were also employed for analysis. The optical band gap (Eg) was determined from UV/vis absorption spectra, and the direct transition behavior was confirmed by Tauc's law. The observed large disorder and defect concentration are attributed to the presence of Cr3+ and Ho3+ ions, explaining this behavior. The electron paramagnetic resonance (EPR) measurement presented different types of traps. Room temperature absorption spectra exhibited multiple peaks corresponding to the 3d–3d and 4f–4f transitions of Cr3+ and Ho3+ ions. The results obtained validate the significance of our compounds in optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Highly connected molecular building blocks (MBBs) have been demonstrated to play a crucial role in reticular chemistry, particularly in predicting the topologies of metal–organic frameworks. Metal phosphonate clusters exhibit considerable advantages in constructing high-connectivity MBBs, owing to the multiple coordination modes offered by phosphonic ligands. Herein, four metal (M = CoII, MnII) phosphonocarboxylate frameworks (CoPCF-1,2 and MnPCF-1,2) were successfully prepared under solvothermal conditions by utilizing the phosphonocarboxylic ligand, 4′-phosphonobiphenyl-3,5-dicarboxylic acid (H4pbpdc), and their structural characterization was performed using single-crystal X-ray diffraction (SCXRD). The structures feature a duodenary nuclear M12(µ3-OH)2(CO2)12(PO3)6(DMF)6/(CH3COO)4.5 cluster, bearing resemblance to the well-known Wells–Dawson ion from polyoxometallate chemistry. It is the first time a Wells–Dawson type cage has served as an 18-connected molecular building block, forming two kinds of porous metal phosphonocarboxylate frameworks with novel (3,18)-connected gez and gea topologies. Their permanent porosities were confirmed through N2 adsorption studies. Notably, the MBB Co12 cluster-based CoPCF-1 shows a loss and recovery process of µ3-OH through single-crystal-to-single-crystal (SCSC) transformation. The magnetic properties of the four compounds exhibit antiferromagnetic behavior. [ABSTRACT FROM AUTHOR]

In QDSSCs, a photoanode is an important part of connecting the external circuit, providing support for the transmission of photogenerated carriers to the external circuit, and also providing an attachment site for QDs. In this study, we prepared a g-C3N4@TiO2 composite for the photoanode by a two-step process. The results show that the use of g-C3N4@TiO2 greatly increases the specific surface area of the material, effectively inhibits the "electron–hole" recombination, and optimizes the stability and catalytic performance of the photoanode. Among them, the cell equipped with the g-C3N4@TiO2 photoanode has improved performance: Jsc = 26.5 mA cm−2, PCE = 8.2%, Voc = 0.62 eV, and FF = 0.50. Based on the research in this paper, it can be seen that the g-C3N4@TiO2 composite applied to the photoanode can effectively improve the cell performance and provide a feasible idea for optimizing QDSSCs. [ABSTRACT FROM AUTHOR]

Hexadentate poly-Lewis acids (PLA) based on the bowl-shaped tribenzotriquinacene (TBTQ) have been synthesised. The introduction of three n-propyl groups into the benzhydrylic positions of the TBTQ backbone has significantly increased the solubility of the subsequently derived compounds. Semi-flexible PLAs containing boron and aluminium were obtained by hydrometallation of the corresponding 2,3,6,7,10,11-hexaalkynyl-TBTQ. Other rigid hexadentate PLAs were synthesised by stannylation of the corresponding alkyne units with Me3SnNMe2 followed by tin-element exchange reactions. The Lewis acidity of these PLAs was investigated in host–guest experiments with pyridine. Further experiments with bidentate bases showed correlations between their flexibility, their Lewis basicity and the complexation behaviour towards the synthesised PLAs. Addition of bis((dimethylphosphino)methyl)dimethylsilane (BisPhos) to solutions of the rigid alkynyl PLAs led to the formation of 3 : 1 adducts. Single crystal X-ray diffraction was used to further elucidate the host–guest connectivtiy. In addition, a sixfold pnictogen-bonding donor was synthesised by tin-antimony exchange. [ABSTRACT FROM AUTHOR]

We have utilised the 4,6-di-tert-butyl resorcinol bis(diphenylphosphinite) (POCOP) ligand for exploring its coordination ability towards group 11 metal centres. The treatment of the bidentate ligand 1 with various coinage metal precursors afforded a wide range of structurally diverse complexes 2–12, depending upon the metal precursors used. This furnishes several multinuclear Cu(I) complexes with dimeric (2) and tetrameric cores (3, 4, and 5). The tetrameric stairstep complex 4 shows thermochromic behaviour, whereas the dimeric complex 2 and tetrameric complex 3 show luminescence properties at cryogenic temperatures. Interestingly, the halide substitution reaction of the dimeric complex 2 with KPPh2 produces a unique mixed phosphine-based tetrameric Cu(I) complex, 5. Treatment of the POCOP ligand with [CuBF4(CH3CN)4] in the presence of 2,2′-bipyridine afforded heteroleptic complex 6, consisting of tri- and tetra-coordinated cationic Cu(I) centres. Furthermore, we could also isolate cubane (8) and stairstep (9) complexes of Ag(I). The cationic Au(I) complex (12) was obtained from the dinuclear Au(I) complex of POCOP, 11. Complex 12 revealed the presence of a strong intramolecular aurophilic interaction with an Au⋯Au bond distance of 3.1143(9) Å. Subsequently, the photophysical properties of these complexes have been studied. All the complexes were characterised by single-crystal X-ray diffraction studies, routine NMR techniques, and mass spectroscopy. [ABSTRACT FROM AUTHOR]

The effects of polymethylene bridges on the chiroptical properties of trans-bis[(β-iminomethyl)naphthoxy]platinum(II) platforms were examined both experimentally and theoretically using newly designed planar chiral Pt analogues (1) having three-dimensional superstructures. A series of optically pure polymethylene-vaulted Pt complexes (R)- and (S)-1 were synthesized and characterized with regard to the chiroptical behaviour of the trans-bis[(β-iminomethyl)naphthoxy]platinum(II) platforms. These complexes were found to exhibit structure-dependent chiroptical characteristics in solution, such that the absolute values of specific rotation, the circular dichroism dissymmetry factor (gabs) and the circularly polarized luminescence dissymmetry factor (glum) all increased upon shortening the polymethylene bridges. Density functional theory and time dependent density functional theory calculations were used to analyse vaulted and non-vaulted complexes, which demonstrated that the present linker-dependent chiroptical properties resulted from constraint-induced changes in the square planar Pt coordination centres rather than from chiral distortion along the coordination platforms. [ABSTRACT FROM AUTHOR]

We describe the mononuclear anionic cyanido-pentafluorophenyl complexes, (NBu4)[Pt(C^N)(C6F5)(CN)] [C^N = 7,8-benzoquinolate (bzq) 1, 2-(2,4-difluorophenyl)pyridinate (dfppy) 2] and the heteropolynuclear derivatives [{Pt(C^N)(C6F5)(CN)}Tl] (C^N = bzq 3, dfppy 4). These complexes were synthesized via a two-step modular synthesis by reaction of the corresponding potassium salts K[Pt(C^N)(C6F5)(CN)], prepared in situ from [Pt(C^N)(C6F5)(DMSO)] and KCN in acetone/H2O, with TlPF6. The structures of {[Pt(bzq)(C6F5)(CN)Tl]·THF}n (3·THF)n and [{Pt(dfppy)(C6F5)(CN)}Tl]4·dioxane [4]4·dioxane, determined by X-ray crystallography, confirm the presence of Pt(II)–Tl(I) bonds [2.9795(6)–3.0736(3) Å], but in the dfppy complex, the incorporation of dioxane, causes a significant structural change. Thus, whereas [3·THF]n achieves a bent-ladder shape extended double chain Tl⋯[Pt⋯Tl]n⋯Pt supported by lateral bridging [Pt](μ-CN)[Tl] ligands, [4]4·dioxane is formed by discrete Pt4Tl4 rectangular aggregates stabilized by [Pt](μ-CN)[Tl] and Pt⋯Tl bonds, which are connected by dioxane bridging molecules through Tl⋯O(dioxane) additional contacts. Solid state emissions are redshifted compared with the mononuclear derivatives 1 and 2 and have been assigned, with the support of theoretical calculations on Pt4Tl4 models, to metal–metal′-to-ligand charge transfer (3MM′LCT [d/s σ*(Pt, Tl) → π*(C^N)]) for 3 and mixed 3MM′LCT/3IL for 4. In fluid THF solution, the complexes are not emissive. At 77 K, 3 and 4 exhibit bright emissions attributed to the formation of bimetallic [{Pt(C^N)(C6F5)(CN)}Tl(THF)x], and anionic [Pt(C^N)(C6F5)(CN)]− fragments. Furthermore, both 3 and 4 exhibit a reversible mechanochromism with a red shift of the emissions upon crushing, suggesting some degree of shortening of metal–metal separation. Finally, complex 3 shows solvatochromic behavior with color/luminescence changes by treatment with a drop of MeOH, CH2Cl2, THF or Et2O, with shifts from 583 in 3-MeOH to 639 nm in 3-THF. However, 4 only demonstrates a bathochromic response to MeOH. [ABSTRACT FROM AUTHOR]

Transition and rare earth metals serve as indispensable raw materials across a broad spectrum of technological applications. However, their utilization is frequently linked to substantial waste production. Consequently, the recycling and recovery of these metals from end-of-life products or metal-contaminated aqueous environments hold significant importance within the framework of a circular economy. In our investigation, we employed synthetic mesoporous silica monoliths, synthesized via the sol–gel method and functionalized with chelating groups, for the efficient recovery of metal ions from aqueous matrices. The monoliths were characterized using a multi-technique approach and were tested in the recovery of paramagnetic Gd3+, Cu2+ and Co2+ ions from aqueous solutions, using 1H-NMR relaxometry to evaluate their uptake performance in real time and under simple conditions. Detailed information on the kinetics of the capture process was also highlighted. Finally, the possibility to regenerate the solid sorbents was evaluated. [ABSTRACT FROM AUTHOR]

Among numerous biologically important metal cations, strontium (Sr2+) has received much attention in bone tissue regeneration because of its osteoinductive properties combined with its ability to inhibit osteoclast activity. In this study, strontium-doped hydroxyapatite (Sr-HAp) nanorods with varying molar ratios of Ca : Sr (10 : 0, 9 : 1, 5 : 5, 3 : 7 and 0 : 10) were synthesized using the chemical precipitation technique. The synthesized Sr-HAp nanostructures were characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman and Fourier transform infrared (FTIR) spectroscopies to understand their structural and morphological features, and composition. XRD results revealed the formation of HAp nanostructures, whose unit cell volume increased as a function of the dopant level. The reaction process investigation showed the formation of hydroxyapatite (HAp), strontium apatite (SAp) and various Sr-HAp phases. FESEM micrographs displayed the morphological transformation of Sr-HAp from nanorods to nanosheets upon increasing the dopant level. In the FTIR spectra, the bands of the PO43− group shifted towards a lower wavenumber upon increasing the dopant concentration in Sr-HAp that signifies the structural distortion due to the presence of a large amount of strontium ions. The peaks of PO43− and OH− vibrations in the Raman spectra were further analysed to corroborate the structural distortion of Sr-HAp. Selected area electron diffraction patterns obtained using TEM reveal the reduced crystallinity of Sr-HAp due to Sr-doping, which is in line with the XRD results. Finally, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that the synthesized Sr-HAp has no toxic effect on the survival and growth of mesenchymal stem cells. In summary, the synthesized novel Sr-HAp nanorods exhibit great promise for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

This study investigates the influence of ligand charge on transition energies in a series of CuN2S2 complexes based on dithiocarbazate Schiff base ligands using Cu K-edge X-ray absorption spectroscopy (XAS) and Kβ valence-to-core (VtC) X-ray emission spectroscopy (XES). By comparing the formally Cu(II) complexes [CuII(HL1)] (HL12− = dimethyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and [CuII(HL2)] (HL22− = dibenzyl pentane-2,4-diylidenebis[carbonodithiohydrazonate]) and the formally Cu(III) complex [CuIII(L2)], distinct changes in transition energies are observed, primarily attributed to the metal oxidation state. Density functional theory (DFT) calculations demonstrate how an increased negative charge on the deprotonated L23− ligand stabilizes the Cu(III) center through enhanced charge donation, modulating the core transition energies. Overall, significant shifts to higher energies are noted upon metal oxidation, emphasizing the importance of scrutinizing ligand structure in XAS/VtC XES analysis. The data further support the redox-innocent role of the Schiff base ligands and underscore the criticality of ligand protonation levels in future spectroscopic studies, particularly for catalytic intermediates. The combined XAS-VtC XES methodology validates the Cu(III) oxidation state assignment while offering insights into ligand protonation effects on core-level spectroscopic transitions. [ABSTRACT FROM AUTHOR]

Nanomaterials have attracted great interest in the field of photocatalytic degradation due to their larger specific surface area and efficient charge/mass transfer ability, which are beneficial for enhancing photocatalytic activity. However, the bandgap of photocatalysts would increase with the size reduction, weakening the photoabsorption ability. Thus the relationship between the size of catalysts and photoactivity should be balanced to achieve optimal photocatalytic performance. Herein, ultra-small CuWO4 nanoparticles (ca. 39 nm) with moderate oxygen vacancies (CuWO4–OVs) were synthesized by the cascade strategy (ligand confinement@fast calcination). The introduction of oxygen vacancies offset the deficiency of light absorption ability caused by the small size effect. Besides, oxygen vacancies could provide more reaction active sites, conducive to the adsorption and activation of dye molecules and H2O. Degradation experiments reveal that the optimized photocatalyst CuWO4–OVs 350 shows outstanding photocatalytic activity, and the removal ratio of methylene blue (MB) reaches over 90.26% in 70 min, exceeding that of pure CuWO4–air (37.66%). Additionally, the degradation performance of CuWO4–OVs 350 surpasses most of the other CuWO4-based photocatalytic systems. More importantly, the photocatalytic degradation activity of CuWO4–OVs 350 could remain at 88.26% even after five cycles, and high photostability was achieved. This work affords constructive inspiration for synergistic photoactivity enhancement and increase of catalyst reaction active sites to achieve eminent photocatalytic degradation performance. [ABSTRACT FROM AUTHOR]

The paper reports on the synthesis, crystal structure, thermal and magnetic properties of spin crossover (SCO) salts containing the [Fe(bpp)2]2+ cation (bpp = 2,6-bis(pyrazol-3-yl)pyridine) and different rigid polycarboxylate anions, such as anthracene-9,10-dicarboxylate (ADC), benzene-1,3,5-tricarboxylate (BTC) and biphenyl-4,4′-dicarboxylate (BPDC). Compound [Fe(bpp)2](ADC)·9H2O (1) shows a porous hydrogen-bonded structure with water molecules sitting in the channels. It contains low-spin (LS) Fe2+ cations that undergo crossover to the high-spin (HS) state upon dehydration. Anhydrous 1 remains HS on cooling at low temperatures. A similar magnetic behaviour is obtained for the partially protonated BTC salt [Fe(bpp)2](HBTC)·5H2O (2), showing a spin change concomitant with dehydration to a HS phase that undergoes gradual and partial SCO on cooling, affecting 25% of the Fe2+ cations. Instead, the BPDC salt [Fe(bpp)2](BPDC)·5H2O (3) has a ground HS state in its fully hydrated form. [ABSTRACT FROM AUTHOR]

The development of a new generation of anticorrosion pigments for paints remains an important challenge to replace the usual sparingly-soluble pigments and thus avoid the dissemination of heavy metals in the environment and the formation of holes in polymer coatings. For this purpose, α-zirconium hydrogenophosphate (Zr(HPO4)2·H2O, denoted as α-ZrP) was intercalated with the corrosion inhibitor 2-aminobenzimidazole (ABIM). Various microstructural analyses have proven the insertion of ABIM in the interlayer space by an acid–base exchange reaction and allowed us to propose a structural model for the new ABIM-ZrP pigment. The anticorrosion properties on zinc of the ABIM-ZrP, characterized by electrochemical measurements in 0.1 M NaCl, are due to the release of ABIM molecules by an ion-exchange reaction and the pH-buffer effect of α-ZrP and the amine group of ABIM. Compared to the commercial aluminium tri-phosphate (ATP) pigment, an alkyd-polymer coating loaded with the ABIM-ZrP pigment shows very interesting electrochemical behaviour by avoiding the blistering of the polymer coating and the beginning of zinc corrosion. This effect may be due to both the tortuous effect brought by the platelet shape of the pigments and the release of ABIM once the water uptake of the polymer becomes significant. [ABSTRACT FROM AUTHOR]

Rhenium(I) tricarbonyl complexes are widely studied for their cell imaging properties and anti-cancer and anti-microbial activities, but the complexes with S-donor ligands remain relatively unexplored. A series of six fac-[Re(NN)(CO)3(SR)] complexes, where (NN) is 2,2′-bipyridyl (bipy) or 1,10-phenanthroline (phen), and RSH is a series of thiocarboxylic acid methyl esters, have been synthesized and characterized. Cellular uptake and anti-proliferative activities of these complexes in human breast cancer cell lines (MDA-MB-231 and MCF-7) were generally lower than those of the previously described fac-[Re(NN)(CO)3(OH2)]+ complexes; however, one of the complexes, fac-[Re(CO)3(phen)(SC(Ph)CH2C(O)OMe)] (3b), was active (IC50 ∼ 10 μM at 72 h treatment) in thiol-depleted MDA-MB-231 cells. Moreover, unlike fac-[Re(CO)3(phen)(OH2)]+, this complex did not lose activity in the presence of extracellular glutathione. Taken together these properties show promise for further development of 3b and its analogues as potential anti-cancer drugs for co-treatment with thiol-depleting agents. Conversely, the stable and non-toxic complex, fac-[Re(bipy)(CO)3(SC(Me)C(O)OMe)] (1a), predominantly localized in the lysosomes of MDA-MB-231 cells, as shown by live cell confocal microscopy (λex = 405 nm, λem = 470–570 nm). It is strongly localized in a subset of lysosomes (25 μM Re, 4 h treatment), as shown by co-localization with a Lysotracker dye. Longer treatment times with 1a (25 μM Re for 48 h) resulted in partial migration of the probe into the mitochondria, as shown by co-localization with a Mitotracker dye. These properties make complex 1a an attractive target for further development as an organelle probe for multimodal imaging, including phosphorescence, carbonyl tag for vibrational spectroscopy, and Re tag for X-ray fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid materials have a range of applications due to their unique properties. Their application in agriculture brings alternatives for the controlled release of nutrients in the soil, the seed coating, the transport of herbicides, and the treatment of plant diseases. The present study aimed to investigate the use of fungicides incorporated into hybrid membranes formed by synthetic hectorite (LAPONITE®) and polymers in the pre-treatment of garlic bulbils exposed to the pathogen Stromatinia cepivora, which causes white rot. The coatings were selected by a germination test, based on the bulbil sprouting index, and by a mycelial growth inhibition test, based on the percentage of mycelial growth inhibition. The chosen membranes were used to coat the bulbils for bioassays conducted in a biochemical oxygen demand incubator at 17 °C. The coated bulbils were planted in soil samples containing three different densities of Stromatinia cepivora: 0.1 g, 1.0 g, and 10 g of sclerotium per L of soil. Membranes containing 2% carboxymethyl cellulose and 2% LAPONITE® incorporated with (i) the fungicide tebuconazole (36 mg L−1) and (ii) the combination of the actives tebuconazole (36 mg L−1) and triadimenol (62 mg L−1) showed the total rate of sprouting and null indices of incidence of symptoms and mortality in its repetitions. The hybrid membranes were characterized employing several techniques, including X-ray diffraction, infrared and Raman spectroscopy, thermogravimetric analysis and differential scanning calorimetry coupled to mass spectrometry, and optical microscopy. Characterization data confirmed the presence of fungicides incorporated into the membranes. Some concentrations of fungicides were low enough not to be detected in all analyses performed, although they guaranteed a protective character to the bulbils about the fungus S. cepivora present in the soil, with a possibility of antifungal pre-treatment with a potential reduction in the concentration used. [ABSTRACT FROM AUTHOR]

This density functional theory (DFT) study explores the efficacy of cooperative catalytic systems in enabling the ionic hydrogenation of N2 with H2, leading to NH3 formation. A set of N-heterocyclic carbene-based pincer tungsten/molybdenum metal complexes of the form [(PCP)M1(H)2] (M1 = W/Mo) were chosen to bind N2 at the respective metal centres. Simultaneously, cationic rhodium/iridium complexes of type [Cp*M2{2-(2-pyridyl)phenyl}(CH3CN)]+ (Cp* = C5(CH3)5 and M2 = Rh/Ir), are employed as cooperative coordination partners for heterolytic H2 splitting. The stepwise transfer of protons and hydrides to the bound N2 and intermediate NxHy units results in the formation of NH3. Interestingly, the calculated results reveal an encouraging low range of energy spans ranging from ∼30 to 42 kcal mol−1 depending on different combinations of ligands and metal complexes. The optimal combination of pincer ligand and metal center allowed for an energy span of unprecedented 29.7 kcal mol−1 demonstrating significant potential for molecular catalysts for the N2/H2 reaction system. While exploring obvious potential off-cycle reactions leading to catalyst deactivation, the computed results indicate that no increase in energy span would need to be expected. [ABSTRACT FROM AUTHOR]

In the process of handling and storage of radioactive actinides it is essential to selectively sequester the minor actinides, such as Am and Cm, through a competitive complexation process. Herein we computationally designed two core modified ligands (L21− and L3) through systematic oxygen substitution at the NH sites of dipyriamethyrin (L1_2H), a hexadentate expanded porphyrin, and studied their competitive complexation towards trivalent actinides (An = Am/Cm) from their trichlorides using density functional theory (DFT). We observed shorter An–N bonds and longer An–O bonds in complexes based on core modified ligands (L21− and L3). The An–Cl bond length increases with increasing axial coordination number (i.e., from L12− to L3) to accommodate the ligands. All the bonds were identified to be electrostatic in nature. L12− exhibits shorter bonds and larger bond orders on complexing with Am than with Cm. On moving from complexes of L21− to L3, the An–N bond lengths are shortened, while An–O bond lengths become larger. Between the complexes of Am and Cm, there is marginal difference in their bond distances with L21− and L3. Charge analysis shows ligand to metal charge transfer during coordination, with back-donation from An to N/O and Cl. The calculated spin-density analysis indicates that An remains in its trivalent oxidation state on complexation, while orbital occupation analysis shows that the 5f and 6d orbitals are involved in bonding; this was confirmed by molecular orbital (MO) analysis that shows the complexes of L21− and L3 to exhibit higher degeneracy in their overlapping MOs. Further, the energy decomposition analysis (EDA) confirms that all ionic bonds are primarily due to electrostatic contributions, where the orbital contributions increase from L12− to L3 complexes and maximum covalency was observed in Cm complexes due to the energy matching between the 5f orbitals of Cm and the 2p orbitals of N and Cl, compared to Am. To confirm the competitiveness in the complexation of the ligand towards Am vs. Cm, the thermodynamic parameters were analysed for the ligand and metal substitution reactions. L12− shows more affinity towards Am than Cm, while L21− and L3 prefer Cm. [ABSTRACT FROM AUTHOR]

In this study, we report the synthetic method of two distinct supramolecular metallogels, namely Mn-BDA and Cd-BDA, using Mn(II) acetate tetrahydrate, Cd(II) acetate dihydrate and butane-1,4-dicarboxylic acid (BDA). DMF, a polar aprotic solvent, was immobilized in both metallogel-networks for their synthesis. The metallogelation of Mn-BDA was successfully attained through the instant mixing of a Mn(II)-source and BDA in DMF solvent media. By applying ultrasonication, a Cd-BDA metallogel was prepared. The stoichiometry of gel-forming components concerning metal salts and the LMWG are accountable to obtain respective stable metallogels. Rheological parameters such as storage modulus (G′) and loss modulus (G′′) explored the mechanical flexibility of the synthesized metallogels through amplitude and angular frequency sweep experiments. Both the metallogels possess significant mechanical stability, which was determined by monitoring diverse gel-to-sol transition shear strain values (γ%). Distinctive morphological visualizations of both of these metallogels (i.e., Mn-BDA and Cd-BDA) were made via field emission scanning electron microscopic (FESEM) studies, demonstrating a fibrous inter-connected network with a hierarchical self-assembled arrangement for Mn(II)-based metallogels and a typical stacked-flake-like association with hierarchical motifs for Cd(II)-based metallogels. EDAX elemental mapping substantiated the presence of metallogel-forming agents such as individual metal acetate salts, BDA acting as a low-molecular weight gelator, and gel-immobilized solvents such as DMF. Furthermore, Fourier transform infrared spectroscopy and ESI-mass spectroscopy were performed for both these supramolecular metallogels. FT-IR spectroscopic and ESI-mass spectroscopic results clearly substantiate the possible non-covalent supramolecular interactions among basic molecular repeating moieties, i.e., butane-1,4-dicarboxylic acid (the low-molecular weight gelator), individual metal salts and gel-immobilized polar aprotic solvent DMF for the construction of distinct stable supramolecular metallogel-systems. The semiconducting property of the fabricated metallogels was investigated. Two Schottky diodes (SDs) composed of ITO/Cd-BDA/Al and ITO/Mn-BDA/Al in a sandwich pattern with Al serving as the metal electrode were fabricated. Both these metallogel-based devices effectively offer significant semiconducting diode features with non-linear J–V characteristics. The non-ohmic conduction protocol of the fabricated metallogel-based devices was explored. Mn-BDA and Cd-BDA metallogel-based fabricated devices have rectification ratios of 6.67 and 23.50, respectively. The gel-based diode performances were examined by observing the voltage-dependent current density, charge transportation and rectification ratio. [ABSTRACT FROM AUTHOR]

The four new ligands, dialkyl esters of (S,S)-propylenediamine-N,N′-di-(2,2′-di-(4-hydroxy-benzil))acetic acid (R2-S,S-pddtyr·2HCl) (R = ethyl (L1), propyl (L2), butyl (L3), and pentyl (L4)) and corresponding palladium(II) complexes have been synthesized and characterized by microanalysis, infrared, 1H NMR and 13C NMR spectroscopy. In vitro cytotoxicity was evaluated using the MTT assay on four tumor cell lines, including mouse mammary (4T1) and colon (CT26), and human mammary (MDA-MD-468) and colon (HCT116), as well as non-tumor mouse mesenchymal stem cells. Using fluorescence spectroscopy were investigated the interactions of new palladium(II) complexes [PdCl2(R2-S,S-pddtyr)]; (R = ethyl (C1), propyl (C2), butyl (C3), and pentyl (C4)) with calf thymus human serum albumin (HSA) and DNA (CT-DNA). The high values of the binding constants, Kb, and the Stern–Volmer quenching constant, KSV, show the good binding of all complexes for HSA and CT-DNA. The mentioned ligands and complexes were also tested on in vitro antimicrobial activity against 11 microorganisms. Testing was performed by the microdilution method, where the minimum inhibitory concentration (MMC) and the minimum microbicidal concentration (MMC) were determined. [ABSTRACT FROM AUTHOR]

A series of novel dinuclear NHC–gold–thiolato and –alkynyl complexes bearing aromatic linkers were successfully synthesized by an efficient and simple synthetic route. The catalytic activity of these complexes was tested in a lactonization reaction. The reaction proceeds in high efficiency, in short reaction time and under mild conditions, and is complementary to existing methods. Furthermore, the digold(I)–thiolato derivatives exhibit remarkable cytotoxicity towards several cancer cell lines. [ABSTRACT FROM AUTHOR]

The absence of better biomarkers currently limits early diagnosis and treatment of triple-negative breast cancer (TNBC). Our previously published study reported that the cyclic-peptide SD01 exhibited specific binding to EphA2 (Ephrin type-A receptor 2) on TNBC. To develop a novel PET imaging agent, we prepared gallium-68 (68Ga) labeled-DOTA-SD01 and evaluated its specificity and effectiveness through micro PET/CT imaging in a TNBC-bearing mouse model. SD01 and a control linear peptide YSA were conjugated to DOTA and subsequently labeled with 68Ga, obtaining 68Ga-DOTA-SD01 and 68Ga-DOTA-YSA. Both showed high radiochemical purity, stability, good hydrophilicity, and high binding affinity to 4T1 cells. Micro PET/CT imaging showed high radioactivity accumulation in tumors; SUVmean (mean standardized uptake value) of tumors in the group of 68Ga-DOTA-SD01 was 3.34 ± 0.25 and 2.65 ± 0.32 in the group of 68Ga-DOTA-YSA; T/NT ratios (target to non-target, SUVmean ratios of tumor to muscle) were 3.12 ± 0.06 and 2.77 ± 0.11 at 30 min, respectively (p < 0.05). The biodistribution study showed that tumor uptake % ID per g (percentage of injected dose per gram of tissue) in the group of 68Ga-DOTA-SD01 was 2.73 ± 0.34, and 1.77 ± 0.38 in the group of 68Ga-DOTA-YSA; T/NT ratios (radioactivity of tumor to muscle) were 3.55 ± 0.12 and 3.05 ± 0.10 for both groups at 30 min, respectively (p < 0.05). All these suggest that 68Ga-DOTA-SD01 may act as a better novel PET imaging agent for EphA2 positive tumors, such as TNBC. [ABSTRACT FROM AUTHOR]

Novel tricyclic 1,4-dihydro-1,4-phosphagermines (3a and 4a) were synthesised from Ge(NR2)2-bridged 1,3-imidazole-2-thione derivative 2a; all structures were crystallographically confirmed. In going from rather small alkyl substituents (Me, nBu) at the nitrogen centers of the 1,3-imidazole-2-thione units to sterically more demanding R = Mes and changing the employed Ge reagent from (R2N)2GeCl2 to R2NGeCl3 we achieved access to mixed functional bis(1,3-imidazole-2-thione)-substituted germanium derivative 2c. The latter was treated with MeLi and, subsequently, with PCl3 to yield a pentacyclic P,Ge-heterocycle (5); its formation was rationalized using DFT theoretical calculations. [ABSTRACT FROM AUTHOR]

Four bidentate boron Lewis acids based on the 1,8-diethynylanthracene backbone have been synthesized by a tin–boron exchange reaction with various chloroboranes, yielding the products in good to excellent yields. Complexation experiments of the host compounds with pyridine, pyrimidine and TMEDA demonstrated striking differences in terms of formation and solubility of the supramolecular adducts. The host–guest complexes were investigated by multinuclear NMR spectroscopy and structurally characterized by X-ray diffraction experiments, illustrating the adaptation of the host system upon adduct formation with different neutral guest molecules. [ABSTRACT FROM AUTHOR]

Organic crystal materials with metal-free feature and intrinsically low molecular mass are highly desirable for applications in flexible smart devices. Here, we reported a plastic crystal, tris(hydroxymethyl)aminomethane perchlorate (Tris-HClO4), which crystallizes in the R3¯ space group at room temperature and undergoes plastic phase transition at 369 K, showing a large entropy gain of 70.5 J mol−1 K−1, much higher than its fusion entropy gain (12.9 J mol−1 K−1). PXRD measurement indicates that it has cubic lattice symmetry in the high-temperature phase. Moreover, it exhibits excellent dielectric permittivity switching properties and robust cyclic stability. This work could be the pathway for chemical designing multifunctional switchable materials with the motive of combining the idea of symmetry breaking and plastic phase transition. [ABSTRACT FROM AUTHOR]

We have prepared a bis(compartmental) Mannich base ligand H4L (1,4,8,11-tetraaza-1,4,8,11-tetrakis(2-hydroxy-3-methoxy-5-methylbenzyl)cyclotetradecane) specifically designed to obtain bis(TMIILnIII) tetranuclear complexes (TM = transition metal). In this regard, we have succeeded in obtaining three new complexes of the formula [Zn2(μ-L)(μ-OAc)Dy2(NO3)2]·[Zn2(μ-L)(μ-OAc)Dy2(NO3)(OAc)]·4CHCl3·2MeOH (1) and [TM2(μ-H2L)2(μ-succinate)Ln2(NO3)2] (NO3)2·2H2O·6MeOH (TMII = Zn, LnIII = Dy (2); TMII = Co, LnIII = Dy (3)). Compound 1 contains two different bis(ZnDy) tetranuclear molecules that cocrystallize in the structure, in which acetato bridging ligands connect the ZnII and DyIII ions within each ZnDy subunit. This compound does not exhibit slow magnetic relaxation at zero field, but it is activated in the presence of an applied dc magnetic field and/or by Dy/Y magnetic dilution, showing two relaxation processes corresponding to each of the two different bis(ZnDy) units found in the structure. As revealed by the theoretical calculations, magnetic relaxation in 1 is single-ion in origin and takes place through the first excited state of each DyIII ion. When using the succinato dicarboxylate bridging ligand instead of acetate, compounds 2 and 3 were serendipitously formed, which have a closed structure with the succinate anion bridging two ZnDy subunits belonging to two different ligands. It should be noted that only compound 2 exhibits slow relaxation of magnetization in the absence of an external magnetic field. According to experimental and theoretical data, 2 relaxes through the second excited Kramers doublet (Ueff = 342 K). In contrast, 3 displays field-induced SMM behaviour (Ueff = 203 K). However, the Co/Zn diluted version of this compound 3Zn shows slow relaxation at zero field (Ueff = 347 K). Ab initio theoretical calculations clearly show that the weak ferromagnetic coupling between CoII and DyIII ions is at the origin of the lack of slow relaxation of this compound at zero field. Compound 2 and its diluted analogues 2Y and 3Zn show hysteresis loops at very low temperature, thus confirming their SMM behaviour. Finally, compounds 1 and 2 show DyIII based emission even at room temperature that, in the case of 2, allows us to extract the splitting of the ground 6H15/2 term, which matches reasonably well with theoretical calculations. [ABSTRACT FROM AUTHOR]

Novel temperature-sensitive luminescent materials, Ba2Gd2Ge4O13 doped with Bi3+, Bi3+/Sm3+ or Bi3+/Eu3+ ions, have been prepared using a conventional solid-state reaction technique. The XRPD study has verified that all the synthesized germanates crystallize in the monoclinic system (space group C2/c, Z = 4). The crystal lattice of the compounds consists of zigzag chains of edge-sharing Me2O7 (Me = Bi3+, Eu3+ or Sm3+) dimers, [Ge4O13] units, and ten-coordinated Ba atoms. Under UV excitation the powders exhibit the luminescence corresponding to the 3P1 → 1S0 (310–550 nm) transition in Bi3+ and 4G5/2 → 6HJ (550–730 nm) in Sm3+ or 5D0 → 7FJ (570–720 nm) transitions in Eu3+ ions. Heating of Ba2Gd1.94Bi0.01Sm0.05Ge4O13 and Ba2Gd1.89Bi0.01Eu0.1Ge4O13 phosphors leads to an irregular decrease in the intensity of the main emission lines. It has been found that the fluorescence intensity ratio between a wide band in the 310–530 nm region and peaks at longer wavelengths may be successfully used as a temperature-dependent characteristic. Absolute/relative sensitivity values for Ba2Gd1.94Bi0.01Sm0.05Ge4O13 and Ba2Gd1.89Bi0.01Eu0.1Ge4O13 germanates reach 0.19% K−1/0.80% K−1 and 2.21% K−1/0.58% K−1, respectively. The above parameters indicate that Ba2Gd2Ge4O13:Bi3+/Sm3+ or Bi3+/Eu3+ samples can be used as potential luminescent materials for non-contact temperature measurement. [ABSTRACT FROM AUTHOR]

In converting N2 to NH3 the enzyme nitrogenase utilises 8 electrons and 8 protons in the complete catalytic cycle. The source of the electrons is an Fe4S4 reductase protein (Fe-protein) which temporarily docks with the MoFe-protein that contains the catalytic active cofactor, FeMo-co, and an electron transfer cluster called the P cluster. The overall mechanism involves 8 repetitions of a cycle in which reduced Fe-protein docks with the MoFe-protein, one electron transfers to the P-cluster, and then to FeMo-co, followed by dissociation of the two proteins and re-reduction of the Fe-protein. Protons are supplied serially to FeMo-co by a Grotthuss proton translocation mechanism from the protein surface along a conserved chain of water molecules (a proton wire) that terminates near S atoms of the FeMo-co cluster [CFe7S9Mo(homocitrate)] where the multiple steps of the chemical conversions are effected. It is assumed that the chemical mechanisms use proton-coupled electron-transfer (PCET) and that H atoms (e− + H+) are involved in each of the hydrogenation steps. However there is neither evidence for, or mechanism proposed, for this coupling. Here I report calculations of cluster charge distribution upon electron addition, revealing that the added negative charge is on the S atoms of FeMo-co, which thereby become more basic, and able to trigger proton transfer from H3O+ waiting at the near end of the proton wire. This mechanism is supported by calculations of the dynamics of the proton transfer step, in which the barrier is reduced by ca. 3.5 kcal mol−1 and the product stabilised by ca. 7 kcal mol−1 upon electron addition. H tunneling is probable in this step. In nitrogenase it is electron transfer that triggers proton transfer. [ABSTRACT FROM AUTHOR]

Efficient catalysts for Guerbet-type ethanol/methanol upgrading to iso-butanol have been developed via Michael addition of a variety of amines to ruthenium-coordinated dppen (1,1-bis(diphenylphosphino)ethylene). All catalysts produce over 50% iso-butanol yield with >90% selectivity in 2 h with catalyst 1 showing the best activity (74% yield after this time). The selectivity and turnover number approach 100% and 1000 respectively using catalyst 6. The presence of uncoordinated functionalised donor groups in these complexes results in a more stable catalyst compared to unfunctionalised analogues. [ABSTRACT FROM AUTHOR]

Designing efficient, inexpensive, and stable photocatalysts to degrade organic pollutants and antibiotics has become an effective way for environmental remediation. In this work, we successfully performed in situ growth of CdS QDs on the surface of elliptical BiVO4 to try to show the advantage of the binary heterojuncted photocatalyst (BVO@CdS) for the photocatalytic degradation of tetracycline (TC). The In situ growth of CdS QDs can provide a large number of reactive sites and also generate a larger contact area with BiVO4. In addition, compared with mechanical composite materials, in situ growth can significantly reduce the energy barrier at the interface between BiVO4 and CdS, providing more channels for the separation and migration of photogenerated charge carriers, and further improving reaction activity. As a result, BVO@CdS-0.05 shows the best degradation efficiency, with a degradation rate of 88% after 30 min under visible light. The TC photodegradation follows a pseudo-second-order reaction with a dynamic constant of 0.472 min−1, which is 6.47 times that of pure BiVO4, 7.24 times that of pure CdS QDs and 2 times that of the mechanical composite. The degradation rate of BVO@CdS-0.05 decreases to 77.8% with a retention rate of 88.5% after four cycles, demonstrating excellent stability. Through liquid chromatography-mass spectrometry (LC-MS) analysis, two possible pathways for TC degradation are proposed. Through free radical capture experiments, electron spin resonance measurements, and photoelectrochemical comprehensive analysis, it is confirmed that BVO@CdS composites have constructed an efficient Z-scheme heterojunction via in situ growth, thereby highly enhancing the separation and transport efficiency of charge carriers. [ABSTRACT FROM AUTHOR]

Mn-doped Bi3O4Br has been synthesized using a solvothermal route. The undoped Bi3O4Br and Mn–Bi3O4Br materials possess orthorhombic unit cells with two distinct Bi sites forming a layered atomic arrangement. The shift in the (020) plane in the powder X-ray diffraction (PXRD) pattern confirms Mn-doping in the Bi3O4Br lattice. Elemental mapping indicated 7% Mn doping in the Bi3O4Br lattice structure. A core-level X-ray photoelectron study (XPS) indicates the presence of BiIII and MnII valence-states in Mn–Bi3O4Br. Doping with a cation (MnII) containing a different charge and ionic radius resulted in vacancy/defects in Mn–Bi3O4Br which further altered its electronic structure by reducing the indirect band gap, beneficial for electron conduction and electrocatalysis. The irreversible MnII to MnIII transformation at a potential of 1.48 V (vs. RHE) precedes the electrochemical oxygen evolution reaction (OER). The Mn-doped electrocatalyst achieved 10 mA cm−2 current density at 337 mV overpotential, while the pristine Bi3O4Br required 385 mV overpotential to reach the same activity. The pronounced OER activity of the Mn–Bi3O4Br sample over the pristine Bi3O4Br highlights the necessity of MnII doping. The superior activity of the Mn–Bi3O4Br catalyst over that of Bi3O4Br is due to a low Tafel slope, better double-layer capacitance (Cdl), and small charge-transfer resistance (Rct). The chronoamperometry (CA) study depicts long-term stability for 12 h at 20 mA cm−2. An electrolyzer fabricated as Pt(−)/(+)Mn–Bi3O4Br can deliver 10 mA cm−2 at a cell potential of 2.05 V. The post-CA-OER analyses of the anode confirmed the leaching of [Br−] followed by in situ formation of Mn-doped Bi2O3 as the electrocatalytically active species. Herein, an ultra-low Mn-doping into Bi3O4Br leads to an improvement in the electrocatalytic performance of the inactive Bi3O4Br material. [ABSTRACT FROM AUTHOR]

We propose a structurally simple, innovative, and multifunctional mid-infrared broadband thermally tunable metamaterial absorption device. The absorption device consists of a three-layer structure, from bottom to top: Ti substrate, SiO2 dielectric layer, and patterned VO2 layer. Through temperature control, the average absorption intensity of the absorption device can vary between 0.08 and 0.94. The absorption device's absorption mechanism is rooted in the thermal phase-change characteristics exhibited by the topologically patterned VO2. When the temperature is below 340 K, VO2 is in a dielectric state, resulting in near-total reflection performance in the mid-infrared range. When the temperature is above 340 K, VO2 undergoes a dielectric-to-metal transition, enabling the absorption device to achieve an average absorption rate of 94.12% in the ultra-wideband range of 6.26 μm–20.96 μm in the mid-infrared. This absorption range completely covers the atmospheric window wavelengths of 8 μm–14 μm, demonstrating high practical value. We explain the working mechanism of the absorption device from the perspective of the electromagnetic field. Subsequently, we study the variations in the absorption curve of the absorption device at different temperatures of VO2 and use the changes in the electric field at the same wavelength under different temperatures to explain the variations in absorption. Compared to previous work, our structure has only three layers in a single unit, making it easy to process and produce. Additionally, the absorption device's operating bandwidth and average absorption rate in the mid-infrared range have been significantly improved. Furthermore, the absorption device exhibits substantial incident angle tolerance and polarization insensitivity. We believe that this design has broad application potential in future optothermal conversion, infrared stealth, and thermal radiation. [ABSTRACT FROM AUTHOR]