Molecules

Research

9 pages, 3016 KiB

Open AccessArticle

Synthesis, Structure and Dye Adsorption Properties of Wine-Rack-Type Supramolecular Macrocycles Based on Polyoxovanadate

by Nasen Bate, Baoshan Hou and Hongmei Gan

Molecules 2025, 30(9), 2075; https://doi.org/10.3390/molecules30092075 - 7 May 2025

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Abstract

The precise construction and programmable assembly of structures with specific topologies remain persistent challenges in crystal engineering, primarily constrained by the limited availability of building blocks. Utilizing a synergistic approach that combines an in situ-formed concave polyoxovanadate (POV) cluster {VV₄} with [...] Read more.

The precise construction and programmable assembly of structures with specific topologies remain persistent challenges in crystal engineering, primarily constrained by the limited availability of building blocks. Utilizing a synergistic approach that combines an in situ-formed concave polyoxovanadate (POV) cluster {VV₄} with specifically designed 120° ditopic carboxylic acid bridging ligands, we successfully synthesized a series of wine-rack-type supramolecular macrocycles characterized by the general formula [(V₅O₉Cl)₄(L)₈]⁸⁻. The experimental results demonstrate that the introduction of sulfonic acid groups enables controlled structural extension into 1D chain and 2D layer architectures, manifesting the unique advantages of POV-based wine-rack units in constructing framework-based porous materials. This work significantly contributes to the structural diversity of wine-rack-type supramolecular architectures while simultaneously highlighting the great potential of polyoxometalate-driven supramolecular assemblies in materials science. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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10 pages, 3132 KiB

Open AccessCommunication

Interfacial Synthesis of an Electro-Functional 2D Bis(terpyridine)copper(II) Polymer Nanosheet

by Kenji Takada, Joe Komeda, Hiroaki Maeda, Naoya Fukui, Hiroyasu Masunaga, Sono Sasaki and Hiroshi Nishihara

Molecules 2025, 30(9), 2044; https://doi.org/10.3390/molecules30092044 - 4 May 2025

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Abstract

Coordination polymers are attractive materials for various fields of practical application. The high degree of freedom of choice of metal ions and organic ligands plays a critical role in functional diversification. In the present study, we report the liquid–liquid interfacial synthesis of a [...] Read more.

Coordination polymers are attractive materials for various fields of practical application. The high degree of freedom of choice of metal ions and organic ligands plays a critical role in functional diversification. In the present study, we report the liquid–liquid interfacial synthesis of a 2D bis(terpyridine)copper(II) polymer thin film, Cu-tpy. The synthesized Cu-tpy was characterized by various microscopic observations such as TEM, SEM, and AFM, and spectroscopic measurements such as XPS, Raman spectroscopy, SEM/EDS, and UV–Vis spectroscopy. Synchrotron-radiated X-ray scattering confirmed that Cu-tpy was oriented crystalline films. Moreover, Cu-tpy showed electrochemical micro-supercapacitor behavior in the solid-state owing to its ionic nature. This study expands the potential of bis(terpyridine)metal(II) polymers as electro-functional materials. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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12 pages, 4096 KiB

Open AccessArticle

Chiral Pseudo-D_6h Dy(III) Single-Molecule Magnet Based on a Hexaaza Macrocycle

by Jia-Hui Liu, Yi-Shu Jin, Jinkui Tang, Cai-Ming Liu, Yi-Quan Zhang and Hui-Zhong Kou

Molecules 2025, 30(9), 2043; https://doi.org/10.3390/molecules30092043 - 3 May 2025

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Abstract

A mononuclear complex [Dy(phenN₆)(HL′)₂]PF₆·CH₂Cl₂ (H₂L′ = R/S-1,1′-binaphthyl-2,2′-diphenol) with local D_6h symmetry was synthesized. Structural determination shows that Dy³⁺ was encapsulated within the coordination cavity of the neutral [...] Read more.

A mononuclear complex [Dy(phenN₆)(HL′)₂]PF₆·CH₂Cl₂ (H₂L′ = R/S-1,1′-binaphthyl-2,2′-diphenol) with local D_6h symmetry was synthesized. Structural determination shows that Dy³⁺ was encapsulated within the coordination cavity of the neutral hexaaza macrocyclic ligand phenN₆, forming a non-planar coordination environment. The axial positions are occupied by two phenoxy groups of binaphthol in the trans form. The local geometry of Dy³⁺ closely resembles a regular hexagonal bipyramid D_6h configuration. The axial Dy-O_phenoxy distances are 2.189(5) and 2.145(5) Å, respectively, while the Dy-N bond lengths in the equatorial plane are in the range of 2.524(7)–2.717(5) Å. The axial O_phthalmoxy-Dy-O_phthalmoxy bond angle is 162.91(17)°, which deviates from the ideal linearity. Under the excitation at 320 nm, the complex exhibits a characteristic emission peak at 360 nm, corresponding to the naphthalene ring. The AC susceptibility measurements under an applied DC field of 1800 Oe show distinct temperature-dependent and frequency-dependent AC magnetic susceptibility, typical of single-molecule magnetic behavior. The Cole–Cole plot in the temperature range of 6.0–28.0 K was fitted using a model incorporating Orbach and Raman relaxation mechanisms, giving an effective energy barrier of U_eff = 300.2 K. Theoretical calculations on complex 1 reveal that the magnetization relaxation proceeds through the first excited Kramers doublets with a calculated magnetization blocking barrier of 404.1 cm⁻¹ (581.4 K). Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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13 pages, 7718 KiB

Open AccessArticle

Recoverable and Sensitive Pressure-Induced Mechanochromic Photoluminescence of a Au-P Complex

by Ningwen Yang, Yijia Chang, Jiangyue Wang, David James Young, Hong-Xi Li, Yuxin Lu and Zhi-Gang Ren

Molecules 2025, 30(9), 2011; https://doi.org/10.3390/molecules30092011 - 30 Apr 2025

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Abstract

A binuclear Au-P complex [Au₂(2-bdppmapy)₂](PF₆)₂ (1) was synthesised by the reaction of 2-bdppmapy (N,N′-bis-(diphenylphosphanylmethyl-2-aminopyridine) with AuCN and [Cu(MeCN)₄]PF₆. The solid phase of 1 emitted bright yellow phosphorescence at λ_max [...] Read more.

A binuclear Au-P complex [Au₂(2-bdppmapy)₂](PF₆)₂ (1) was synthesised by the reaction of 2-bdppmapy (N,N′-bis-(diphenylphosphanylmethyl-2-aminopyridine) with AuCN and [Cu(MeCN)₄]PF₆. The solid phase of 1 emitted bright yellow phosphorescence at λ_max = 580 nm under UV excitation (QY = 4.41%, τ = 1.88 μs), which shifted to green (λ_max = 551 nm, QY = 5.73%) after being pressurised under 5 MPa. This colour change was recoverable upon exposure to CH₂Cl₂ vapor. Similar mechanochromic photoluminescence behaviour was observed after grinding the crystals of 1. A filter paper impregnated with 1 demonstrated recyclable write/erase functionality for encrypted information transfer. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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14 pages, 4714 KiB

Open AccessArticle

Investigating the Physical Adsorption of DCPD/Furfural and H₂ Adsorption–Dissociation Behaviors in RE-MOFs

by Muye Niu, Zuoshuai Xi, Chenhui He, Wenting Ding, Shanshan Cheng, Juntao Zhang and Hongyi Gao

Molecules 2025, 30(9), 1954; https://doi.org/10.3390/molecules30091954 - 28 Apr 2025

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Abstract

Metal–organic frameworks (MOFs) have emerged as promising catalysts in the hydrogenation of bicyclopentadiene (DCPD) and furfural. The physical adsorption behaviors of substrate molecules and H₂ within the pore structures of MOFs significantly influence the efficacy of subsequent catalytic reactions. This study employs [...] Read more.

Metal–organic frameworks (MOFs) have emerged as promising catalysts in the hydrogenation of bicyclopentadiene (DCPD) and furfural. The physical adsorption behaviors of substrate molecules and H₂ within the pore structures of MOFs significantly influence the efficacy of subsequent catalytic reactions. This study employs molecular dynamics (MD) simulations to identify the optimal temperature and pressure conditions for the adsorption of DCPD and H₂, as well as furfural and H₂, within rare-earth-element-based MOFs (RE-MOFs). By analyzing the physical adsorption characteristics of 1538 RE-MOFs, we investigate the correlation between pore structures and adsorption capabilities. This exploration has led to the identification of 10 RE-MOF structures that demonstrate superior physical adsorption performance for both DCPD and furfural. Following this initial evaluation, density functional theory (DFT) calculations were conducted to determine the chemisorption energies of H₂ molecules on these 10 selected RE-MOF structures. Notably, the structure identified as “JALLEQ_clean” exhibited the most optimal overall adsorption performance. This study elucidates the quantitative relationship between the pore structure of RE-MOFs and their physical adsorption performance, clarifying the influence of porosity parameters on adsorption capacity and highlighting the advantages of cluster-type structures in mass transfer and adsorption. The findings provide theoretical guidance for developing high-performance RE-MOF catalysts and offer new insights for the rational design of MOF-based catalytic materials. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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17 pages, 7697 KiB

Open AccessArticle

Power Frequency Breakdown Properties of LDPE-Doped Inorganic Nanoparticles

by Yujia Cheng and Guang Yu

Molecules 2025, 30(9), 1914; https://doi.org/10.3390/molecules30091914 - 25 Apr 2025

Viewed by 198

Abstract

Although polyethylene is widely used in electrical insulation, it does not possess dielectric properties. It is therefore desirable to develop insulation materials with excellent dielectric properties. In this study, low-density polyethylene (LDPE) was used as a matrix resin, while MgO, wollastonite, and montmorillonite [...] Read more.

Although polyethylene is widely used in electrical insulation, it does not possess dielectric properties. It is therefore desirable to develop insulation materials with excellent dielectric properties. In this study, low-density polyethylene (LDPE) was used as a matrix resin, while MgO, wollastonite, and montmorillonite (MMT) were employed as inorganic nano-additives. Three composites were prepared using the boiling–melt blending approach. Power frequency breakdown tests were performed on the original LDPE and on the prepared nanoparticle/LDPE composites. Upon combination with the Weibull distribution, the breakdown test results revealed that the addition of these nano-additive particles to the LDPE matrix increased the breakdown field strength of the material. The highest breakdown field strength for the nano-MgO/LDPE composite was obtained using a MgO loading of 0.5%. Notably, the obtained value was 1.8% higher than that of the pure LDPE. In addition, the highest breakdown field strength for the nano-wollastonite/LDPE composite was obtained using a wollastonite loading of 1% (7.48% higher than that of pure LDPE). Similarly, the highest breakdown field strength of the nano-MMT/LDPE composite was obtained using an MMT loading of 3%, giving a value that was 6.67% higher than that of the pure LDPE. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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19 pages, 7995 KiB

Open AccessArticle

Insights into the Factors Controlling the Origin of Activation Barriers in the [2 + 2] Cycloaddition Reactions of Heavy Imine-like Molecules Featuring a Ge=Group 15 Double Bond with Heterocumulenes

by Zheng-Feng Zhang and Ming-Der Su

Molecules 2025, 30(9), 1905; https://doi.org/10.3390/molecules30091905 - 25 Apr 2025

Viewed by 245

Abstract

The [2 + 2] cycloaddition reactions of the heterocumulene (N=C=N) with the heavy imine-like molecule Ge=G15-Rea (G15 = Group 15 element) were examined using density functional theory (M06-2X-D3/def2-TZVP). The theoretical findings indicate that the doubly bonded Ge=G15 moiety in Ge=G15-Rea (L [...] Read more.

The [2 + 2] cycloaddition reactions of the heterocumulene (N=C=N) with the heavy imine-like molecule Ge=G15-Rea (G15 = Group 15 element) were examined using density functional theory (M06-2X-D3/def2-TZVP). The theoretical findings indicate that the doubly bonded Ge=G15 moiety in Ge=G15-Rea (L₁L₂Ge=G15L₃) is characterized by electron-sharing bonding between the triplet L₁L₂Ge and triplet G15–L₃ fragments. All five Ge=G15-based heavy imine analogues readily undergo [2 + 2] cycloaddition reactions with N=C=N. Energy decomposition analysis (EDA–NOCV) suggests that the [2 + 2] cycloaddition reaction between Ge=G15-Rea and N=C=N involves a donor–acceptor (singlet–singlet) interaction instead of an electron-sharing (triplet–triplet) interaction. Frontier molecular orbital (FMO) theory and the energy decomposition analysis–natural orbitals for chemical valence (EDA–NOCV) findings emphasize that the key bonding interaction involves the occupied p-π orbital of Ge=G15-Rea and the vacant p-π* orbital of C=N=C. Based on the activation strain model results, the activation barrier of the [2 + 2] cycloaddition reaction is predominantly controlled by the deformation energies of Ge=G15-Rea and N=C=N. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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11 pages, 2692 KiB

Open AccessArticle

Hydrogenation-Facilitated Spontaneous N-O Cleavage Mechanism for Effectively Boosting Nitrate Reduction Reaction on Fe₂B₂ MBene

by Yuexuan He, Zhiwen Chen and Qing Jiang

Molecules 2025, 30(8), 1778; https://doi.org/10.3390/molecules30081778 - 15 Apr 2025

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Abstract

The electrochemical reduction of toxic nitrate wastewater to green fuel ammonia under mild conditions has become a goal that researchers have relentlessly pursued. Existing designed electrocatalysts can effectively promote the nitrate reduction reaction (NO₃RR), but the study of the catalytic mechanism [...] Read more.

The electrochemical reduction of toxic nitrate wastewater to green fuel ammonia under mild conditions has become a goal that researchers have relentlessly pursued. Existing designed electrocatalysts can effectively promote the nitrate reduction reaction (NO₃RR), but the study of the catalytic mechanism is not extensive enough, resulting in no breakthroughs in performance. In this study, a novel mechanism of hydrogenation-facilitated spontaneous N-O cleavage was explored based on density functional theory calculations. Furthermore, the E_ad−*OH (adsorption energy of the adsorbed *OH) was used as a key descriptor for predicting the occurrence of spontaneous N-O bond cleavage. We found that E_ad−*OH < −0.20 eV results into spontaneous N-O bond cleavage. However, excessively strong adsorption of OH* hinders the formation of water. To address this challenge, we designed the eligible Fe₂B₂ MBene, which shows excellent catalytic activity with an ultra-low limiting potential for NO₃RR of −0.22 V under this novel reaction mechanism. Additionally, electron-deficient Fe active sites could inhibit competing hydrogen evolution reactions (HERs), which provides high selectivity. This work may offer valuable insights for the rational design of advanced electrocatalysts with enhanced performance. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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16 pages, 2968 KiB

Open AccessArticle

A Site-Ordered Quadruple Perovskites, RMn₃Ni₂Mn₂O₁₂ with R = Bi, Ce, and Ho, with Different Degrees of B Site Ordering

by Alexei A. Belik

Molecules 2025, 30(8), 1749; https://doi.org/10.3390/molecules30081749 - 14 Apr 2025

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Abstract

A site-ordered quadruple perovskites, AA′₃B₄O₁₂, can have 3d transition metals at A′ and B sites, and show complex magnetic interactions and behavior. Additional complexity appears when B site-ordered arrangements are realized in AA′₃B₂ [...] Read more.

A site-ordered quadruple perovskites, AA′₃B₄O₁₂, can have 3d transition metals at A′ and B sites, and show complex magnetic interactions and behavior. Additional complexity appears when B site-ordered arrangements are realized in AA′₃B₂B′₂O₁₂. In this work, A site-ordered quadruple perovskites, RMn₃Ni₂Mn₂O₁₂ with R = Bi, Ce, and Ho, were prepared by a high-pressure, high-temperature method at about 6 GPa and about 1500 K. The R = Bi and Ce samples were found to crystallize in space group Im-3 with a disordered distribution of Ni²⁺ and Mn⁴⁺ cations in one B site. On the other hand, the R = Ho sample crystallized in space group Pn-3 and showed partial ordering of Ni²⁺ and Mn⁴⁺ cations between two B sites. The structural data (and bond valence sums) suggest that cerium has the oxidation state +3, which is unusual for such perovskites. Magnetic properties were investigated by magnetic susceptibility and specific heat measurements, which showed the presence of one magnetic transition near 36 K for R = Bi; there was evidence for the presence of two magnetic transitions near 27 K and 33 K for R = Ce, and near 10 K and 36 K for R = Ho. Curie–Weiss parameters were estimated for all samples from high-temperature magnetic measurements up to 750 K. The total effective magnetic moment for R = Ce also suggests the presence of Ce³⁺. A magnetic field of 90 kOe had the largest effect on the specific heat of the R = Ho sample, and almost no effects on the specific heat of the R = Bi sample. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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14 pages, 8111 KiB

Open AccessArticle

ALD-Deposited Hydroxyl-Rich NiO_x to Enhance SAM Anchoring for Stable and Efficient Perovskite Solar Cells

by Fengming Guo, Xuteng Yu, Yuheng Li, Yong Chen, Chi Li, Chunming Liu and Peng Gao

Molecules 2025, 30(6), 1299; https://doi.org/10.3390/molecules30061299 - 13 Mar 2025

Cited by 1 | Viewed by 684

Abstract

The interface between nickel oxide (NiO_x) and self-assembled monolayers (SAMs) in perovskite solar cells (PSCs) often suffers from limited adsorption strength, poor energy-level alignment, and inadequate defect passivation, which hinder device performance and stability. To address these issues, we introduce a [...] Read more.

The interface between nickel oxide (NiO_x) and self-assembled monolayers (SAMs) in perovskite solar cells (PSCs) often suffers from limited adsorption strength, poor energy-level alignment, and inadequate defect passivation, which hinder device performance and stability. To address these issues, we introduce a hybrid hole selective layer (HSL) combining atomic layer deposition (ALD)-fabricated NiO_x with full-aromatic SAM molecules, creating a highly stable and efficient interface. ALD NiO_x, enriched with hydroxyl groups, provides robust adsorption sites for the SAM molecule MeO-PhPACz, ensuring a strong, stable interaction. This hybrid HSL enhances energy-level alignment, hole selectivity, and defect passivation at the NiO_x/perovskite interface. Devices utilizing this approach demonstrate significant performance improvements, achieving a power conversion efficiency (PCE) of 21.74%, with reduced voltage losses and minimal hysteresis. Furthermore, operational stability tests reveal enhanced durability under elevated humidity and temperature conditions. These findings highlight the potential of ALD NiO_x and SAM hybrid HSL to overcome existing barriers, advancing the commercial viability of PSC technologies. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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17 pages, 7695 KiB

Open AccessArticle

High-Temperature X-Ray Crystal Structure Analysis of Schiff Base Cu(II) and Ni(II) Complexes and Data Statistics

by Anna Okui, Rin Tsuchiya, Daisuke Nakane, Takashiro Akitsu and Toby J. Blundell

Molecules 2025, 30(6), 1289; https://doi.org/10.3390/molecules30061289 - 13 Mar 2025

Viewed by 405

Abstract

In this study, single crystals of previously reported Schiff base copper (II) (Cu) and nickel (II) (Ni) complexes were synthesized; a structural analysis was performed using data measured at high temperatures, 298 K and 410 K; and CIF and [...] Read more.

In this study, single crystals of previously reported Schiff base copper (II) (Cu) and nickel (II) (Ni) complexes were synthesized; a structural analysis was performed using data measured at high temperatures, 298 K and 410 K; and CIF and electron density maps were obtained. The purpose of this study was to examine the accuracy of high-temperature measurements in X-ray crystal structure analyses and the details of atomic movement. Various data (statistics such as standard deviation) obtained from the structural analysis, such as the lattice constants, temperature factors, and electron density in cases without phase transitions, were compared. In addition, the anisotropic temperature factors were statistically processed. In the electron density map, the electron density tended to decrease at high temperatures. Looking at the two-dimensional fingerprint plot constructed from the Hirshfeld surface analysis, the intermolecular interactions between chlorine atoms and hydrogen atoms in the Cu changed significantly with the temperature change. In addition, the change in the anisotropic temperature factor of chlorine was significant. Moreover, a difference was observed in the analytical data at room temperature and high temperatures, which is thought to be useful for creating a model of temperature dependence. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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15 pages, 7751 KiB

Open AccessArticle

Study on the Extraction of Rare Earth Elements (REEs) from Phosphogypsum Using Gluconobacter oxydans Culture Solution

by Jiangang Zhang, Zhuo Qi, Zijian He, Xinyue Zhang, Qinglian Zhang and Xiangdong Su

Molecules 2025, 30(3), 674; https://doi.org/10.3390/molecules30030674 - 3 Feb 2025

Viewed by 718

Abstract

With the rapid development of modern industry, particularly in the fields of electric vehicles and renewable energy technologies, the demand for rare earth elements (REEs) has surged dramatically. Phosphogypsum (PG), which is an industrial waste product generated during the production of phosphoric acid [...] Read more.

With the rapid development of modern industry, particularly in the fields of electric vehicles and renewable energy technologies, the demand for rare earth elements (REEs) has surged dramatically. Phosphogypsum (PG), which is an industrial waste product generated during the production of phosphoric acid through the sulfuric acid process, is rich in REEs. However, traditional chemical leaching methods pose environmental pollution and resource wastage issues. This study aims to explore the feasibility and optimal conditions for bioleaching REEs from phosphogypsum using Gluconobacter oxydans (G. oxydans). The phase composition and components of phosphogypsum, as well as the growth characteristics and leaching efficiency of G. oxydans, were analyzed in detail using SEM, EDS, XRD, and XRF techniques. Experimental results indicate that G. oxydans can effectively leach REEs from phosphogypsum under conditions of 28 °C, an agitation speed of 150 rpm, and a liquid-to-solid ratio of 4:1, with a maximum leaching efficiency of 24.67%. Moreover, it is revealed in the study that G. oxydans exhibits selectivity in leaching REEs. Specifically, the leaching efficiency for Nd is significantly enhanced at low pH values. This research provides a theoretical basis and practical application example for the efficient and environmentally friendly recovery of REEs from phosphogypsum. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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15 pages, 4059 KiB

Open AccessArticle

Magnetically Diluted Dy³⁺ and Yb³⁺ Squarates Showing Relaxation Tuning and Matrix Dependence

by Rina Takano and Takayuki Ishida

Molecules 2025, 30(2), 356; https://doi.org/10.3390/molecules30020356 - 16 Jan 2025

Viewed by 636

Abstract

A new compound [Y₂(sq)₃(H₂O)₄] (Y-sq; sq = squarate (C₄O₄^2–)) was prepared and structurally characterized. Since the RE-sq family (RE = Y, Dy, Yb, Lu) gave isostructural crystals, the objective of [...] Read more.

A new compound [Y₂(sq)₃(H₂O)₄] (Y-sq; sq = squarate (C₄O₄^2–)) was prepared and structurally characterized. Since the RE-sq family (RE = Y, Dy, Yb, Lu) gave isostructural crystals, the objective of this study is to explore the effects of diamagnetic dilution on the SIM behavior through systematic investigation and comparison of diamagnetically diluted and undiluted forms. The 1%-Diluted Dy compounds, Dy@Y-sq and Dy@Lu-sq, showed AC magnetic susceptibility peaks without any DC bias field (H_DC), whereas undiluted Dy-sq showed no AC out-of-phase response under the same conditions. The Orbach and Raman mechanisms are assumed in the Arrhenius plots, giving U_eff/k_B = 139(5) and 135(8) K for Dy@Y-sq and Dy@Lu-sq, respectively, at H_DC = 0 Oe. In contrast, Yb@Y-sq and Yb@Lu-sq behaved different; Yb@Y-sq can be regarded as a field-induced SIM because AC out-of-phase response was recorded only when H_DC was present. On the other hand, Yb@Lu-sq showed a relaxation independent from temperature around 2 K at H_DC = 0 Oe, possibly ascribed to a quantum-tunneling-magnetization mechanism. Applying H_DC = 400 Oe afforded U_eff = 61.2(14) and 62.5(16) K for Yb@Y-sq and Yb@Lu-sq, respectively. The Y/Lu matrix dependence may be related to spin–phonon coupling. The dilution technique is a facile and versatile tool for modification of SIM characteristics. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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15 pages, 2952 KiB

Open AccessArticle

Eu-Substituents-Induced Modifications in the Thermoelectric Properties of the Zintl Phase Ba_1-xEu_xZn₂Sb₂ System

by Daewon Shim, Junsu Lee, Aziz Ahmed, Ji Hee Pi, Myung-Ho Choi, Kang Min Ok, Kyu Hyoung Lee and Tae-Soo You

Molecules 2025, 30(2), 310; https://doi.org/10.3390/molecules30020310 - 14 Jan 2025

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Abstract

Four quaternary Zintl phase thermoelectric (TE) materials belonging to the Ba_1-xEu_xZn₂Sb₂ (x = 0.02(1), 0.04(1), 0.08(1), 0.15(1)) system were successfully synthesized using the molten Pb-flux or the conventional high-temperature reaction methods. Their crystal structures [...] Read more.

Four quaternary Zintl phase thermoelectric (TE) materials belonging to the Ba_1-xEu_xZn₂Sb₂ (x = 0.02(1), 0.04(1), 0.08(1), 0.15(1)) system were successfully synthesized using the molten Pb-flux or the conventional high-temperature reaction methods. Their crystal structures were characterized by both powder and single-crystal X-ray diffraction analyses, and all four isotypic title compounds adopted the orthorhombic BaCu₂S₂-type (Pnma, Z = 4, Pearson code oP20) structure. The radius ratio criterion, based on the cationic and anionic elements (i.e., r₊/r₋), was successfully verified in the title system, as in our previous reports, where r₊/r₋ > 1 for the BaCu₂S₂-type structure. A series of density functional theory calculations were performed using a hypothetical model with the idealized compositions of Ba_0.75Eu_0.25Zn₂Sb₂, and the results were compared with the ternary parental compound BaZn₂Sb₂ to understand the influence of Eu substituents in the Ba_1-xEu_xZn₂Sb₂ system. A similar overall shape of the density of states (DOS) curves and the near-constant DOS values at E_F before and after the cationic substitution suggest only marginal changes in the carrier concentration. Therefore, carrier mobility has a dominant role in rationalizing the observed variations in the electrical transport properties of the title system. Temperature-dependent TE property measurements proved that an increase in the Seebeck coefficient S and a decrease in electrical conductivity σ were observed as the Eu substituents gradually increased in the Ba_1-xEu_xZn₂Sb₂ system, although the overall S and σ values were lower than those in the parental compound BaZn₂Sb₂. The thermal conductivities of these title compounds were successfully lowered by phonon scattering, but due to the overall smaller electrical transport properties, the observed maximum ZT was 0.49 at 773 K for Ba_0.98(1)Eu_0.02Zn₂Sb₂. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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12 pages, 6094 KiB

Open AccessArticle

A Fluorine-Functionalized Tb(III)–Organic Framework for Ba²⁺ Detection

by Yang Zhang, Hua Tan, Jiaping Zhu, Linhai Duan, Yuchi Ding, Fenglan Liang, Yongshi Li, Xinteng Peng, Ruomei Jiang, Jiaxin Yu, Jianjiong Fan, Yuhang Chen, Rimeng Chen and Deyun Ma

Molecules 2024, 29(24), 5903; https://doi.org/10.3390/molecules29245903 - 13 Dec 2024

Cited by 6 | Viewed by 947

Abstract

The development of lanthanide–organic frameworks (Ln-MOFs) using for luminescence sensing and selective gas adsorption applications is of great significance from an energy and environmental perspective. This study reports the solvothermal synthesis of a fluorine-functionalized 3D microporous Tb-MOF with a face-centered cubic (fcu [...] Read more.

The development of lanthanide–organic frameworks (Ln-MOFs) using for luminescence sensing and selective gas adsorption applications is of great significance from an energy and environmental perspective. This study reports the solvothermal synthesis of a fluorine-functionalized 3D microporous Tb-MOF with a face-centered cubic (fcu) topology constructed from hexanuclear clusters (Tb₆O₃₀) bridged by fdpdc ligands, formulated as {[Tb₆(fdpdc)₆(μ₃-OH)₈(H₂O)₆]·4DMF}_n (1), (fdpdc = 3-fluorobiphenyl-4,4′-dicarboxylate). Complex 1 displays a 3D framework with the channel of 7.2 × 7.2 Å² (measured between opposite atoms) perpendicular to the a-axis. With respect to Ba²⁺ cation, the framework of activated 1 (1a) exhibits high selectivity and reversibility in luminescence sensing function, with an LOD of 4.34665 mM. According to the results of simulations, compared to other small gas molecules (CO₂, N₂, H₂, CO, and CH₄), activated 1 (1a) shows a high adsorption selectivity for C₂H₂ at 298 K. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia)

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