Inorganics

20 pages, 4000 KiB

Open AccessArticle

Studies Toward Persilylation of π-Cyclopentadienyl Complexes of Fe and Ru. Molecular Structures of [Fe(C₅H₅){C₅(SiMe₂H)₅}], [Fe(C₅H₅){C₅Br₃(SiMe₃)₂}] and [Fe(C₅H₅){C₅Br₂(SiMe₃)₃}]

by Stefanie Bernhartzeder, Tobias Blockhaus, Markus Lang and Karlheinz Sünkel

Inorganics 2025, 13(2), 42; https://doi.org/10.3390/inorganics13020042 - 1 Feb 2025

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Abstract

Increasing the number of SiMe₃ substituents on a cyclopentadienyl ring has, in addition to a stabilizing effect of unusual coordination geometries and oxidation states, the effect of increasing the solubility in unpolar solvents and increasing the volatility. Starting from pentabromoferrocene and pentabromo(pentamethyl)ruthenocene, [...] Read more.

Increasing the number of SiMe₃ substituents on a cyclopentadienyl ring has, in addition to a stabilizing effect of unusual coordination geometries and oxidation states, the effect of increasing the solubility in unpolar solvents and increasing the volatility. Starting from pentabromoferrocene and pentabromo(pentamethyl)ruthenocene, we could achieve the introduction of up to five silyl (SiMe₂H or SiMe₃) groups to give [Fe(C₅H₅){C₅(SiMe₂R)₅}], R = H, Me, and [Ru(C₅Me₅){C₅(SiMe₂H)₅}]. However, yields were very low, and nearly all intermediate steps afforded mixtures of similar silyl-substituted compounds, which were difficult to separate. The crystal structures of [Fe(C₅H₅){C₅(SiMe₂H)₅}] (13a), [Fe(C₅H₅){C₅Br₃(SiMe₃)₂}] (4b), and [Fe(C₅H₅){C₅Br₂(SiMe₃)₃}] (8b) were determined. Full article

(This article belongs to the Special Issue State-of-the-Art Inorganic Chemistry in Germany)

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18 pages, 3247 KiB

Open AccessArticle

Pyridine vs. Thiazole in Cyclometalated N^C^N Ni(II) Complexes

by Lukas Kletsch, Rose Jordan, Julian Strippel, David A. Vicic and Axel Klein

Inorganics 2025, 13(2), 41; https://doi.org/10.3390/inorganics13020041 - 1 Feb 2025

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Abstract

Six N^C^N cyclometalated Ni(II) complexes [Ni(N^C^N)Cl] or [Ni(N^C^N’)Br] with symmetric N^C^N or non-symmetric N^C^N’ ligands in which the peripheral N-groups were varied with pyridine (Py), 4-thiazole (4Tz), 2-thiazole (2Tz), and 2-benzothiazole (2Btz) complementing the previously reported complexes with di(2-pyridyl)phenide ligands [Ni(Py(Ph)Py)X] X = [...] Read more.

Six N^C^N cyclometalated Ni(II) complexes [Ni(N^C^N)Cl] or [Ni(N^C^N’)Br] with symmetric N^C^N or non-symmetric N^C^N’ ligands in which the peripheral N-groups were varied with pyridine (Py), 4-thiazole (4Tz), 2-thiazole (2Tz), and 2-benzothiazole (2Btz) complementing the previously reported complexes with di(2-pyridyl)phenide ligands [Ni(Py(Ph)Py)X] X = Cl or Br. The non-symmetric [Ni(N^C^N’)Br] complexes were synthesized from NiBr₂ and N^CH^N’ protoligands through base-assisted nickelation, while the symmetric [Ni(N^C^N)Cl] complexes were received from the N^C(Cl)^N protoligands and [Ni(COD)₂] (COD = 1,5-cyclooctadiene). Introduction of 4Tz on both sides shifted the electrochemical gap ΔE_exp = E_ox–E_red and the long wavelength UV-vis absorption maxima of the complexes to higher energies, while 2Tz leads to a shift to lower energies. When introducing only one 4Tz or 2Tz as peripheral groups, the remaining PhPy moiety dominates the electronic properties and electrochemistry and photophysics are very similar to the Py(Ph)Py derivatives. In contrast to this, introduction of 2Btz shifts both values to lower energies, regardless of one or two 2Btz groups and the 2Btz moiety dominates the character of the frontier molecular orbitals of the complexes, as DFT calculations show. Long-wavelength UV-vis absorptions vary from 416 to 443 nm, and their energies correlate well with the first reduction potentials. Negishi-type C–C cross-coupling reactions gave total yields ranging from 1 to 60% and cross-coupling yields from 1 to 44%. The reactivities correlate roughly with the first reduction potentials. Facilitated reduction (E around –2 or higher) goes generally along with improved performance, making the thiazole-containing complexes interesting candidates for such catalysis. Full article

(This article belongs to the Special Issue Feature Papers in Organometallic Chemistry 2024)

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13 pages, 1765 KiB

Open AccessArticle

Unsymmetrical Bis(thiosemicarbazone) Ligands and Their Nickel(II) Complexes: Synthesis, Characterization and Photocatalytic Activity

by Rodrigo Burón, David G. Calatayud, M. A. Mendiola and Elena López-Torres

Inorganics 2025, 13(2), 40; https://doi.org/10.3390/inorganics13020040 - 29 Jan 2025

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Abstract

The widespread use of organic dyes in industrial processes has led to a considerable release of these compounds into water systems, making the removal of organic contaminants from freshwater a pressing challenge. Photocatalysis, particularly through coordination compounds, presents a promising solution to this [...] Read more.

The widespread use of organic dyes in industrial processes has led to a considerable release of these compounds into water systems, making the removal of organic contaminants from freshwater a pressing challenge. Photocatalysis, particularly through coordination compounds, presents a promising solution to this problem. In this study, we report the synthesis and characterization of three novel dissymmetric bis(thiosemicarbazone) ligands and their corresponding nickel(II) complexes, which have been extensively analyzed using various techniques. We evaluated the photocatalytic degradation of methyl orange by these nickel complexes, with results demonstrating that they exhibit superior efficiency compared to previously reported nickel-based complexes. Theoretical calculations reveal a correlation between the HOMO–LUMO energy gap and the energies of the involved orbitals. Additionally, with the growing demand for sustainable fuels that do not contribute to greenhouse gas emissions, molecular hydrogen stands out as a promising candidate. Given the potential of bis(thiosemicarbazone) complexes for electrocatalytic hydrogen evolution, we performed preliminary experiments to assess the ability of these nickel complexes to function as photocatalysts for water splitting. The results show that the three nickel complexes successfully generate hydrogen under the tested conditions, although further optimization is necessary to improve hydrogen production efficiency. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series in “Featuring Ligands and Their Applications in Coordination Chemistry”)

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11 pages, 6300 KiB

Open AccessArticle

Chiral Layered Zinc Phosphonates: Exfoliation and Chiroptical Properties

by Zi-Xin Yang, Sheng-Fu Wu, Song-Song Bao, Xiu-Fang Ma, Tao Zheng and Li-Min Zheng

Inorganics 2025, 13(2), 39; https://doi.org/10.3390/inorganics13020039 - 28 Jan 2025

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Abstract

Chiral layered coordination polymers have attracted considerable attention not only because of their intriguing physicochemical properties but also because of their ability to exfoliate into chiral nanosheets. Chiral metal phosphonates with layered structures are of particular interest due to their relatively high thermal [...] Read more.

Chiral layered coordination polymers have attracted considerable attention not only because of their intriguing physicochemical properties but also because of their ability to exfoliate into chiral nanosheets. Chiral metal phosphonates with layered structures are of particular interest due to their relatively high thermal and water stabilities, but their corresponding nanosheets are rarely reported on. Herein, we report on a pair of enantiopure zinc phosphonates with the formula S- and R-Zn₈(cyampH)₈Cl₈ (S-Zn, R-Zn), where S- and R-cyampH₂ represent S- and R-(1-cyclohexylamino)methylphosphonic acids. They have layered structures in which the {ZnO₃Cl} tetrahedra are connected by {PO₃C} tetrahedra via corner-sharing. By doping analogous chromophore ligands S- and R-(1-naphthalenethylamino)methylphosphonic acid (S-, R-nempH₂), we obtained compounds S- and R-Zn₈(cyampH)_8-n(nempH)_nCl₈ (S-, R-Zn-x%, x = 2, 4, 6), which exhibited obvious circular dichroism (CD) and circularly polarized luminescence (CPL) properties. The bulk samples of S-Zn and S-Zn-4% were further subjected to exfoliation in acetone, resulting in chiral nanosheets of one–three-layer thicknesses. Full article

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19 pages, 1753 KiB

Open AccessReview

Anticancer and Antimicrobial Activity of Copper(II) Complexes with Fluorine-Functionalized Schiff Bases: A Mini-Review

by María Esther Moreno-Narváez, Lucero González-Sebastián, Raúl Colorado-Peralta, Viviana Reyes-Márquez, Luz Ofelia Franco-Sandoval, Adriana Romo-Pérez, Jesús Antonio Cruz-Navarro, Ivone Vanessa Mañozca-Dosman, Alberto Aragón-Muriel and David Morales-Morales

Inorganics 2025, 13(2), 38; https://doi.org/10.3390/inorganics13020038 - 26 Jan 2025

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Abstract

In recent years, metallodrugs have emerged as captivating and promising compounds in the fields of cancer therapy and antimicrobial agents. While noble metals have shown remarkable biological activity, increasing interest lies in utilizing more abundant and cost-effective metals in medicinal chemistry. This is [...] Read more.

In recent years, metallodrugs have emerged as captivating and promising compounds in the fields of cancer therapy and antimicrobial agents. While noble metals have shown remarkable biological activity, increasing interest lies in utilizing more abundant and cost-effective metals in medicinal chemistry. This is primarily due to their pivotal role in biological processes and their lower cost compared to precious metals. Among these, copper(II) complexes have emerged with promising applications in medicine. Notably, copper compounds bearing Schiff bases stand out as innovative metallodrugs. They exhibit intriguing cytotoxic properties against a wide range of cancer cell lines, while also demonstrating inhibitory effects on prevalent bacterial and fungal strains. Nevertheless, research into Cu(II) complexes with Schiff bases remains of paramount interest. One strategic avenue to bolster their biological activity involves the introduction of fluorine groups into the ligands. This approach has demonstrated a significant augmentation in efficacy and selectivity, particularly in targeting cancer cells and microbial pathogens, because fluorine incorporation can improve metabolic stability and cellular uptake. This further reinforces the therapeutic potential of these metallodrugs. Thanks to these promising outcomes, research into the development of Cu(II) complexes with fluorinated Schiff bases is advancing significantly. This holds immense potential for progressing the field of medicinal chemistry, with the aim of addressing unmet clinical needs in both cancer therapy and antimicrobial treatment. This review comprehensively explores the latest advancements in Cu(II) complexes bearing fluorinated Schiff bases, encompassing diverse coordination modes. It delves into their scope and applications in cytotoxic evaluations, as well as their efficacy as antimicrobial and antifungal agents. Full article

(This article belongs to the Special Issue Current Advances in Coordination and Bioinorganic Chemistry)

19 pages, 960 KiB

Open AccessArticle

Hierarchically Porous Titanosilicate Hollow Spheres Containing TS-1 Zeolite Precursors for Oxidative Desulfurization

by Yao Wang, Hongda Yu, Huan Wang and Tiehong Chen

Inorganics 2025, 13(2), 37; https://doi.org/10.3390/inorganics13020037 - 25 Jan 2025

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Abstract

The environmental and health impacts of sulfur compounds in fuel oil have prompted considerable research interest in oxidative desulfurization (ODS) technology. Tetrahedrally coordinated titanium has been demonstrated to exhibit excellent activity in the context of oxidative desulfurization processes. However, further improving the catalytic [...] Read more.

The environmental and health impacts of sulfur compounds in fuel oil have prompted considerable research interest in oxidative desulfurization (ODS) technology. Tetrahedrally coordinated titanium has been demonstrated to exhibit excellent activity in the context of oxidative desulfurization processes. However, further improving the catalytic property of the tetrahedrally coordinated titanium remains a challenging endeavor. In the context of ODS processes conducted at near room temperatures, the improvement of conversion remains a subject of considerable challenge. In this study, hierarchically porous titanosilicate hollow spheres were synthesized by using TS-1 zeolite precursors as Ti and Si sources to obtain the catalyst with only tetrahedrally coordinated titanium. The synthesized materials were characterized through transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis), and nitrogen adsorption analysis. These techniques confirmed the formation of hollow spherical hierarchically porous structures with Ti species uniformly incorporated in tetrahedral coordination and the presence of five-member rings of TS-1 zeolite. As a result, the hierarchically porous titanosilicate hollow spheres demonstrated excellent catalytic performance in ODS, achieving complete dibenzothiophene (DBT) removal within 15 min and a high turnover frequency (TOF) of up to 123 h⁻¹ at 30 °C. Full article

(This article belongs to the Special Issue Feature Papers in Inorganic Materials 2024)

10 pages, 1945 KiB

Open AccessCommunication

Homo-Chromophores in Cu(I)(XXX), (X₃ = N₃, C₃, Cl₃, S₃, P₃, Br₃, or I₃) Derivatives—Structural Aspects

by Milan Melník, Veronika Mikušová and Peter Mikuš

Inorganics 2025, 13(2), 36; https://doi.org/10.3390/inorganics13020036 - 25 Jan 2025

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Abstract

The structural aspects of homo-chromophores in Cu(I)(XXX) complexes, where X₃ = N₃, C₃, Cl₃, S₃, P₃, Br₃, or I₃, are analyzed in this study. These copper(I) derivatives crystallize [...] Read more.

The structural aspects of homo-chromophores in Cu(I)(XXX) complexes, where X₃ = N₃, C₃, Cl₃, S₃, P₃, Br₃, or I₃, are analyzed in this study. These copper(I) derivatives crystallize in five distinct crystal systems as follows: rhombohedral (1 example), trigonal (1 example), orthorhombic (4 examples), triclinic (5 examples), and monoclinic (15 examples). The angular distortion from regular trigonal geometry increases in the following order: Cu(ClClCl) < Cu(NNN) < Cu(PPP) < Cu(BrBrBr) < Cu(III) < Cu(CCC) < Cu(SSS). For Cu(I)(XX) complexes, the deviation from linear geometry increases in the order: Cu(SeSe) < Cu(SS) < Cu(OO) < Cu(ClCl) < Cu(NN) < Cu(CC) < Cu(PP) < Cu(BrBr). The structural parameters of Cu(I)(XXX) are examined, discussed, and compared with those of homonuclear Cu(I)(XX) complexes. Full article

(This article belongs to the Special Issue Applications and Future Trends for Novel Copper Complexes)

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12 pages, 1066 KiB

Open AccessArticle

Preparation of a New Active Component 1,10-B₁₀H₈(S(C₁₈H₃₇)₂)₂ for Potentiometric Membranes for the Determination of Terbinafine Hydrochloride

by Eugeniy S. Turyshev, Alexey V. Golubev, Alexander Yu. Bykov, Konstantin Yu. Zhizhin and Nikolay T. Kuznetsov

Inorganics 2025, 13(2), 35; https://doi.org/10.3390/inorganics13020035 - 24 Jan 2025

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Abstract

This paper presents a methodology for the preparation of a new active component for ion-selective membranes, based on a di-substituted sulfonium derivative of the closo-decaborate anion at the apical vertices with the octadecylalkyl substituents 1,10-B₁₀H₈(S(C₁₈H₃₇ [...] Read more.

This paper presents a methodology for the preparation of a new active component for ion-selective membranes, based on a di-substituted sulfonium derivative of the closo-decaborate anion at the apical vertices with the octadecylalkyl substituents 1,10-B₁₀H₈(S(C₁₈H₃₇)₂)₂. This approach is characterized by physicochemical methods of analysis (11B, 1H, 13C NMR spectroscopy, IR spectroscopy and elemental analysis). The compound obtained is used as an active component of a PVC membrane selective to terbinafine hydrochloride. The sensor developed is highly selective to the drug to be detected, has a linearity range of 4.0 × 10⁻⁸–1.0 × 10⁻² and a detection limit of 1.0 × 10⁻⁸, and can detect terbinafine hydrochloride in the pH range of 3 to 6. Full article

(This article belongs to the Section Inorganic Materials)

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12 pages, 5569 KiB

Open AccessArticle

Structural and Magnetic Properties of Biogenic Nanomaterials Synthesized by Desulfovibrio sp. Strain A2

by Mikhail S. Platunov, Yuriy V. Knyazev, Olga P. Ikkert, Olga V. Karnachuk, Anton D. Nikolenko, Roman D. Svetogorov, Evgeny V. Khramov, Mikhail N. Volochaev and Andrey A. Dubrovskiy

Inorganics 2025, 13(2), 34; https://doi.org/10.3390/inorganics13020034 - 23 Jan 2025

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Abstract

This study explores the phase composition, local atomic structure, and magnetic properties of biogenic nanomaterials synthesized through microbially mediated biomineralization by the sulfate-reducing bacterium Desulfovibrio species strain A2 (Cupidesulfovibrio). Using X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, X-ray absorption [...] Read more.

This study explores the phase composition, local atomic structure, and magnetic properties of biogenic nanomaterials synthesized through microbially mediated biomineralization by the sulfate-reducing bacterium Desulfovibrio species strain A2 (Cupidesulfovibrio). Using X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, X-ray absorption near-edge structure (XANES) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy, and magnetic measurements, we identified a mixture of vivianite (Fe₃(PO₄)₂·8H₂O) and sulfur-containing crystalline phases (α-sulfur). XRD analysis confirmed that the vivianite phase, with a monoclinic I2/m structure, constitutes 44% of the sample, while sulfur-containing phases (α-sulfur, Fddd) account for 56%, likely as a result of bacterial sulfate-reducing activity. X-ray absorption spectroscopy (XAS) and EXAFS revealed the presence of multiple sulfur oxidation states, including elemental sulfur and sulfate (S⁶⁺), underscoring the role of sulfur in the sample’s structure. Mössbauer spectroscopy identified the presence of ferrihydrite nanoparticles with a blocking temperature of approximately 45 K. Magnetic measurements revealed significant coercivity (~2 kOe) at 4.2 K, attributed to the blocked ferrihydrite nanoparticles. The results provide new insights into the structural and magnetic properties of these microbially mediated biogenic nanomaterials, highlighting their potential applications in magnetic-based technologies. Full article

(This article belongs to the Topic Advances in Inorganic Synthesis)

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12 pages, 3976 KiB

Open AccessArticle

Magnetic and Thermoelectric Properties of Fe₂CoGa Heusler Compounds

by Tetsuji Saito and Hayai Watanabe

Inorganics 2025, 13(2), 33; https://doi.org/10.3390/inorganics13020033 - 23 Jan 2025

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Abstract

The investigation of the properties of Heusler compounds is an important task that will pave the way for new applications in various fields related to magnetics and thermoelectrics. This study examines the magnetic and thermoelectric properties of Fe₂CoGa Heusler compounds prepared [...] Read more.

The investigation of the properties of Heusler compounds is an important task that will pave the way for new applications in various fields related to magnetics and thermoelectrics. This study examines the magnetic and thermoelectric properties of Fe₂CoGa Heusler compounds prepared by casting and subsequent annealing. The Fe₂CoGa Heusler compound was found to be ferromagnetic, with a large saturation magnetization of 110 emu/g and a high Curie temperature of 1011 K. The Fe₂CoGa Heusler compound was a good thermoelectric material, with a negative Seebeck coefficient of −44 μV/K, a low electrical resistivity of 0.60 μΩm, and a high-power factor of 3000 μW/mK² at room temperature. The maximum power factor of 3230 μW/mK² for the Fe₂CoGa Heusler compound was obtained at 400 K. In order to improve the magnetic and thermoelectric properties of the Fe₂CoGa Heusler compound, Fe_2-xCo_1+xGa (x = 0–1) Heusler compounds were also prepared by casting and subsequent annealing. In the Fe_2-xCo_1+xGa (x = 0–1) Heusler compounds, the saturation magnetization slightly decreased, but the Curie temperature increased with increasing Co content (x). As regards the thermoelectric properties, the electrical resistivity of the Fe_2-xCo_1+xGa (x = 0.25–1) Heusler compounds was smaller than that of the Fe₂CoGa Heusler compound. The Seebeck coefficient and power factor of the Fe_1.75Co_1.25Ga Heusler compound were more significant than those of the Fe₂CoGa Heusler compound. An increase in the Co content of the Fe₂CoGa Heusler compound did not improve the saturation magnetization but improved the Curie temperature and thermoelectric properties of the Fe₂CoGa Heusler compound. The Fe_1.75Co_1.25Ga Heusler compound exhibited a high-power factor value of over 4000 μW/mK², which was comparable to that of the Bi₂Te₃ compound. Full article

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13 pages, 3644 KiB

Open AccessArticle

Insights into Contribution of Active Ceria Supports to Pt-Based Catalysts: Doping Effect (Zr; Pr; Tb) on Catalytic Properties for Glycerol Selective Oxidation

by Matías G. Rinaudo, Maria del Pilar Yeste, Hilario Vidal, José M. Gatica, Luis E. Cadús and Maria R. Morales

Inorganics 2025, 13(2), 32; https://doi.org/10.3390/inorganics13020032 - 22 Jan 2025

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Abstract

How important is the support during the rational design of a catalyst? Herein, doped ceria (Zr; Pr and Tb) was used as an active support to prepare Pt catalysts (0.5 wt%) for glycerol selective oxidation. A thorough characterization of achieved catalytic systems showed [...] Read more.

How important is the support during the rational design of a catalyst? Herein, doped ceria (Zr; Pr and Tb) was used as an active support to prepare Pt catalysts (0.5 wt%) for glycerol selective oxidation. A thorough characterization of achieved catalytic systems showed that the nature of doping elements led to different physicochemical properties. The presence of surface Pr³⁺ and Tb³⁺ not only increased oxygen vacancies but also electron mobility, modifying the oxidation state of platinum particles. The redox properties of the catalyst were also affected, achieving a close interaction between the support and metal particles even in the form of Pt-O-Pr(Tb) solid solutions. Furthermore, the combination of medium-sized metal particle dispersion, strong metal–support interaction and a synergy between the amount of oxygen vacancies and Pt⁰, observed in the Pt/CeTb catalyst, led to a high turnover frequency (TOF) and increased selectivity to glyceric acid. Thus, the present study reveals how a simple structural modification of active supports, such as cerium oxide, by means of doping elements is capable of improving the catalytic performance during glycerol selective oxidation, avoiding the cumbersome methods of synthesis and activation treatments. Full article

(This article belongs to the Special Issue Transition Metal Catalysts: Design, Synthesis and Applications)

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17 pages, 19149 KiB

Open AccessArticle

Heterostructure Based of Ti-TiO₂(NW)/rGO Hybrid Materials for Electrochemical Applications

by Mina-Ionela Morariu (Popescu), Mircea Nicolaescu, Corina Orha, Carmen Lăzău, Narcis Duteanu and Cornelia Bandas

Inorganics 2025, 13(2), 31; https://doi.org/10.3390/inorganics13020031 - 22 Jan 2025

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This study investigated a hybrid electrode based on titanium/titanium dioxide nanowires/reduced graphene oxide (Ti-TiO₂(NW)/rGO) that was developed in two stages. The Ti-TiO₂(NW)/rGO was obtained by hydrothermal treatment in a mixed solution of H₂O₂ and melamine for [...] Read more.

This study investigated a hybrid electrode based on titanium/titanium dioxide nanowires/reduced graphene oxide (Ti-TiO₂(NW)/rGO) that was developed in two stages. The Ti-TiO₂(NW)/rGO was obtained by hydrothermal treatment in a mixed solution of H₂O₂ and melamine for Ti-TiO₂ support, followed by a simple spin-coating deposition method and thermal oxidation in a controlled atmosphere of nitrogen gas (99%). The as-prepared structures of electrodes were characterized using ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). In addition, the electrochemical behavior was assessed by cyclic voltammetry (CV) in a 1M HNO₃-supporting electrolyte and in the presence of 4 mM K₄Fe(CN)₆ 3H₂O to determine the electroactive surface area and apparent diffusion coefficient of the hybrid electrode. The development of the Ti-TiO₂(NW)/rGO hybrid electrode provides a sensitive method for photo-electrooxidation of doxorubicin due to exploiting the synergistic and remarkable properties of the nanowires of TiO₂ and of reduced graphene oxide (rGO) layer on the electrode surface. Full article

(This article belongs to the Special Issue Nano-Design of Transition Metal Oxides for Energy Storage and Catalytic Application)

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14 pages, 1796 KiB

Open AccessArticle

Electrochemical Conversion of 5-Hydroxymethylfurfural to 2,5-Furandicarboxaldehyde Using Mn(III)–Schiff Base Catalysts

by Uxía Barreiro-Sisto, Sandra Fernández-Fariña, María Isabel Fernández-García, Ana M. González-Noya, Isabel Velo-Heleno and Marcelino Maneiro

Inorganics 2025, 13(2), 30; https://doi.org/10.3390/inorganics13020030 - 22 Jan 2025

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Abstract

2,5-furandicarboxaldehyde (DFF) is one of the most promising biomass-based building blocks for the synthesis of biobased polymers. DFF can be obtained from 5-hydroxymethylfurfural (HMF), a fructose derivate, and it is a key molecule in the sequence of reactions of furan chemistry to develop [...] Read more.

2,5-furandicarboxaldehyde (DFF) is one of the most promising biomass-based building blocks for the synthesis of biobased polymers. DFF can be obtained from 5-hydroxymethylfurfural (HMF), a fructose derivate, and it is a key molecule in the sequence of reactions of furan chemistry to develop biobased plastics. In this frame, four manganese(III)–Schiff base complexes 1–4 have been obtained. The general formula for the complexes, MnLⁿ(OCN)(H₂O/CH₃OH)_m (Lⁿ being the Schiff base ligands L¹–L⁴, formed as the result of the condensation of different substituted hydroxybenzaldehydes with diverse diamines, and m = 1–3), has been confirmed by characterization through different analytical and spectroscopic techniques. X-ray crystallographic studies for 1 and 2 showed tetragonally distorted octahedral structures, where the Schiff base was placed in the equatorial coordination positions of the Mn(III) ion. Complexes 1 and 2 behaved as efficient catalysts in the oxidation of HMF to DFF in an electrolytic reaction at pH 8.5, with phosphate buffer at room temperature, with conversion rates of 70–80%. On the other hand, complexes 3 and 4, where the axial position was sterically less accessible, yielded only an 11% conversion of HMF to DFF. The results indicate that a correct selection of metal complexes allows the development of a new efficient way to obtain DFF. Full article

(This article belongs to the Special Issue Editorial Board Members’ Collection Series in “Featuring Ligands and Their Applications in Coordination Chemistry”)

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27 pages, 7814 KiB

Open AccessReview

Aluminum-Nitride-Based Semiconductors: Growth Processes, Ferroelectric Properties, and Performance Enhancements

by Luyi Wang, Jinhong Cheng, Ke Qu, Qingfeng Zhu, Bobo Tian and Zhenzhong Yang

Inorganics 2025, 13(2), 29; https://doi.org/10.3390/inorganics13020029 - 21 Jan 2025

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Abstract

Aluminum nitride (AlN)-based ferroelectric films offer significant advantages, including compatibility with CMOS back-end processes, potential for sustainable miniaturization, and intrinsic stability in the ferroelectric phase. As promising emerging materials, they have attracted considerable attention for their broad application potential in nonvolatile ferroelectric memories. [...] Read more.

Aluminum nitride (AlN)-based ferroelectric films offer significant advantages, including compatibility with CMOS back-end processes, potential for sustainable miniaturization, and intrinsic stability in the ferroelectric phase. As promising emerging materials, they have attracted considerable attention for their broad application potential in nonvolatile ferroelectric memories. However, several key scientific and technological challenges remain, including the preparation of single-crystal materials, epitaxial growth, and doping, which hinder their progress in critical ferroelectric devices. To accelerate their development, further research is needed to elucidate the underlying physical mechanisms, such as growth dynamics and ferroelectric properties. This paper provides a comprehensive review of the preparation methods of AlN-based ferroelectric films, covering AlN, Al_1−xSc_xN, Al_1−xB_xN, Y_xAl_1−xN, and Sc_xAl_yGa_1−x−yN. We systematically analyze the similarities, differences, advantages, and limitations of various growth techniques. Furthermore, the ferroelectric properties of AlN and its doped variants are summarized and compared. Strategies for enhancing the ferroelectric performance of AlN-based films are discussed, with a focus on coercive field regulation under stress, suppression of leakage current, fatigue mechanism, and long-term stability. Then, a brief overview of the wide range of applications of AlN-based thin films in electronic and photonic devices is presented. Finally, the challenges associated with the commercialization of AlN-based ferroelectrics are presented, and critical issues for future research are outlined. By synthesizing insights on growth methods, ferroelectric properties, enhancement strategies, and applications, this review aims to facilitate the advancement and practical application of AlN-based ferroelectric materials and devices. Full article

(This article belongs to the Special Issue Nano-Design of Transition Metal Oxides for Energy Storage and Catalytic Application)

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