Inorganics

24 pages, 5158 KiB

Open AccessReview

The Redox Active [2Fe-2S] Clusters: Key-Components of a Plethora of Enzymatic Reactions—Part I: Archaea

by Maddalena Corsini and Piero Zanello

Inorganics 2022, 10(1), 14; https://doi.org/10.3390/inorganics10010014 - 17 Jan 2022

Cited by 1 | Viewed by 3591

The earliest forms of life (i.e., Archaea, Bacteria, and Eukarya) appeared on our planet about ten billion years after its formation. Although Archaea do not seem to possess the multiprotein machinery constituted by the NIF (Nitrogen Fixation), ISC (Iron Sulfur Cluster), SUF (sulfur [...] Read more.

The earliest forms of life (i.e., Archaea, Bacteria, and Eukarya) appeared on our planet about ten billion years after its formation. Although Archaea do not seem to possess the multiprotein machinery constituted by the NIF (Nitrogen Fixation), ISC (Iron Sulfur Cluster), SUF (sulfur mobilization) enzymes, typical of Bacteria and Eukarya, some of them are able to encode Fe-S proteins. Here we discussed the multiple enzymatic reactions triggered by the up-to-date structurally characterized members of the archaeal family that require the crucial presence of structurally characterized [2Fe-2S] assemblies, focusing on their biological functions and, when available, on their electrochemical behavior. Full article

(This article belongs to the Special Issue Assembly and Reactivity of Iron–Sulfur Clusters)

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19 pages, 3156 KiB

Open AccessArticle

Antioxidant and Anticancer Activities and Protein Interaction of the Oxidovanadium(IV) Naringin Complex

by Andrés Gonzalo Restrepo-Guerrero, Helen Goitia-Semenco, Luciana G. Naso, Marilin Rey, Pablo J. Gonzalez, Evelina G. Ferrer and Patricia A. M. Williams

Inorganics 2022, 10(1), 13; https://doi.org/10.3390/inorganics10010013 - 15 Jan 2022

Cited by 6 | Viewed by 2938

Abstract

The complex of oxidovanadium(IV) with naringin (Narg) [VO(Narg)₂] 8H₂O (VONarg) was prepared according to the literature improving the synthetic procedure and physicochemical characterization. In addition, biological activities (cytotoxic, antioxidant, and BSA interaction) were determined. The metal coordinated through the [...] Read more.

The complex of oxidovanadium(IV) with naringin (Narg) [VO(Narg)₂] 8H₂O (VONarg) was prepared according to the literature improving the synthetic procedure and physicochemical characterization. In addition, biological activities (cytotoxic, antioxidant, and BSA interaction) were determined. The metal coordinated through the 5-hydroxy and 4-carbonyl groups of rings A and C of naringin, respectively. The antioxidant activity of VONarg, determined in vitro, was higher than those of the flavonoid against superoxide and peroxyl reactive oxygen species (ROS) and DPPH radical. The cytotoxic properties were determined by a MTT assay on adenocarcinoma human alveolar basal epithelial cells (A549). VONarg exerted a 20% decrease in cancer cells viability at 24 h incubation, while naringin and oxidovanadium(IV) cation did not show cytotoxicity. Measurements with the normal HEK293 cell line showed that the inhibitory action of the complex is selective. VONarg generated intracellular reactive oxygen species (ROS), depletion of reduced glutathione and depolarization of mitochondrial membrane potential, typical for apoptotic pathway, producing cell death by oxidative stress mechanism. Moreover, naringin interacted with bovine serum albumin (BSA) through hydrophobic interactions in a spontaneous process, and VONarg showed greater affinity for the protein but can still be transported and delivered by it (K_a 10⁴ L·mol⁻¹ order). Full article

(This article belongs to the Special Issue New Trends on Vanadium Chemistry, Biochemistry, and Medicinal Chemistry)

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15 pages, 4286 KiB

Open AccessArticle

Bidimensional Polyiodide Netting Stabilized by a Cu(II) Macrocyclic Complex

by Matteo Savastano, Valeria Monini, Carla Bazzicalupi and Antonio Bianchi

Inorganics 2022, 10(1), 12; https://doi.org/10.3390/inorganics10010012 - 13 Jan 2022

Cited by 4 | Viewed by 2762

Abstract

Iodine-dense polyiodide phases are interesting materials for a number of potential uses, including batteries and solid-state conductors. The incorporation of transition metal cations is considered a promising way to enhance the stability, tune the properties, and influence the architecture of polyiodides. However, several [...] Read more.

Iodine-dense polyiodide phases are interesting materials for a number of potential uses, including batteries and solid-state conductors. The incorporation of transition metal cations is considered a promising way to enhance the stability, tune the properties, and influence the architecture of polyiodides. However, several interesting metals, including Cu(II), may suffer redox processes, which generally make them not compatible with the I₂/I⁻ redox couple. Herein L, a simple derivative of cyclen, is proposed as a Cu(II) ligand capable of protecting the +2 oxidation state of the metal even in the presence of polyiodides. With a step by step approach, we report the crystal structure of free L; then we present spectrophotometric verification of Cu(II) complex stability, stoichiometry, and formation kinetic in DMF solution, together with Cu(II) binding mode elucidation via XRD analysis of [Cu(L)Cl]ClO₄∙CH₃CN crystals; afterwards, the stability of the CuL complex in the presence of I⁻ is demonstrated in DMF solution, where the formation of a Cu:L:I⁻ ternary complex, rather than reduction to Cu(I), is observed; lastly, polyiodide crystals are prepared, affording the [Cu(L)I]₂I₃I₅ crystal structure. This layered structure is highly peculiar due to its chiral arrangement, opening further perspective for the crystal engineering of polyiodide phases. Full article

(This article belongs to the Section Coordination Chemistry)

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26 pages, 4123 KiB

Open AccessArticle

Chalcogen···Chalcogen Bonding in Molybdenum Disulfide, Molybdenum Diselenide and Molybdenum Ditelluride Dimers as Prototypes for a Basic Understanding of the Local Interfacial Chemical Bonding Environment in 2D Layered Transition Metal Dichalcogenides

by Pradeep R. Varadwaj, Helder M. Marques, Arpita Varadwaj and Koichi Yamashita

Inorganics 2022, 10(1), 11; https://doi.org/10.3390/inorganics10010011 - 12 Jan 2022

Cited by 9 | Viewed by 3888

Abstract

An attempt was made, using computational methods, to understand whether the intermolecular interactions in the dimers of molybdenum dichalcogenides MoCh₂ (Ch = chalcogen, element of group 16, especially S, Se and Te) and similar mixed-chalcogenide derivatives resemble the room temperature experimentally observed [...] Read more.

An attempt was made, using computational methods, to understand whether the intermolecular interactions in the dimers of molybdenum dichalcogenides MoCh₂ (Ch = chalcogen, element of group 16, especially S, Se and Te) and similar mixed-chalcogenide derivatives resemble the room temperature experimentally observed interactions in the interfacial regions of molybdenites and their other mixed-chalcogen derivatives. To this end, MP2(Full)/def2-TVZPPD level electronic structure calculations on nine dimer systems, including (MoCh₂)₂ and (MoChCh′₂)₂ (Ch, Ch′ = S, Se and Te), were carried out not only to demonstrate the energetic stability of these systems in the gas phase, but also to reproduce the intermolecular geometrical properties that resemble the interfacial geometries of 2D layered MoCh₂ systems reported in the crystalline phase. Among the six DFT functionals (single and double hybrids) benchmarked against MP2(full), it was found that the double hybrid functional B2PLYPD3 has some ability to reproduce the intermolecular geometries and binding energies. The intermolecular geometries and binding energies of all nine dimers are discussed, together with the charge density topological aspects of the chemical bonding interactions that emerge from the application of the quantum theory of atoms in molecules (QTAIM), the isosurface topology of the reduced density gradient noncovalent index, interaction region indicator and independent gradient model (IGM) approaches. While the electrostatic surface potential model fails to explain the origin of the S···S interaction in the (MoS₂)₂ dimer, we show that the intermolecular bonding interactions in all nine dimers examined are a result of hyperconjugative charge transfer delocalizations between the lone-pair on (Ch/Ch′) and/or the π-orbitals of a Mo–Ch/Ch′ bond of one monomer and the d_π* anti-bonding orbitals of the same Mo–Ch/Ch′ bond in the second monomer during dimer formation, and vice versa. The HOMO–LUMO gaps calculated with the MN12-L functional were 0.9, 1.0, and 1.1 eV for MoTe₂, MoSe₂ and MoS₂, respectively, which match very well with the solid-state theoretical (SCAN-rVV10)/experimental band gaps of 0.75/0.88, 0.90/1.09 and 0.93/1.23 eV of the corresponding systems, respectively. We observed that the gas phase dimers examined are perhaps prototypical for a basic understanding of the interfacial/inter-layer interactions in molybdenum-based dichalcogenides and their derivatives. Full article

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13 pages, 4462 KiB

Open AccessArticle

Influence of Ti Substitution on Electrochemical Performance and Evolution of LiMn_1.5−x Ni_0.5Ti_xO₄ (x = 0.05, 0.1, 0.3) as a High Voltage Cathode Material with a Very Long Cycle Life

by Svetlana Niketic, Chae-Ho Yim, Jigang Zhou, Jian Wang and Yaser Abu-Lebdeh

Inorganics 2022, 10(1), 10; https://doi.org/10.3390/inorganics10010010 - 12 Jan 2022

Cited by 2 | Viewed by 2694

Abstract

The high voltage spinel material LiMn_1.5Ni_0.5O₄ (LMNO) has the potential to increase the energy density of lithium batteries. However, its battery performance suffers from poor long-term cycling and high-temperature stability. In order to overcome these limitations, we have [...] Read more.

The high voltage spinel material LiMn_1.5Ni_0.5O₄ (LMNO) has the potential to increase the energy density of lithium batteries. However, its battery performance suffers from poor long-term cycling and high-temperature stability. In order to overcome these limitations, we have studied the effect of partial substitution of Mn with Ti and LiMn_1.5−x Ni_0.5Ti_xO₄ (x = 0.05, 0.1, 0.3), LMNTO, materials have been synthesized in a newly modified sol-gel method and then characterized by TEM, SEM (EDX), AC Electrochemical Impedance Spectroscopy and Soft X-ray Spectromicroscopy. We have demonstrated that the long-term cycling limitation with these types of materials can be resolved and herein 2000 cycles at a high C-rate have been demonstrated in half cells. We have attributed this behavior to a possible charge compensation mechanism as evidenced by a Soft X-ray Spectromicroscopy study of delithiated LMNTO materials. This work takes high energy density batteries based on high voltage spinel material one step further towards commercialization, and it is believed that further improvement can be achieved using new electrolyte formulations. Full article

(This article belongs to the Special Issue A Themed Issue in Honor of Professor Michel Armand on the Occasion of His 75th Birthday)

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11 pages, 4703 KiB

Open AccessArticle

Anisometric Ln(III) Complexes with Efficient Near-IR Luminescence

by Andrey A. Knyazev, Aleksandr S. Krupin and Yuriy G. Galyametdinov

Inorganics 2022, 10(1), 9; https://doi.org/10.3390/inorganics10010009 - 11 Jan 2022

Cited by 1 | Viewed by 2528

Abstract

Recent studies in development of near-infrared luminophores focus on overcoming their disadvantages such as low quantum efficiency, limited emission power, and broad emission spectra. Rare earth (RE) elements are promising compounds in this respect as they offer a unique set of optical properties [...] Read more.

Recent studies in development of near-infrared luminophores focus on overcoming their disadvantages such as low quantum efficiency, limited emission power, and broad emission spectra. Rare earth (RE) elements are promising compounds in this respect as they offer a unique set of optical properties that provide narrow emission spectra and large Stokes shifts. This work reports the results of synthesis and characterization of new anisometric complexes of lanthanide(III) tris(b-diketonates) and 1,10-phenanthroline. These complexes possess light emitting-properties in the near-infrared range. Due to their structural features, these complexes allow production of homogeneous films by spin coating. These films are transparent in the visible and near-infrared ranges (transmission up to 99%). This paper demonstrates advantages of Yb(III), Er(III), and Nd(III) complexes as potential components of highly efficient light-transforming NIR coatings. Full article

(This article belongs to the Special Issue Near-Infrared Luminescent Materials)

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30 pages, 5812 KiB

Open AccessArticle

Aqueous Solution Equilibria and Spectral Features of Copper Complexes with Tripeptides Containing Glycine or Sarcosine and Leucine or Phenylalanine

by Giselle M. Vicatos, Ahmed N. Hammouda, Radwan Alnajjar, Raffaele P. Bonomo, Gabriele Valora, Susan A. Bourne and Graham E. Jackson

Inorganics 2022, 10(1), 8; https://doi.org/10.3390/inorganics10010008 - 10 Jan 2022

Cited by 2 | Viewed by 3751

Abstract

Copper(II) complexes of glycyl-L-leucyl-L-histidine (GLH), sarcosyl-L-leucyl-L-histidine (Sar-LH), glycyl-L-phenylalanyl-L-histidine (GFH) and sarcosyl-L-phenylalanyl-L-histidine (Sar-FH) have potential anti-inflammatory activity, which can help to alleviate the symptoms associated with rheumatoid arthritis (RA). From pH 2–11, the MLH, ML, MLH_-1 and MLH_-2 species formed. The combination [...] Read more.

Copper(II) complexes of glycyl-L-leucyl-L-histidine (GLH), sarcosyl-L-leucyl-L-histidine (Sar-LH), glycyl-L-phenylalanyl-L-histidine (GFH) and sarcosyl-L-phenylalanyl-L-histidine (Sar-FH) have potential anti-inflammatory activity, which can help to alleviate the symptoms associated with rheumatoid arthritis (RA). From pH 2–11, the MLH, ML, MLH_-1 and MLH_-2 species formed. The combination of species for each ligand was different, except at the physiological pH, where CuLH_-2 predominated for all ligands. The prevalence of this species was supported by EPR, ultraviolet-visible spectrophotometry, and mass spectrometry, which suggested a square planar CuN₄ coordination. All ligands have the same basicity for the amine and imidazole-N, but the methyl group of sarcosine decreased the stability of MLH and MLH_-2 by 0.1–0.34 and 0.46–0.48 log units, respectively. Phenylalanine increased the stability of MLH and MLH_-2 by 0.05–0.29 and 1.19–1.21 log units, respectively. For all ligands, ¹H NMR identified two coordination modes for MLH, where copper(II) coordinates via the amine-N and neighboring carbonyl-O, as well as via the imidazole-N and carboxyl-O. EPR spectroscopy identified the MLH, ML and MLH_-2 species for Cu-Sar-LH and suggested a CuN₂O₂ chromophore for ML. DFT calculations with water as a solvent confirmed the proposed coordination modes of each species at the B3LYP level combined with 6-31++G**. Full article

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

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13 pages, 6409 KiB

Open AccessArticle

Novel Fluoridoaluminates from Ammonothermal Synthesis: Two Modifications of K₂AlF₅ and the Elpasolite Rb₂KAlF₆

by Christian Bäucker, Peter Becker, Keshia J. Morell and Rainer Niewa

Inorganics 2022, 10(1), 7; https://doi.org/10.3390/inorganics10010007 - 10 Jan 2022

Cited by 3 | Viewed by 2278

Abstract

Two new modifications of the pentafluoridoaluminate K₂AlF₅ were obtained from ammonothermal synthesis at 753 K, 224 MPa and 773 K, 220 MPa, respectively. Both crystallize in the orthorhombic space group type Pbcn, with close metric relations and feature kinked [...] Read more.

Two new modifications of the pentafluoridoaluminate K₂AlF₅ were obtained from ammonothermal synthesis at 753 K, 224 MPa and 773 K, 220 MPa, respectively. Both crystallize in the orthorhombic space group type Pbcn, with close metric relations and feature kinked chains of cis-vertex-connected AlF₆ octahedra resulting in the Niggli formula

\overset{1}{\infty} {{[{AlF}_{2 / 2}^{e} {F_{4 / 1}}^{t}]}^{2 -}}

. The differences lie in the number of octahedra necessary for repetition within the chains, which for K₂AlF₅-2 is realized after four and for K₂AlF₅-3 after eight octahedra. As a result, the orthorhombic unit cell for K₂AlF₅-3 is doubled in chain prolongation direction [001] as compared to K₂AlF₅-2 (1971.18(4) pm versus 988.45(3) pm, respectively), while the unit cell parameters within the other two directions are virtually identical. Moreover, the new elpasolite Rb₂KAlF₆ is reported, crystallizing in the cubic space group Fm

\bar{3}

m with a = 868.9(1) pm and obtained under ammonothermal conditions at 723 K and 152 MPa. Full article

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

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15 pages, 1155 KiB

Open AccessReview

Probable Reasons for Neuron Copper Deficiency in the Brain of Patients with Alzheimer’s Disease: The Complex Role of Amyloid

by Soghra Bagheri, Ali A. Saboury, Thomas Haertlé, Mauro Rongioletti and Luciano Saso

Inorganics 2022, 10(1), 6; https://doi.org/10.3390/inorganics10010006 - 7 Jan 2022

Cited by 7 | Viewed by 3828

Abstract

Alzheimer’s disease is a progressive neurodegenerative disorder that eventually leads the affected patients to die. The appearance of senile plaques in the brains of Alzheimer’s patients is known as a main symptom of this disease. The plaques consist of different components, and according [...] Read more.

Alzheimer’s disease is a progressive neurodegenerative disorder that eventually leads the affected patients to die. The appearance of senile plaques in the brains of Alzheimer’s patients is known as a main symptom of this disease. The plaques consist of different components, and according to numerous reports, their main components include beta-amyloid peptide and transition metals such as copper. In this disease, metal dyshomeostasis leads the number of copper ions to simultaneously increase in the plaques and decrease in neurons. Copper ions are essential for proper brain functioning, and one of the possible mechanisms of neuronal death in Alzheimer’s disease is the copper depletion of neurons. However, the reason for the copper depletion is as yet unknown. Based on the available evidence, we suggest two possible reasons: the first is copper released from neurons (along with beta-amyloid peptides), which is deposited outside the neurons, and the second is the uptake of copper ions by activated microglia. Full article

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51 pages, 12095 KiB

Open AccessReview

Remedies to Avoid Failure Mechanisms of Lithium-Metal Anode in Li-Ion Batteries

by Alain Mauger and Christian M. Julien

Inorganics 2022, 10(1), 5; https://doi.org/10.3390/inorganics10010005 - 31 Dec 2021

Cited by 4 | Viewed by 6914

Abstract

Rechargeable lithium-metal batteries (LMBs), which have high power and energy density, are very attractive to solve the intermittence problem of the energy supplied either by wind mills or solar plants or to power electric vehicles. However, two failure modes limit the commercial use [...] Read more.

Rechargeable lithium-metal batteries (LMBs), which have high power and energy density, are very attractive to solve the intermittence problem of the energy supplied either by wind mills or solar plants or to power electric vehicles. However, two failure modes limit the commercial use of LMBs, i.e., dendrite growth at the surface of Li metal and side reactions with the electrolyte. Substantial research is being accomplished to mitigate these drawbacks. This article reviews the different strategies for fabricating safe LMBs, aiming to outperform lithium-ion batteries (LIBs). They include modification of the electrolyte (salt and solvents) to obtain a highly conductive solid–electrolyte interphase (SEI) layer, protection of the Li anode by in situ and ex situ coatings, use of three-dimensional porous skeletons, and anchoring Li on 3D current collectors. Full article

(This article belongs to the Special Issue A Themed Issue in Honor of Professor Michel Armand on the Occasion of His 75th Birthday)

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16 pages, 1984 KiB

Open AccessArticle

Phenanthroline Complexation Enhances the Cytotoxic Activity of the VO-Chrysin System

by Agustin Actis Dato, Luciana G. Naso, Marilin Rey, Pablo J. Gonzalez, Evelina G. Ferrer and Patricia A. M. Williams

Inorganics 2022, 10(1), 4; https://doi.org/10.3390/inorganics10010004 - 28 Dec 2021

Cited by 3 | Viewed by 2634

Abstract

Metal complexation in general improves the biological properties of ligands. We have previously measured the anticancer effects of the oxidovanadium(IV) cation with chrysin complex, VO(chrys)₂. In the present study, we synthesized and characterized a new complex generated by the replacement of [...] Read more.

Metal complexation in general improves the biological properties of ligands. We have previously measured the anticancer effects of the oxidovanadium(IV) cation with chrysin complex, VO(chrys)₂. In the present study, we synthesized and characterized a new complex generated by the replacement of one chrysin ligand by phenanthroline (phen), VO(chrys)phenCl, to confer high planarity for DNA chain intercalation and more lipophilicity, giving rise to a better cellular uptake. In effect, the uptake of vanadium has been increased in the complex with phen and the cytotoxic effect of this complex proved higher in the human lung cancer A549 cell line, being involved in its mechanisms of action, the production of cellular reactive oxygen species (ROS), the decrease of the natural antioxidant compound glutathione (GSH) and the ratio GSH/GSSG (GSSG, oxidized GSH), and mitochondrial membrane damage. Cytotoxic activity studies using the non-tumorigenic HEK293 cell line showed that [VO(chrys)phenCl] exhibits selectivity action towards A549 cells after 24 h incubation. The interaction with bovine serum albumin (BSA) by fluorometric determinations showed that the complex could be carried by the protein and that the binding of the complex to BSA occurs through H-bond and van der Waals interactions. Full article

(This article belongs to the Special Issue New Trends on Vanadium Chemistry, Biochemistry, and Medicinal Chemistry)

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16 pages, 2182 KiB

Open AccessArticle

Synthesis and Characterization of Novel Copper(II)-Sunitinib Complex: Molecular Docking, DFT Studies, Hirshfeld Analysis and Cytotoxicity Studies

by Facundo Tarasi, Priscila Ailín Lanza, Valeria Ferretti, Gustavo Alberto Echeverría, Oscar Enrique Piro, Maximiliano Cacicedo, Stephan Gehring, Ignacio Esteban León and María Soledad Islas

Inorganics 2022, 10(1), 3; https://doi.org/10.3390/inorganics10010003 - 22 Dec 2021

Cited by 3 | Viewed by 3279

Abstract

The main goal of this work was to report the synthesis, characterization, and cytotoxicity study of a novel copper(II)-sunitinib complex, CuSun. It has been synthesized and characterized in solid state and in solution by different methods (such as DFT, FTIR, Raman, UV-vis, EPR, [...] Read more.

The main goal of this work was to report the synthesis, characterization, and cytotoxicity study of a novel copper(II)-sunitinib complex, CuSun. It has been synthesized and characterized in solid state and in solution by different methods (such as DFT, FTIR, Raman, UV-vis, EPR, NMR, etc.). The solid-state molecular structure of trichlorosunitinibcopper(II), where sunitinib: N-[2-(diethylamino)ethyl]-5-[(Z)-(5-fluoro-2-oxo-1H-indol-3-ylidene)methyl]-2,4-dimethyl-1H-pyrrole-3-carboxamide, for short Cu(Sun)Cl₃, was determined by X-ray diffraction. It crystallizes in the triclinic space group P-1 with a = 7.9061(5) Å, b = 12.412(1) Å, c = 13.7005(8) Å, α = 105.021(6)°, β = 106.744(5)°, γ = 91.749(5)°, and Z = 2 molecules per unit cell. Also, we have found π-π interactions and classic and non-classic H-bonds in the crystal structure by using Hirshfeld surface analysis. In the speciation studies, the complex has dissociated in protonated sunitinib and chlorocomplex of copper(II), according to ¹HNMR, EPR, UV-vis and conductimetric analysis. Molecular docking of the complex in both, ATP binding site and allosteric site of VEGFR2 have shown no improvement in comparison to the free ligand. Besides, cytotoxicity assay on HepG2 cell line shows similar activity for complex and ligand in the range between 1–25 μM supporting the data obtained from studies in solution. Full article

(This article belongs to the Special Issue Metal-Based Anticancer Drugs)

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15 pages, 2601 KiB

Open AccessArticle

Prediction of the Iron–Sulfur Binding Sites in Proteins Using the Highly Accurate Three-Dimensional Models Calculated by AlphaFold and RoseTTAFold

by Béatrice Golinelli-Pimpaneau

Inorganics 2022, 10(1), 2; https://doi.org/10.3390/inorganics10010002 - 22 Dec 2021

Cited by 10 | Viewed by 5255

Abstract

AlphaFold and RoseTTAFold are deep learning-based approaches that predict the structure of proteins from their amino acid sequences. Remarkable success has recently been achieved in the prediction accuracy of not only the fold of the target protein but also the position of its [...] Read more.

AlphaFold and RoseTTAFold are deep learning-based approaches that predict the structure of proteins from their amino acid sequences. Remarkable success has recently been achieved in the prediction accuracy of not only the fold of the target protein but also the position of its amino acid side chains. In this article, I question the accuracy of these methods to predict iron–sulfur binding sites. I analyze three-dimensional models calculated by AlphaFold and RoseTTAFold of Fe–S–dependent enzymes, for which no structure of a homologous protein has been solved experimentally. In all cases, the amino acids that presumably coordinate the cluster were gathered together and facing each other, which led to a quite accurate model of the Fe–S cluster binding site. Yet, cysteine candidates were often involved in intramolecular disulfide bonds, and the number and identity of the protein amino acids that should ligate the cluster were not always clear. The experimental structure determination of the protein with its Fe–S cluster and in complex with substrate/inhibitor/product is still needed to unambiguously visualize the coordination state of the cluster and understand the conformational changes occurring during catalysis. Full article

(This article belongs to the Special Issue Assembly and Reactivity of Iron–Sulfur Clusters)

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14 pages, 4352 KiB

Open AccessArticle

Waste-to-Reuse Foam Glasses Produced from Soda-Lime-Silicate Glass, Cathode Ray Tube Glass, and Aluminium Dross

by Meriem Sassi and Andrea Simon

Inorganics 2022, 10(1), 1; https://doi.org/10.3390/inorganics10010001 - 21 Dec 2021

Cited by 11 | Viewed by 3429

Abstract

Aluminium dross is a hazardous industrial waste generated during aluminium production. It contains metallic oxides of aluminium and magnesium, other phases (aluminum nitride), and residues of fluxes and salts from the melting process of aluminium. Discarding this by-product is considered an environmental and [...] Read more.

Aluminium dross is a hazardous industrial waste generated during aluminium production. It contains metallic oxides of aluminium and magnesium, other phases (aluminum nitride), and residues of fluxes and salts from the melting process of aluminium. Discarding this by-product is considered an environmental and economic challenge due to the high reactivity of dross with water or even air humidity. After removing the hazardous components from the as-received dross, one of the optional approaches is to incorporate the treated dross into construction materials. Dross is applied in several types of research as a secondary raw material source for alumina, clinker, cement or glass-ceramic production, but only a few papers focus on the usage of dross as a foaming agent for foams. Even fewer research are reported where dross was applied as a basic component of foam glasses. In this work, foam glasses were produced completely from waste materials: Aluminium dross, container (SLS) glass, and cathode ray tube (CRT) glass. The research holds several specificities, i.e., combining two industrial waste materials (CRT glass and dross), and adding an increased amount from the wastes. The physical and mechanical characteristics were examined with a special focus on the effect of the foam glass components on the microstructure, density, thermal conductivity, and compressive strength. Full article

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Inorganics, Volume 10, Issue 1 (January 2022) – 14 articles

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