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Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Inorganic Chemistry".

Deadline for manuscript submissions: 31 December 2024 | Viewed by 40303

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Department of Chemistry, University of Florence, Via della Lastruccia, 3-13, 50019 Sesto Fiorentino, Firenze, Italy
Interests: synthetic inorganic chemistry; coordination chemistry; polyamine ligands; anion coordination; supramolecular chemistry; weak interactions; coordination of toxic metals and anions; reactive oxygen species (ROS); ROS generation/scavenging by metals and their complexes
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Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cagliari, Italy
Interests: coordination chemistry of macrocyclic ligands; fluorescent molecular sensors for metal ion and anions; selenium and tellurium containing molecules; crystal engineering; coordination polymers
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Special Issue Information

Dear Colleagues,

It is our pleasure to announce a new Special Issue entitled “Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition”. This is a collection of important high-quality papers (original research articles or comprehensive review papers) published in open access format by Editorial Board Members or prominent scholars invited by the Editorial Office and the Guest Editors. This Special Issue aims to discuss new knowledge or new cutting-edge developments in the inorganic chemistry research field through selected works, in the hope of making a great contribution to the community. We intend for this Issue to be the best forum for disseminating excellent research findings as well as sharing innovative ideas in the field.

Dr. Andrea Bencini
Prof. Dr. Vito Lippolis
Guest Editors

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Published Papers (32 papers)

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11 pages, 593 KiB  
Article
Relaxivity Modulation of Gd-HPDO3A-like Complexes by Introducing Polar and Protic Peripheral Groups
by Sara Camorali, Loredana Leone, Laura Piscopo and Lorenzo Tei
Molecules 2024, 29(19), 4663; https://doi.org/10.3390/molecules29194663 - 30 Sep 2024
Abstract
In the last three decades, high-relaxivity Magnetic Resonance Imaging (MRI) contrast agents (CAs) have been intensively sought, aiming at a reduction in the clinically injected dose while maintaining the safety of the CA and obtaining the same pathological information. Thus, four new Gd(III) [...] Read more.
In the last three decades, high-relaxivity Magnetic Resonance Imaging (MRI) contrast agents (CAs) have been intensively sought, aiming at a reduction in the clinically injected dose while maintaining the safety of the CA and obtaining the same pathological information. Thus, four new Gd(III) complexes based on modified 10-(2-hydroxypropyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (HP-DO3A) macrocyclic structure were designed and synthesized by introducing further polar and protic functional groups (amides, phosphonates, and diols) adjacent to the metal-coordinated hydroxyl group. A detailed 1H NMR relaxometric analysis allowed us to investigate the effect of these functional groups on the relaxivity, which showed a 20–60% increase (at 0.5 T, 298 K, and pH 7.4) with respect to that of clinically approved CAs. The contribution of the water molecules H-bonded to these peripheral functional groups on the relaxivity was evaluated in terms of the second sphere effect or prototropic exchange of labile protons. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
18 pages, 3424 KiB  
Article
Large Number of Direct or Pseudo-Direct Band Gap Semiconductors among A3TrPn2 Compounds with A = Li, Na, K, Rb, Cs; Tr = Al, Ga, In; Pn = P, As
by Sabine Zeitz, Yulia Kuznetsova and Thomas F. Fässler
Molecules 2024, 29(17), 4087; https://doi.org/10.3390/molecules29174087 - 28 Aug 2024
Viewed by 335
Abstract
Due to the high impact of semiconductors with respect to many applications for electronics and energy transformation, the search for new compounds and a deep understanding of the structure–property relationship in such materials has a high priority. Electron-precise Zintl compounds of the composition [...] Read more.
Due to the high impact of semiconductors with respect to many applications for electronics and energy transformation, the search for new compounds and a deep understanding of the structure–property relationship in such materials has a high priority. Electron-precise Zintl compounds of the composition A3TrPn2 (A = Li − Cs, Tr = Al − In, Pn = P, As) have been reported for 22 possible element combinations and show a large variety of different crystal structures comprising zero-, one-, two- and three-dimensional polyanionic substructures. From Li to Cs, the compounds systematically lower the complexity of the anionic structure. For an insight into possible crystal–structure band–structure relations for all compounds (experimentally known or predicted), their band structures, density of states and crystal orbital Hamilton populations were calculated on a basis of DFT/PBE0 and SVP/TZVP basis sets. All but three (Na3AlP2, Na3GaP2 and Na3AlAs2) compounds show direct or pseudo-direct band gaps. Indirect band gaps seem to be linked to one specific structure type, but only for Al and Ga compounds. Arsenides show smaller band gaps than phosphides due to weaker Tr-As bonds. The bonding situation was confirmed by a Mullikan analysis, and most states close to the Fermi level were assigned to non-bonding orbitals. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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24 pages, 7874 KiB  
Article
A Mechanistic Study on Iron-Based Styrene Aziridination: Understanding Epoxidation via Nitrene Hydrolysis
by Dóra Lakk-Bogáth, Patrik Török, Dénes Pintarics and József Kaizer
Molecules 2024, 29(15), 3470; https://doi.org/10.3390/molecules29153470 - 24 Jul 2024
Viewed by 570
Abstract
Transition-metal-catalyzed nitrene transfer reactions are typically performed in organic solvents under inert and anhydrous conditions due to the involved air and water-sensitive nature of reactive intermediates. Overall, this study provides insights into the iron-based ([FeII(PBI)3](CF3SO3) [...] Read more.
Transition-metal-catalyzed nitrene transfer reactions are typically performed in organic solvents under inert and anhydrous conditions due to the involved air and water-sensitive nature of reactive intermediates. Overall, this study provides insights into the iron-based ([FeII(PBI)3](CF3SO3)2 (1), where PBI = 2-(2-pyridyl)benzimidazole), catalytic and stoichiometric aziridination of styrenes using PhINTs ([(N-tosylimino)iodo]benzene), highlighting the importance of reaction conditions including the effects of the solvent, co-ligands (para-substituted pyridines), and substrate substituents on the product yields, selectivity, and reaction kinetics. The aziridination reactions with 1/PhINTs showed higher conversion than epoxidation with 1/PhIO (iodosobenzene). However, the reaction with PhINTs was less selective and yielded more products, including styrene oxide, benzaldehyde, and 2-phenyl-1-tosylaziridine. Therefore, the main aim of this study was to investigate the potential role of water in the formation of oxygen-containing by-products during radical-type nitrene transfer catalysis. During the catalytic tests, a lower yield was obtained in a protic solvent (trifluoroethanol) than in acetonitrile. In the case of the catalytic oxidation of para-substituted styrenes containing electron-donating groups, higher yield, TON, and TOF were achieved than those with electron-withdrawing groups. Pseudo-first-order kinetics were observed for the stoichiometric oxidation, and the second-order rate constants (k2 = 7.16 × 10−3 M−1 s−1 in MeCN, 2.58 × 10−3 M−1 s−1 in CF3CH2OH) of the reaction were determined. The linear free energy relationships between the relative reaction rates (logkrel) and the total substituent effect (TE, 4R-PhCHCH2) parameters with slopes of 1.48 (MeCN) and 1.89 (CF3CH2OH) suggest that the stoichiometric aziridination of styrenes can be described through the formation of a radical intermediate in the rate-determining step. Styrene oxide formation during aqueous styrene aziridination most likely results from oxygen atom transfer via in situ iron oxo/oxyl radical complexes, which are formed through the hydrolysis of [FeIII(N•Ts)] under experimental conditions. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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10 pages, 1739 KiB  
Article
Tuning the Coordination Environment of Ru(II) Complexes with a Tailored Acridine Ligand
by Ali Awada, Pierre-Henri Lanoë, Christian Philouze, Frédérique Loiseau and Damien Jouvenot
Molecules 2024, 29(15), 3468; https://doi.org/10.3390/molecules29153468 - 24 Jul 2024
Viewed by 529
Abstract
A novel tridentate ligand featuring an acridine core and pyrazole rings, namely 2,7- di-tert-butyl-4,5-di(pyrazol-1-yl)acridine, L, was designed and used to create two ruthenium(II) complexes: [RuL2](PF6)2 and [Ru(tpy)L](PF6)2. Surprisingly, [...] Read more.
A novel tridentate ligand featuring an acridine core and pyrazole rings, namely 2,7- di-tert-butyl-4,5-di(pyrazol-1-yl)acridine, L, was designed and used to create two ruthenium(II) complexes: [RuL2](PF6)2 and [Ru(tpy)L](PF6)2. Surprisingly, the ligand adopted different coordination modes in the complexes: facial coordination for the homoleptic complex and meridional coordination for the heteroleptic complex. The electronic absorption and electrochemical properties were evaluated. Although both complexes exhibited favorable electronic properties for luminescence, neither emitted light at room temperature nor at 77 K. This study highlights the complex interplay between ligand design, coordination mode, and luminescence in ruthenium(II) complexes. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 1918 KiB  
Article
Assembly of Homochiral Magneto-Optical Dy6 Triangular Clusters by Fixing Carbon Dioxide in the Air
by Cai-Ming Liu, Xiang Hao and Xi-Li Li
Molecules 2024, 29(14), 3402; https://doi.org/10.3390/molecules29143402 - 19 Jul 2024
Cited by 1 | Viewed by 827
Abstract
A new hydrazone Schiff base bridging ligand (H2LSchiff (E)-N′-((1-hydroxynaphthalen-2-yl)methylene)pyrazine-2-carbohydrazide) and L/D-proline were used to construct a pair of homochiral Dy6 cluster complexes, [Dy6(CO3)(L-Pro)6(LSchiff [...] Read more.
A new hydrazone Schiff base bridging ligand (H2LSchiff (E)-N′-((1-hydroxynaphthalen-2-yl)methylene)pyrazine-2-carbohydrazide) and L/D-proline were used to construct a pair of homochiral Dy6 cluster complexes, [Dy6(CO3)(L-Pro)6(LSchiff)4(HLSchiff)2]·5DMA·2H2O (L-1, L-HPro = L-proline; DMA = N,N-dimethylacetamide) and [Dy6(CO3)(D-Pro)6(LSchiff)4(HLSchiff)2]·5DMA·2H2O (D-1, D-HPro = D-proline), which show a novel triangular Dy6 topology. Notably, the fixation of CO2 in the air formed a carbonato central bridge, playing a key role in assembling L-1/D-1. Magnetic measurements revealed that L-1/D-1 displays intramolecular ferromagnetic coupling and magnetic relaxation behaviours. Furthermore, L-1/D-1 shows a distinct magneto-optical Faraday effect and has a second harmonic generation (SHG) response (1.0 × KDP) at room temperature. The results show that the immobilization of CO2 provides a novel pathway for homochiral multifunctional 4f cluster complexes. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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18 pages, 5147 KiB  
Article
Electrocatalytic Properties of Quasi-2D Oxides LaSrMn0.5M0.5O4 (M = Co, Ni, Cu, and Zn) for Hydrogen and Oxygen Evolution Reactions
by Kinithi M. K. Wickramaratne and Farshid Ramezanipour
Molecules 2024, 29(13), 3107; https://doi.org/10.3390/molecules29133107 - 29 Jun 2024
Viewed by 524
Abstract
Designing cost-effective and highly efficient electrocatalysts for water splitting is a significant challenge. We have systematically investigated a series of quasi-2D oxides, LaSrMn0.5M0.5O4 (M = Co, Ni, Cu, Zn), to enhance the electrocatalytic properties of the two half-reactions [...] Read more.
Designing cost-effective and highly efficient electrocatalysts for water splitting is a significant challenge. We have systematically investigated a series of quasi-2D oxides, LaSrMn0.5M0.5O4 (M = Co, Ni, Cu, Zn), to enhance the electrocatalytic properties of the two half-reactions of water-splitting, namely oxygen and hydrogen evolution reactions (OER and HER). The four materials are isostructural, as confirmed by Rietveld refinements with X-ray diffraction. The oxygen contents and metal valence states were determined by iodometric titrations and X-ray photoelectron spectroscopy. Electrical conductivity measurements in a wide range of temperatures revealed semiconducting behavior for all four materials. Electrocatalytic properties were studied for both half-reactions of water-splitting, namely, oxygen-evolution and hydrogen-evolution reactions (OER and HER). For the four materials, the trends in both OER and HER were the same, which also matched the trend in electrical conductivities. Among them, LaSrMn0.5Co0.5O4 showed the best bifunctional electrocatalytic activity for both OER and HER, which may be attributed to its higher electrical conductivity and favorable electron configuration. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 2030 KiB  
Article
Ab Initio Electronic, Magnetic, and Optical Properties of Fe Phthalocyanine on Cr2O3(0001)
by Marco Marino, Elena Molteni, Simona Achilli, Giovanni Onida and Guido Fratesi
Molecules 2024, 29(12), 2889; https://doi.org/10.3390/molecules29122889 - 18 Jun 2024
Viewed by 513
Abstract
The organic molecules adsorbed on antiferromagnetic surfaces can produce interesting interface states, characterized by charge transfer mechanisms, hybridization of molecular-substrate orbitals, as well as magnetic couplings. Here, we apply an ab initio approach to study the adsorption of Fe phthalocyanine on stoichiometric Cr [...] Read more.
The organic molecules adsorbed on antiferromagnetic surfaces can produce interesting interface states, characterized by charge transfer mechanisms, hybridization of molecular-substrate orbitals, as well as magnetic couplings. Here, we apply an ab initio approach to study the adsorption of Fe phthalocyanine on stoichiometric Cr2O3(0001). The molecule binds via a bidentate configuration forming bonds between two opposite imide N atoms and two protruding Cr ones, making this preferred over the various possible adsorption structures. In addition to the local modifications at these sites, the electronic structure of the molecule is weakly influenced. The magnetic structure of the surface Cr atoms shows a moderate influence of molecule adsorption, not limited to the atoms in the close proximity of the molecule. Upon optical excitation at the onset, electron density moves toward the molecule, enhancing the ground state charge transfer. We investigate this movement of charge as a mechanism at the base of light-induced modifications of the magnetic structure at the interface. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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11 pages, 981 KiB  
Article
Cobalt(III)–Macrocyclic Scaffolds with Anti-Cancer Stem Cell Activity
by Jiaxin Fang, Philipp Gerschel, Kuldip Singh, Ulf-Peter Apfel and Kogularamanan Suntharalingam
Molecules 2024, 29(12), 2743; https://doi.org/10.3390/molecules29122743 - 8 Jun 2024
Viewed by 619
Abstract
Cobalt(III) compounds with tetradentate ligands have been widely employed to deliver cytotoxic and imaging agents into cells. A large body of work has focused on using cobalt(III)–cyclam scaffolds for this purpose. Here, we investigate the cytotoxic properties of cobalt(III) complexes containing 14-membered macrocycles [...] Read more.
Cobalt(III) compounds with tetradentate ligands have been widely employed to deliver cytotoxic and imaging agents into cells. A large body of work has focused on using cobalt(III)–cyclam scaffolds for this purpose. Here, we investigate the cytotoxic properties of cobalt(III) complexes containing 14-membered macrocycles related to cyclam. A breast cancer stem cell (CSC) in vitro model was used to gauge efficacy. Specifically, [Co(1,4,7,11-tetraazacyclotetradecane)Cl2]+ (1) and [Co(1-oxa-4,8,12-triazacyclotetradecane)Cl2]+ (2) were synthesised and characterised, and their breast CSC activity was determined. The cobalt(III) complexes 1 and 2 displayed micromolar potency towards bulk breast cancer cells and breast CSCs grown in monolayers. Notably, 1 and 2 displayed selective potency towards breast CSCs over bulk breast cancer cells (up to 4.5-fold), which was similar to salinomycin (an established breast CSC-selective agent). The cobalt(III) complexes 1 and 2 were also able to inhibit mammosphere formation at low micromolar doses (with respect to size and number). The mammopshere inhibitory effect of 2 was similar to that of salinomycin. Our studies show that cobalt(III) complexes with 1,4,7,11-tetraazacyclotetradecane and 1-oxa-4,8,12-triazacyclotetradecane macrocycles could be useful starting points for the development of new cobalt-based delivery systems that can transport cytotoxic and imaging agents into breast CSCs. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 3444 KiB  
Article
Bimetallic Perthiocarbonate Complexes of Cobalt: Synthesis, Structure and Bonding
by Alaka Nanda Pradhan, Shivankan Mishra, Urminder Kaur, Bikram Keshari Rout, Jean-François Halet and Sundargopal Ghosh
Molecules 2024, 29(11), 2688; https://doi.org/10.3390/molecules29112688 - 6 Jun 2024
Viewed by 678
Abstract
The syntheses and structural elucidation of bimetallic thiolate complexes of early and late transition metals are described. Thermolysis of the bimetallic hydridoborate species [{Cp*CoPh}{µ-TePh}{µ-TeBH3-ĸ2Te,H}{Cp*Co}] (Cp* = ɳ5-C5Me5) ( [...] Read more.
The syntheses and structural elucidation of bimetallic thiolate complexes of early and late transition metals are described. Thermolysis of the bimetallic hydridoborate species [{Cp*CoPh}{µ-TePh}{µ-TeBH3-ĸ2Te,H}{Cp*Co}] (Cp* = ɳ5-C5Me5) (1) in the presence of CS2 afforded the bimetallic perthiocarbonate complex [(Cp*Co)2(μ-CS4-κ1S:κ2S′)(μ-S2-κ2S″:κ1S‴)] (2) and the dithiolene complex [(Cp*Co)(μ-C3S5-κ1S,S′] (3). Complex 2 contains a four-membered metallaheterocycle (Co2S2) comprising a perthiocarbonate [CS4]2− unit and a disulfide [S2]2− unit, attached opposite to each other. Complex 2 was characterized by employing different multinuclear NMR, infrared spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies. Preliminary studies show that [Cp*VCl2]3 (4) with an intermediate generated from CS2 and [LiBH4·THF] yielded thiolate species, albeit different from the cobalt system. Furthermore, a computational analysis was performed to provide insight into the bonding of this bimetallic perthiocarbonate complex. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 5726 KiB  
Article
Gallium Trichloride Fluid: Dimer Dissociation Mechanism, Local Structure, and Atomic Dynamics
by Maxim Khomenko, Anton Sokolov, Andrey Tverjanovich, Maria Bokova, Mohammad Kassem, Takeshi Usuki and Eugene Bychkov
Molecules 2024, 29(6), 1358; https://doi.org/10.3390/molecules29061358 - 19 Mar 2024
Viewed by 819
Abstract
Molten gallium trichloride emerges as a promising solvent for oxidative metal recycling. The use of supercritical fluid enhances the performance and kinetics of metal dissolution due to significantly lower viscosity in the reaction media. Additionally, the dual molecular nature of gallium trichloride, existing [...] Read more.
Molten gallium trichloride emerges as a promising solvent for oxidative metal recycling. The use of supercritical fluid enhances the performance and kinetics of metal dissolution due to significantly lower viscosity in the reaction media. Additionally, the dual molecular nature of gallium trichloride, existing as edge-sharing ES-Ga2Cl6 dimers at low temperatures and high pressure, or flat trigonal GaCl3 monomers in the vicinity of the critical point and low pressures, creates the possibility to tailor the chemical geometry to a particular metallic species. Nevertheless, the mechanism of dimer dissociation, local structure, and atomic dynamics in supercritical gallium trichloride fluids are not known. Using first-principles molecular dynamics, validated by comparison with our high-energy X-ray diffraction results, we illustrate the elementary steps in dimer dissociation. These include the formation of intermediate corner-sharing CS-Ga2Cl6 dimers, the partial disproportionation of GaCl3 monomers at high temperatures and low pressures, changes in the local environment of molecular entities, and unusual atomic dynamics in supercritical fluids. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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10 pages, 2445 KiB  
Article
Synthesis of Alkenylgold(I) Complexes Relevant to Catalytic Carboxylative Cyclization of Unsaturated Amines and Alcohols
by Shun Hase, Kyohei Yamashita and Yoshihito Kayaki
Molecules 2024, 29(6), 1331; https://doi.org/10.3390/molecules29061331 - 16 Mar 2024
Viewed by 984
Abstract
The carboxylation of unsaturated amine and alcohol compounds, including 4-benzylamino-1-phenyl-1-butyne (homopropargylamine), 2-butyne-1-ol (propargylic alcohol), and 2,3-butadiene-1-ol (allenylmethyl alcohol), using the hydroxidogold(I) complex, AuOH(IPr) [IPr = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene], produces corresponding alkenylgold(I) complexes with a cyclic urethane or carbonate framework in high yields. The reaction takes [...] Read more.
The carboxylation of unsaturated amine and alcohol compounds, including 4-benzylamino-1-phenyl-1-butyne (homopropargylamine), 2-butyne-1-ol (propargylic alcohol), and 2,3-butadiene-1-ol (allenylmethyl alcohol), using the hydroxidogold(I) complex, AuOH(IPr) [IPr = 1,3-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene], produces corresponding alkenylgold(I) complexes with a cyclic urethane or carbonate framework in high yields. The reaction takes place in aprotic THF at room temperature under the atmospheric pressure of CO2 in the absence of base additives. The products were characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. The functionalized alkenyl complexes prepared from the alkynes can be protonated by treatment with an equimolar amount of acetic acid to afford five- or six-membered carboxylation products, whereas the related alkenyl complex derived from allenylmethyl alcohol decomposed to recover the starting allene via ring-opening decarboxylation. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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18 pages, 3579 KiB  
Article
Metal Complexes Containing Homoleptic Diorganoselenium(II) Ligands: Synthesis, Characterization and Investigation of Optical Properties
by Darius Dumitraș, Emese Gal, Cristian Silvestru and Alexandra Pop
Molecules 2024, 29(4), 792; https://doi.org/10.3390/molecules29040792 - 8 Feb 2024
Viewed by 955
Abstract
[(Z)-2′-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (5, L1) and [(Z)-4′-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (6, L [...] Read more.
[(Z)-2′-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (5, L1) and [(Z)-4′-{2-C6H5-(4H)-oxazol-5-one}CHC6H4]2Se (6, L2) were prepared, structurally characterized and used as ligands to obtain new metal complexes of types [MX(Ln)] [L1: M = Ag, X = OTf (7); M = Au, X = Cl (13); L2: M = Ag, X = OTf (8); M = Au, X = Cl (14)], [(MX)2(Ln)] [M = Ag, X = OTf, L1 (9); L2 (10)], [ZnCl2(Ln)] [L1 (15); L2 (16)] and [Ag(Ln)][PF6] [L1 (11); L2 (12)]. The silver complexes 7 and 8 were ionic species (1:1 electrolytes) in a MeCN solution, while in the solid state, the triflate fragments were bonded to the silver cations. Similarly, the 2:1 complexes 9 and 10 were found to behave as 1:2 electrolytes in a MeCN solution, but single-crystal X-ray diffraction demonstrated that compound 9 showed the formation of a dimer in the solid state: a tetranuclear [Ag(OTf)]4 built through bridging triflate ligands was coordinated by two bridging organoselenium ligands through the nitrogen from the oxazolone ring and the selenium atoms in a 1κN:2κSe fashion. Supramolecular architectures supported by intermolecular C−H∙∙∙π, C−H∙∙∙O, Cl∙∙∙H and F∙∙∙H interactions were observed in compounds 4, 5 and 9. The compounds exhibited similar photophysical properties, with a bathochromic shift in the UV-Vis spectra caused by the position of the oxazolone ring on the phenyl ring attached to the selenium atoms. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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15 pages, 2985 KiB  
Article
New Stable Gallium(III) and Indium(III) Complexes with Thiosemicarbazone Ligands: A Biological Evaluation
by Lorenzo Verderi, Mirco Scaccaglia, Martina Rega, Cristina Bacci, Silvana Pinelli, Giorgio Pelosi and Franco Bisceglie
Molecules 2024, 29(2), 497; https://doi.org/10.3390/molecules29020497 - 19 Jan 2024
Cited by 1 | Viewed by 1668
Abstract
The aim of this work is to explore a new library of coordination compounds for medicinal applications. Gallium is known for its various applications in this field. Presently, indium is not particularly important in medicine, but it shares a lot of chemical traits [...] Read more.
The aim of this work is to explore a new library of coordination compounds for medicinal applications. Gallium is known for its various applications in this field. Presently, indium is not particularly important in medicine, but it shares a lot of chemical traits with its above-mentioned lighter companion, gallium, and is also used in radio imaging. These metals are combined with thiosemicarbazones, ligating compounds increasingly known for their biological and pharmaceutical applications. In particular, the few ligands chosen to interact with these hard metal ions share the ideal affinity for a high charge density. Therefore, in this work we describe the synthesis and the characterization of the resulting coordination compounds. The yields of the reactions vary from a minimum of 21% to a maximum of 82%, using a fast and easy procedure. Nuclear Magnetic Resonance (NMR) and Infra Red (IR) spectroscopy, mass spectrometry, elemental analysis, and X-ray Diffraction (XRD) confirm the formation of stable compounds in all cases and a ligand-to-metal 2:1 stoichiometry with both cations. In addition, we further investigated their chemical and biological characteristics, via UV-visible titrations, stability tests, and cytotoxicity and antibiotic assays. The results confirm a strong stability in all explored conditions, which suggests that these compounds are more suitable for radio imaging applications rather than for antitumoral or antimicrobic ones. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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16 pages, 3688 KiB  
Article
Aluminium 8-Hydroxyquinolinate N-Oxide as a Precursor to Heterometallic Aluminium–Lanthanide Complexes
by Elisa Gallo, Luca Bellucci, Silvia Carlotto, Gregorio Bottaro, Luca Babetto, Luca Giordano, Fabio Marchetti, Simona Samaritani, Lidia Armelao and Luca Labella
Molecules 2024, 29(2), 451; https://doi.org/10.3390/molecules29020451 - 17 Jan 2024
Cited by 2 | Viewed by 1661
Abstract
A reaction in anhydrous toluene between the formally unsaturated fragment [Ln(hfac)3] (Ln3+ = Eu3+, Gd3+ and Er3+; Hhfac = hexafluoroacetylacetone) and [Al(qNO)3] (HqNO = 8-hydroxyquinoline N-oxide), here prepared for the first time [...] Read more.
A reaction in anhydrous toluene between the formally unsaturated fragment [Ln(hfac)3] (Ln3+ = Eu3+, Gd3+ and Er3+; Hhfac = hexafluoroacetylacetone) and [Al(qNO)3] (HqNO = 8-hydroxyquinoline N-oxide), here prepared for the first time from [Al(OtBu)3] and HqNO, affords the dinuclear heterometallic compounds [Ln(hfac)3Al(qNO)3] (Ln3+ = Eu3+, Gd3+ and Er3+) in high yields. The molecular structures of these new compounds revealed a dinuclear species with three phenolic oxygen atoms bridging the two metal atoms. While the europium and gadolinium complexes show the coordination number (CN) 9 for the lanthanide centre, in the complex featuring the smaller erbium ion, only two oxygens bridge the two metal atoms for a resulting CN of 8. The reaction of [Eu(hfac)3] with [Alq3] (Hq = 8-hydroxyquinoline) in the same conditions yields a heterometallic product of composition [Eu(hfac)3Alq3]. A recrystallization attempt from hot heptane in air produced single crystals of two different morphologies and compositions: [Eu2(hfac)6Al2q4(OH)2] and [Eu2(hfac)6(µ-Hq)2]. The latter compound can be directly prepared from [Eu(hfac)3] and Hq at room temperature. Quantum mechanical calculations confirm (i) the higher stability of [Eu(hfac)3Al(qNO)3] vs. the corresponding [Eu(hfac)3Alq3] and (ii) the preference of the Er complexes for the CN 8, justifying the different behaviour in terms of the Lewis acidity of the metal centre. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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19 pages, 3055 KiB  
Article
Photocatalytic Reduction of CO2 into CO with Cyclometalated Pt(II) Complexes of N^C^N Pincer Dipyridylbenzene Ligands: A DFT Study
by Antonia Sarantou and Athanassios Tsipis
Molecules 2024, 29(2), 403; https://doi.org/10.3390/molecules29020403 - 14 Jan 2024
Viewed by 1156
Abstract
In this work, density functional theory (DFT) calculations were employed to study the photocatalytic reduction of CO2 into CO using a series of Pt(II) square planar complexes with the general formula [Pt(5-R-dpb)Cl] (dpb = 1,3-di(2-pyridyl)benzene anion, R = H, N,N [...] Read more.
In this work, density functional theory (DFT) calculations were employed to study the photocatalytic reduction of CO2 into CO using a series of Pt(II) square planar complexes with the general formula [Pt(5-R-dpb)Cl] (dpb = 1,3-di(2-pyridyl)benzene anion, R = H, N,N-dimethylaniline,T thiophene, diazaborinine). The CO2-into-CO conversion process is thought to proceed via two main steps, namely the photocatalytic/reduction step and the main catalytic step. The simulated absorption spectra exhibit strong bands in the range 280–460 nm of the UV-Vis region. Reductive quenching of the T1 state of the complexes under study is expected to be favorable since the calculated excited state redox potentials for the reaction with sacrificial electron donors are highly positive. The redox potentials reveal that the reductive quenching of the T1 state, important to the overall process, could be modulated by suitable changes in the N^C^N pincer ligands. The CO2 fixation and activation by the three coordinated Pt(II) catalytically active species are predicted to be favorable, with the Pt–CO2 bond dissociation energies D0 in the range of −36.9–−10.3 kcal/mol. The nature of the Pt–CO2 bond of the Pt(II) square planar intermediates is complex, with covalent, hyperconjugative and H-bonding interactions prevailing over the repulsive electrostatic interactions. The main catalytic cycle is estimated to be a favorable exergonic process. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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13 pages, 3248 KiB  
Article
{GdIII7} and {GdIII14} Cluster Formation Based on a Rhodamine 6G Ligand with a Magnetocaloric Effect
by Lin Miao, Cai-Ming Liu and Hui-Zhong Kou
Molecules 2024, 29(2), 389; https://doi.org/10.3390/molecules29020389 - 12 Jan 2024
Cited by 1 | Viewed by 911
Abstract
Heptanuclear {GdIII7} (complex 1) and tetradecanuclear {GdIII14} (complex 2) were synthesized using the rhodamine 6G ligand HL (rhodamine 6G salicylaldehyde hydrazone) and characterized. Complex 1 has a rare disc-shaped structure, where the central Gd ion [...] Read more.
Heptanuclear {GdIII7} (complex 1) and tetradecanuclear {GdIII14} (complex 2) were synthesized using the rhodamine 6G ligand HL (rhodamine 6G salicylaldehyde hydrazone) and characterized. Complex 1 has a rare disc-shaped structure, where the central Gd ion is connected to the six peripheral GdIII ions via CH3O3-OH bridges. Complex 2 has an unexpected three-layer double sandwich structure with a rare μ6-O2− ion in the center of the cluster. Magnetic studies revealed that complex 1 exhibits a magnetic entropy change of 17.4 J kg−1 K−1 at 3 K and 5 T. On the other hand, complex 2 shows a higher magnetic entropy change of 22.3 J kg−1 K−1 at 2 K and 5 T. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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13 pages, 1490 KiB  
Article
Cd2+-Selective Fluorescence Enhancement of Bisquinoline Derivatives with 2-Aminoethanol Skeleton
by Yuji Mikata, Aya Tsuruta, Hinata Koike, Sunao Shoji and Hideo Konno
Molecules 2024, 29(2), 369; https://doi.org/10.3390/molecules29020369 - 11 Jan 2024
Cited by 1 | Viewed by 819
Abstract
The development of fluorescent Cd2+ sensors requires strict selectivity over Zn2+ because of the high availability of Zn2+ in the natural environment. In this paper, bisquinoline-based fluorescent sensors with a 2-aminoethanol backbone were investigated. The weak coordination ability of quinoline [...] Read more.
The development of fluorescent Cd2+ sensors requires strict selectivity over Zn2+ because of the high availability of Zn2+ in the natural environment. In this paper, bisquinoline-based fluorescent sensors with a 2-aminoethanol backbone were investigated. The weak coordination ability of quinoline compared to well-studied pyridine is suitable for Cd2+ selectivity rather than Zn2+. In the presence of 3 equiv. of metal ions, TriMeO-N,O-BQMAE (N,O-bis(5,6,7-trimethoxy-2-quinolylmethyl)-2-methylaminoethanol (3)), as well as its N,N-isomer TriMeO-N,N-BQMAE (N,N-bis(5,6,7-trimethoxy-2-quinolylmethyl)-2-methoxyethylamine (6)), exhibits Cd2+-selective fluorescence enhancement over Zn2+ in DMF-HEPES buffer (1:1, 50 mM HEPES, 0.1 M KCl, pH = 7.5) (IZn/ICd = 26–34%), which has similar selectivity in comparison to the corresponding ethylenediamine derivative TriMeOBQDMEN (N,N’-bis(5,6,7-trimethoxy-2-quinolylmethyl)-N,N’-dimethylethylenediamine) under the same experimental condition (IZn/ICd = 24%). The fluorescence mechanisms of N,O- and N,N-isomers of BQMAE are quite different, judging from the fluorescence lifetimes of their metal complexes. The Cd2+ complex with TriMeO-N,O-BQMAE (3) exhibits a long fluorescence lifetime similar to that of TriMeOBQDMEN via intramolecular excimer emission, whereas the Cd2+ complex with TriMeO-N,N-BQMAE (6) exhibits a short lifetime from monomer emission. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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13 pages, 2415 KiB  
Article
A Pair of Multifunctional Cu(II)–Dy(III) Enantiomers with Zero–Field Single–Molecule Magnet Behaviors, Proton Conduction Properties and Magneto–Optical Faraday Effects
by Shui-Dong Zhu, Yu-Lin Zhou, Fang Liu, Yu Lei, Sui-Jun Liu, He-Rui Wen, Bin Shi, Shi-Yong Zhang, Cai-Ming Liu and Ying-Bing Lu
Molecules 2023, 28(22), 7506; https://doi.org/10.3390/molecules28227506 - 9 Nov 2023
Cited by 2 | Viewed by 1220
Abstract
Multifunctional materials with a coexistence of proton conduction properties, single–molecule magnet (SMM) behaviors and magneto–optical Faraday effects have rarely been reported. Herein, a new pair of Cu(II)–Dy(III) enantiomers, [DyCu2(RR/SS–H2L)2(H2O)4(NO3) [...] Read more.
Multifunctional materials with a coexistence of proton conduction properties, single–molecule magnet (SMM) behaviors and magneto–optical Faraday effects have rarely been reported. Herein, a new pair of Cu(II)–Dy(III) enantiomers, [DyCu2(RR/SS–H2L)2(H2O)4(NO3)2]·(NO3)·(H2O) (R1 and S1) (H4L = [RR/SS] –N,N′–bis [3–hydroxysalicylidene] –1,2–cyclohexanediamine), has been designed and prepared using homochiral Schiff–base ligands. R1 and S1 contain linear Cu(II)–Dy(III)–Cu(II) trinuclear units and possess 1D stacking channels within their supramolecular networks. R1 and S1 display chiral optical activity and strong magneto–optical Faraday effects. Moreover, R1 shows a zero–field SMM behavior. In addition, R1 demonstrates humidity– and temperature–dependent proton conductivity with optimal values of 1.34 × 10−4 S·cm−1 under 50 °C and 98% relative humidity (RH), which is related to a 1D extended H–bonded chain constructed by water molecules, nitrate and phenol groups of the RR–H2L ligand. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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14 pages, 1573 KiB  
Article
Antimicrobial Activity of Manganese(I) Tricarbonyl Complexes Bearing 1,2,3-Triazole Ligands
by Sofia Friães, Cândida Trigueiros, Clara S. B. Gomes, Alexandra R. Fernandes, Oscar A. Lenis-Rojas, Marta Martins and Beatriz Royo
Molecules 2023, 28(21), 7453; https://doi.org/10.3390/molecules28217453 - 6 Nov 2023
Viewed by 1890
Abstract
Background. Antimicrobial resistance is one of the most pressing health issues of our time. The increase in the number of antibiotic-resistant bacteria allied to the lack of new antibiotics has contributed to the current crisis. It has been predicted that if this situation [...] Read more.
Background. Antimicrobial resistance is one of the most pressing health issues of our time. The increase in the number of antibiotic-resistant bacteria allied to the lack of new antibiotics has contributed to the current crisis. It has been predicted that if this situation is not dealt with, we will be facing 10 million deaths due to multidrug resistant infections per year by 2050, surpassing cancer-related deaths. This alarming scenario has refocused attention into researching alternative drugs to treat multidrug-resistant infections. Aims. In this study, the antimicrobial activities of four manganese complexes containing 1,2,3,-triazole and clotrimazole ligands have been evaluated. It is known that azole antibiotics coordinated to manganese tricarbonyl complexes display interesting antimicrobial activities against several microbes. In this work, the effect of the introduction of 1,2,3,-triazole-derived ligands in the [Mn(CO)3(clotrimazole)] fragment has been investigated against one Gram-positive bacterium and five Gram-negative bacteria. Methods. The initial antimicrobial activity of the above-mentioned complexes was assessed by determining the minimum inhibitory and bactericidal concentrations using the broth microdilution method. Growth curves in the presence and absence of the complexes were performed to determine the effects of these complexes on the growth of the selected bacteria. A possible impact on cellular viability was determined by conducting the MTS assay on human monocytes. Results. Three of the Mn complexes investigated (46) had good antimicrobial activities against all the bacteria tested, with values ranging from 1.79 to 61.95 µM with minimal toxicity. Conclusions. Due to the increased problem of antibiotic resistance and a lack of new antibacterial drugs with no toxicity, these results are exciting and show that these types of complexes can be an avenue to pursue in the future. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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15 pages, 2590 KiB  
Article
A Norbornadiene-Based Molecular System for the Storage of Solar–Thermal Energy in an Aqueous Solution: Study of the Heat-Release Process Triggered by a Co(II)-Complex
by Franco Castro, Jorge S. Gancheff, Juan C. Ramos, Gustavo Seoane, Carla Bazzicalupi, Antonio Bianchi, Francesca Ridi and Matteo Savastano
Molecules 2023, 28(21), 7270; https://doi.org/10.3390/molecules28217270 - 25 Oct 2023
Cited by 2 | Viewed by 2088
Abstract
It is urgent yet challenging to develop new environmentally friendly and cost-effective sources of energy. Molecular solar thermal (MOST) systems for energy capture and storage are a promising option. With this in mind, we have prepared a new water-soluble (pH > 6) norbornadiene [...] Read more.
It is urgent yet challenging to develop new environmentally friendly and cost-effective sources of energy. Molecular solar thermal (MOST) systems for energy capture and storage are a promising option. With this in mind, we have prepared a new water-soluble (pH > 6) norbornadiene derivative (HNBD1) whose MOST properties are reported here. HNBD1 shows a better matching to the solar spectrum compared to unmodified norbornadiene, with an onset absorbance of λonset = 364 nm. The corresponding quadricyclane photoisomer (HQC1) is quantitatively generated through the light irradiation of HNBD1. In an alkaline aqueous solution, the MOST system consists of the NBD1/QC1 pair of deprotonated species. QC1 is very stable toward thermal back-conversion to NBD1; it is absolutely stable at 298 K for three months and shows a marked resistance to temperature increase (half-life t½ = 587 h at 371 K). Yet, it rapidly (t½ = 11 min) releases the stored energy in the presence of the Co(II) porphyrin catalyst Co-TPPC (ΔHstorage = 65(2) kJ∙mol−1). Under the explored conditions, Co-TPPC maintains its catalytic activity for at least 200 turnovers. These results are very promising for the creation of MOST systems that work in water, a very interesting solvent for environmental sustainability, and offer a strong incentive to continue research towards this goal. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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26 pages, 9014 KiB  
Article
Effects of Ferrocene and Ferrocenium on MCF-7 Breast Cancer Cells and Interconnection with Regulated Cell Death Pathways
by Cristina Favaron, Elisabetta Gabano, Ilaria Zanellato, Ludovica Gaiaschi, Claudio Casali, Maria Grazia Bottone and Mauro Ravera
Molecules 2023, 28(18), 6469; https://doi.org/10.3390/molecules28186469 - 6 Sep 2023
Cited by 2 | Viewed by 1807
Abstract
The effects of ferrocene (Fc) and ferrocenium (Fc+) induced in triple negative human breast cancer MCF-7 cells were explored by immunofluorescence, flow cytometry, and transmission electron microscopy analysis. The different abilities of Fc and Fc+ to produce [...] Read more.
The effects of ferrocene (Fc) and ferrocenium (Fc+) induced in triple negative human breast cancer MCF-7 cells were explored by immunofluorescence, flow cytometry, and transmission electron microscopy analysis. The different abilities of Fc and Fc+ to produce reactive oxygen species and induce oxidative stress were clearly observed by activating apoptosis and morphological changes after treatment, but also after tests performed on the model organism D. discoideum, particularly in the case of Fc+. The induction of ferroptosis, an iron-dependent form of regulated cell death driven by an overload of lipid peroxides in cellular membranes, occurred after 2 h of treatment with Fc+ but not Fc. However, the more stable Fc showed its effects by activating necroptosis after a longer-lasting treatment. The differences observed in terms of cell death mechanisms and timing may be due to rapid interconversion between the two oxidative forms of internalized iron species (from Fe2+ to Fe3+ and vice versa). Potential limitations include the fact that iron metabolism and mitophagy have not been investigated. However, the ability of both Fc and Fc+ to trigger different and interregulated types of cell death makes them suitable to potentially overcome the shortcomings of traditional apoptosis-mediated anticancer therapies. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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13 pages, 7623 KiB  
Article
The Preparation of a Challenging Superconductor Nb3Al by Exploiting Nano Effect
by Chengkai Luan, Xiyue Cheng, Xiuping Gao, Jürgen Köhler and Shuiquan Deng
Molecules 2023, 28(18), 6455; https://doi.org/10.3390/molecules28186455 - 6 Sep 2023
Viewed by 1193
Abstract
The Nb3Al superconductor with excellent physical and working properties is one of the most promising materials in high-magnetic-field applications. However, it is difficult to prepare high-quality Nb3Al with a desired superconducting transition temperature (Tc) because of [...] Read more.
The Nb3Al superconductor with excellent physical and working properties is one of the most promising materials in high-magnetic-field applications. However, it is difficult to prepare high-quality Nb3Al with a desired superconducting transition temperature (Tc) because of its narrow phase formation area at high temperatures (>1940 °C). This work reports a method to prepare stoichiometric Nb3Al powder samples at a relatively low temperature (1400 °C) by exploiting the nano effect of Nb particles with pretreatment of Nb powder under H2/Ar atmosphere. The obtained Nb3Al samples exhibit high Tc’s of ~16.8K. Based on density functional theory (DFT) calculations and statistical mechanics analysis, the crucial role of quantum effect in leading to the success of the preparation method was studied. A new measure of surface energy (MSE) of a model particle is introduced to study its size and face dependence. A rapid convergence of the MSE with respect to the size indicates a quick approach to the solid limit, while the face dependence of MSE reveals a liquid-like behavior. The surface effect and quantum fluctuation of the Nbn clusters explain the success of the preparation method. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 3362 KiB  
Article
Terbium and Europium Chlorocyananilate-Based 2D Coordination Polymers
by Mariangela Oggianu, Alexandre Abhervé, Daniela Marongiu, Francesco Quochi, José Ramón Galán-Mascarós, Federica Bertolotti, Norberto Masciocchi, Narcis Avarvari and Maria Laura Mercuri
Molecules 2023, 28(18), 6453; https://doi.org/10.3390/molecules28186453 - 6 Sep 2023
Cited by 3 | Viewed by 1135
Abstract
Two-dimensional layered coordination polymers based on the hetero-substituted 3-chloro-6-cyano-2,5-dihydroxybenzoquinone ligands, hereafter ClCNAn2− anilate, and LnIII ions (Tb and Eu) are reported. Compounds 1 and 2, formulated as Ln2(ClCNAn)3(DMSO)6 (LnIII = Tb, 1; Eu, [...] Read more.
Two-dimensional layered coordination polymers based on the hetero-substituted 3-chloro-6-cyano-2,5-dihydroxybenzoquinone ligands, hereafter ClCNAn2− anilate, and LnIII ions (Tb and Eu) are reported. Compounds 1 and 2, formulated as Ln2(ClCNAn)3(DMSO)6 (LnIII = Tb, 1; Eu, 2), and their related intermediates 1′ and 2′, formulated as Ln2(ClCNAn)3(H2O)x·yH2O (x + y likely = 12, Ln = Tb, 1′; and Eu, 2′), were prepared by a conventional one-pot reaction (the latter) and recrystallized from DMSO solvent (the former). Polyhydrated intermediates 1′ and 2′ show very similar XRPD patterns, while, despite their common stoichiometry, 1 and 2 are not isostructural. Compound 1 consists of a 2D coordination framework of 3,6 topology, where [Tb(DMSO)3]III moieties are bridged by three bis-chelating ClCNAn2− ligands, forming distorted hexagons. Ultrathin nanosheets of 1 were obtained by exfoliation via the liquid-assisted sonication method and characterized by atomic force microscopy, confirming the 2D nature of 1. The crystal structure of 2, still showing the presence of 2D sheets with a “hexagonal” mesh and a common (3,6) connectivity, is based onto flat, non-corrugated slabs. Indeed, at a larger scale, the different “rectangular tiles” show clear roofing in 1, which is totally absent in 2. The magnetic behavior of 1 very likely indicates depopulation of the highest crystal-field levels, as expected for TbIII compounds. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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13 pages, 2159 KiB  
Article
The Anti-Breast Cancer Stem Cell Potency of Copper(I)-Non-Steroidal Anti-Inflammatory Drug Complexes
by Alice Johnson, Xiao Feng, Kuldip Singh, Fabrizio Ortu and Kogularamanan Suntharalingam
Molecules 2023, 28(17), 6401; https://doi.org/10.3390/molecules28176401 - 1 Sep 2023
Cited by 3 | Viewed by 1304
Abstract
Cancer stem cells (CSCs) are thought to be partly responsible for metastasis and cancer relapse. Currently, there are no effective therapeutic options that can remove CSCs at clinically safe doses. Here, we report the synthesis, characterisation, and anti-breast CSC properties of a series [...] Read more.
Cancer stem cells (CSCs) are thought to be partly responsible for metastasis and cancer relapse. Currently, there are no effective therapeutic options that can remove CSCs at clinically safe doses. Here, we report the synthesis, characterisation, and anti-breast CSC properties of a series of copper(I) complexes, comprising of non-steroidal anti-inflammatory drugs (NSAIDs) and triphenylphosphine ligands (13). The copper(I) complexes are able to reduce the viability of breast CSCs grown in two- and three-dimensional cultures at micromolar concentrations. The potency of the copper(I) complexes towards breast CSCs was similar to salinomycin (an established anti-breast CSC agent) and cisplatin (a clinically used metallopharmaceutical). Cell-based studies showed that the copper(I) complexes are readily, and similarly, internalised by breast CSCs. The copper(I) complexes significantly increase the intracellular reactive oxygen species (ROS) levels in breast CSCs, and their ROS generation profile with respect to time is dependent on the NSAID component present. The generation of intracellular ROS by the copper(I) complexes could be part of the underlying mechanism by which they evoke breast CSC death. As far as we are aware, this is the first study to explore the anti-breast CSC properties of copper(I) complexes. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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16 pages, 16575 KiB  
Article
Aldiminium Cations as Countercations to Discrete Main Group Fluoroanions
by Evelin Gruden and Gašper Tavčar
Molecules 2023, 28(17), 6270; https://doi.org/10.3390/molecules28176270 - 27 Aug 2023
Viewed by 1026
Abstract
The reactions of group 14 tetrafluorides (SiF4, GeF4, and SnF4) and group 15 pentafluorides (PF5, AsF5, and SbF5) with the CAAC-based trifluoride reagent [MeCAACH][F(HF)2] led to the [...] Read more.
The reactions of group 14 tetrafluorides (SiF4, GeF4, and SnF4) and group 15 pentafluorides (PF5, AsF5, and SbF5) with the CAAC-based trifluoride reagent [MeCAACH][F(HF)2] led to the isolation of salts containing discrete 5- or 6-coordinated fluoroanions. The syntheses of [MeCAACH][SiF5], [MeCAACH][GeF5], [MeCAACH][(THF)SnF5], and the structurally related [MeCAACH][(dioxane)SnF5], [MeCAACH][PF6], [MeCAACH][AsF6], and [MeCAACH][SbF6] are effective, selective and in high yield. All compounds were characterized by X-ray single-crystal structure analysis, NMR and Raman spectroscopy. It is worth noting that the synthesized [MeCAACH][GeF5] is a rare example of a structurally characterized compound with discrete [GeF5] anion, while [MeCAACH][(THF)SnF5] and [MeCAACH][(dioxane)SnF5] represent the first compounds with discrete octahedrally coordinated tin fluoride anions with incorporated solvent molecules. Finally, the aldiminium-based cation [MeCAACH]+ proved to be suitable for the stabilization of rare discrete main group fluoride anions. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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12 pages, 3578 KiB  
Article
Observation of Two-Step Spin Transition in Graphene Oxide-Based Hybrids with Iron(II) 4-amino-1,2,4-triazole Spin Crossover Nanoparticles
by Nikolia Lalioti, Alexander Charitos, John Parthenios, Ondrej Malina, Michaela Polaskova, Martin Petr and Vassilis Tangoulis
Molecules 2023, 28(15), 5816; https://doi.org/10.3390/molecules28155816 - 2 Aug 2023
Cited by 1 | Viewed by 1132
Abstract
A novel experimental protocol based on a reverse micellar method is presented for the synthesis of graphene oxide (GO)-based hybrids with spin crossover nanoparticles (SCO NPs) of the 1D iron(II) coordination polymer with the formula [Fe(NH2trz)3](Br2). By [...] Read more.
A novel experimental protocol based on a reverse micellar method is presented for the synthesis of graphene oxide (GO)-based hybrids with spin crossover nanoparticles (SCO NPs) of the 1D iron(II) coordination polymer with the formula [Fe(NH2trz)3](Br2). By introducing different quantities of 0.5% and 1.0% of GO (according to iron(II)) into the aqueous phase, two hybrids, NP4 and NP5, were synthesized, respectively. The morphological homogeneity of the NPs on the surface of the GO flakes is greatly improved in comparison to the pristine [Fe(NH2trz)3](Br2) NPs. From the magnetic point of view and at a low magnetic sweep rate of 1 K/min, a two-step hysteretic behavior is observed for NP4 and NP5, where the onset of the low-temperature second step appeared at 40% and 30% of the HS fraction, respectively. For faster sweep rates of 5–10 K/min, the two steps from the cooling branch are progressively smeared out, and the critical temperatures observed are T1/2 = 343 K and T1/2 = 288 K, with a thermal width of 55 K for both NP4 and NP5. A Raman laser power-assisted protocol was used to monitor the thermal tolerance of the hybrids, while XPS analysis revealed electronic interactions between the SCO NPs and the GO flakes. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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31 pages, 94288 KiB  
Article
Syntheses, Structures, and Corrosion Inhibition of Various Alkali Metal Carboxylate Complexes
by Vidushi P. Vithana, Zhifang Guo, Glen B. Deacon and Peter C. Junk
Molecules 2023, 28(14), 5515; https://doi.org/10.3390/molecules28145515 - 19 Jul 2023
Viewed by 1653
Abstract
Complexes of the alkali metals Li-Cs with 3-thiophenecarboxylate (3tpc), 2-methyl-3-furoate (2m3fur), 3-furoate (3fur), 4-hydroxycinnamate (4hocin), and 4-hydroxybenzoate (4hob) ions were prepared via neutralisation reactions, and the structures of [Li2(3tpc)2]n (1Li); [K2(3tpc)2]n [...] Read more.
Complexes of the alkali metals Li-Cs with 3-thiophenecarboxylate (3tpc), 2-methyl-3-furoate (2m3fur), 3-furoate (3fur), 4-hydroxycinnamate (4hocin), and 4-hydroxybenzoate (4hob) ions were prepared via neutralisation reactions, and the structures of [Li2(3tpc)2]n (1Li); [K2(3tpc)2]n (1K); [Rb(3tpc)(H2O)]n (1Rb); [Cs{H(3tpc)2}]n (1Cs); [Li2(2m3fur)2(H2O)3] (2Li); [K2(2m3fur)2(H2O)]n (2K); [Li(3fur)]n(3Li); [K(4hocin](H2O)3]n (4K); [Rb{H(4hocin)2}]n.nH2O (4Rb); [Cs(4hocin)(H2O)]n (4Cs); [Li(4hob)]n (5Li); [K(4hob)(H2O)3]n (5K); [Rb(4hob)(H2O)]n (5Rb); and [Cs(4hob)(H2O)]n (5Cs) were determined via X-ray crystallography. Bulk products were also characterised via XPD, IR, and TGA measurements. No sodium derivatives could be obtained as crystallographically suitable single crystals. All were obtained as coordination polymers with a wide variety of carboxylate-binding modes, except for dinuclear 2Li. Under conditions that normally gave coordinated carboxylate ions, the ligation of hydrogen dicarboxylate ions was observed in 1Cs and 4Rb, with short H-bonds and short O…O distances associated with the acidic hydrogen. The alkali-metal carboxylates showed corrosion inhibitor properties inferior to those of the corresponding rare-earth carboxylates. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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17 pages, 15144 KiB  
Article
Ge–Cu-Complexes Ph(pyO)Ge(μ2-pyO)2CuCl and PhGe(μ2-pyO)4CuCl—Representatives of Cu(I)→Ge(IV) and Cu(II)→Ge(IV) Dative Bond Systems
by Jörg Wagler and Robert Gericke
Molecules 2023, 28(14), 5442; https://doi.org/10.3390/molecules28145442 - 16 Jul 2023
Cited by 1 | Viewed by 1244
Abstract
Phenylgermaniumpyridine-2-olate PhGe(pyO)3 (compound 1Ge) and CuCl react with the formation of the heteronuclear complex Ph(pyO)Ge(μ2-pyO)2CuCl (2Ge’) rather than forming the expected compound PhGe(μ2-pyO)3CuCl (2Ge). Single-point calculations (at the B2T-PLYP [...] Read more.
Phenylgermaniumpyridine-2-olate PhGe(pyO)3 (compound 1Ge) and CuCl react with the formation of the heteronuclear complex Ph(pyO)Ge(μ2-pyO)2CuCl (2Ge’) rather than forming the expected compound PhGe(μ2-pyO)3CuCl (2Ge). Single-point calculations (at the B2T-PLYP level) of the optimized molecular structures confirmed the relative stability of isomer 2Ge’ over 2Ge and, for the related silicon congeners, the relative stability of 2Si over 2Si’. Decomposition of a solution of 2Ge’ upon access to air provided access to some crystals of the copper(II) compound PhGe(μ2-pyO)4CuCl (3Ge). Compounds 2Ge’ and 3Ge were characterized by single-crystal X-ray diffraction analyses, and the Ge–Cu bonds in these compounds were analyzed with the aid of quantum chemical calculations, e.g., Natural Bond Orbital analyses (NBO), Non-Covalent Interactions descriptor (NCI), and topology of the electron density at bond critical point using Quantum Theory of Atoms-In-Molecules (QTAIM) in conjunction with the related silicon compounds PhSi(μ2-pyO)3CuCl (2Si), PhSi(μ2-pyO)4CuCl (3Si), as well as the potential isomers Ph(pyO)Si(μ2-pyO)2CuCl (2Si’) and PhGe(μ2-pyO)3CuCl (2Ge). Pronounced Cu→Ge (over Cu→Si) lone pair donation was found for the Cu(I) compounds, whereas in Cu(II) compounds 3Si and 3Ge, this σ-donation is less pronounced and only marginally enhanced in 3Ge over 3Si. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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Review

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38 pages, 19100 KiB  
Review
Polyanion Condensation in Inorganic and Hybrid Fluoridometallates (IV) of Octahedrally Coordinated Ti, Zr, Hf, V, Cr, W, Mn, Ge, Sn, and Pb
by Zoran Mazej
Molecules 2024, 29(6), 1361; https://doi.org/10.3390/molecules29061361 - 19 Mar 2024
Viewed by 864
Abstract
In fluorides, the M4+ cations of M = Ti, V, Cr, Mn, Ge, Sn, and Pb favour the octahedral coordination of six F ligands. Some examples of M4+ with larger cations (M = Zr, Hf, W) in octahedral coordination are also [...] Read more.
In fluorides, the M4+ cations of M = Ti, V, Cr, Mn, Ge, Sn, and Pb favour the octahedral coordination of six F ligands. Some examples of M4+ with larger cations (M = Zr, Hf, W) in octahedral coordination are also known. If not enough F ligands are available to have isolated MIVF6 octahedra, they must share their F ligands. The crystal structures of such fluoride metalates (IV) show the variety of possible structural motifs of the zero-dimensional oligomeric anions [M2F11]3− (M = Ti, Cr), [M3F15]3− (M = Zr, Hf), [M3F16]4− (M = Ge), [M4F18]2− (M = Ti, W), [M4F19]3− (M = Ti), [M4F20]4− (M = Ti), [M5F23]3− (M = Ti), [M6F27]3− (M = Ti), [M6F28]4− (M = Ti), [M8F36]4− (M = Ti, Mn), [M10F45]5− (M = Ti) to one-dimensional chains ([MF5]) (M = V, Ti, Cr, Ge, Sn, Pb), double chains ([M2F9]) (M = Ti, Mn), columns ([M3F13]) (M = Ti), ([M4F19]3−) (M = Ti), ([M7F30]2−) (M = Ti), ([M9F38]2−)) (M = Ti), two-dimensional layers ([M2F9]) (M = Cr), ([M8F33]) (M = Ti), and three-dimensional ([M6F27]3−) (M = Ti) architectures. A discrete monomeric [M2F9] anion with two MIVF6 octahedra sharing a common face has not yet been experimentally demonstrated, while two examples containing discrete dimeric [M2F10]2− anions (M = Ti) with two MIVF6 octahedra sharing an edge are still in question. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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18 pages, 7634 KiB  
Review
Biomedical Applications of Sulfonylcalix[4]arene-Based Metal–Organic Supercontainers
by Ya-Wen Fan, Meng-Xue Shi, Zhenqiang Wang, Feng-Rong Dai and Zhong-Ning Chen
Molecules 2024, 29(6), 1220; https://doi.org/10.3390/molecules29061220 - 8 Mar 2024
Cited by 1 | Viewed by 1226
Abstract
Coordination cages sustained by metal–ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal–organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an [...] Read more.
Coordination cages sustained by metal–ligand interactions feature polyhedral architectures and well-defined hollow structures, which have attracted significant attention in recent years due to a variety of structure-guided promising applications. Sulfonylcalix[4]arenes-based coordination cages, termed metal–organic supercontainers (MOSCs), that possess unique multi-pore architectures containing an endo cavity and multiple exo cavities, are emerging as a new family of coordination cages. The well-defined built-in multiple binding domains of MOSCs allow the efficient encapsulation of guest molecules, especially for drug delivery. Here, we critically discuss the design strategy, and, most importantly, the recent advances in research surrounding cavity-specified host–guest chemistry and biomedical applications of MOSCs. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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18 pages, 8970 KiB  
Review
Recent Progress on Perovskite-Based Electrocatalysts for Efficient CO2 Reduction
by Tong Wu, Lihua Zhang, Yinbo Zhan, Yilin Dong, Zheng Tan, Bowei Zhou, Fei Wei, Dongliang Zhang and Xia Long
Molecules 2023, 28(24), 8154; https://doi.org/10.3390/molecules28248154 - 18 Dec 2023
Cited by 1 | Viewed by 1779
Abstract
An efficient carbon dioxide reduction reaction (CO2RR), which reduces CO2 to low-carbon fuels and high-value chemicals, is a promising approach for realizing the goal of carbon neutrality, for which effective but low-cost catalysts are critically important. Recently, many inorganic perovskite-based [...] Read more.
An efficient carbon dioxide reduction reaction (CO2RR), which reduces CO2 to low-carbon fuels and high-value chemicals, is a promising approach for realizing the goal of carbon neutrality, for which effective but low-cost catalysts are critically important. Recently, many inorganic perovskite-based materials with tunable chemical compositions have been applied in the electrochemical CO2RR, which exhibited advanced catalytic performance. Therefore, a timely review of this progress, which has not been reported to date, is imperative. Herein, the physicochemical characteristics, fabrication methods and applications of inorganic perovskites and their derivatives in electrochemical CO2RR are systematically reviewed, with emphasis on the structural evolution and product selectivity of these electrocatalysts. What is more, the current challenges and future directions of perovskite-based materials regarding efficient CO2RR are proposed, to shed light on the further development of this prospective research area. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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16 pages, 4824 KiB  
Review
Chiral Metal Halide Perovskites: Focus on Lead-Free Materials and Structure-Property Correlations
by Clarissa Coccia, Marco Moroni and Lorenzo Malavasi
Molecules 2023, 28(16), 6166; https://doi.org/10.3390/molecules28166166 - 21 Aug 2023
Cited by 4 | Viewed by 2518
Abstract
Hybrid organic–inorganic perovskites (HOIPs) are promising materials in several fields related to electronics, offering long carrier-diffusion lengths, high absorption coefficients, tunable band gaps, and long spin lifetimes. Recently, chiral perovskites have attracted huge interest thanks to the possibility of further widening the applications [...] Read more.
Hybrid organic–inorganic perovskites (HOIPs) are promising materials in several fields related to electronics, offering long carrier-diffusion lengths, high absorption coefficients, tunable band gaps, and long spin lifetimes. Recently, chiral perovskites have attracted huge interest thanks to the possibility of further widening the applications of HOIPs. Chiral materials, being intrinsically non-centrosymmetric, display several attractive physicochemical properties, including circular dichroism, circularly polarized photoluminescence, nonlinear optics, ferroelectricity, and spin-related effects. Recent studies have shown that chirality can be transferred from the chiral organic ligands into the inorganic perovskite framework, resulting in materials combining the advantages of both chirality and perovskite superior optoelectronic characteristics. As for HOIPs for photovoltaics, strong interest is currently devoted towards the development of lead-free chiral perovskites to overcome any toxicity issue. While considering the basic and general features of chiral HOIPs, this review mainly focuses on lead-free materials. It highlights the first attempts to understand the correlation between the crystal structure characteristics and the chirality-induced functional properties in lead and lead-free chiral perovskites. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry, 2nd Edition)
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