Molecules

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2 pages, 164 KiB

Open AccessEditorial

Lanthanide Complexes in Recent Molecules

by Takashiro Akitsu

Molecules 2022, 27(18), 6019; https://doi.org/10.3390/molecules27186019 - 15 Sep 2022

Viewed by 1029

Abstract

The MDPI journal Molecules publishes excellent papers on molecules in every issue, but I found that there are surprisingly only a few papers (3) and reviews (1) on rare-earth elements (lanthanide) in the category of inorganic chemistry these days [...] Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

Research

Jump to: Editorial, Review

18 pages, 2635 KiB

Open AccessArticle

pH-Sensitive Gold Nanorods for Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) Delivery and DNA-Binding Studies

by Eleni Zygouri, Vlasoula Bekiari, Georgios Malis, Nikos K. Karamanos, Christos Koutsakis, George Psomas and Vassilis Tangoulis

Molecules 2023, 28(9), 3780; https://doi.org/10.3390/molecules28093780 - 27 Apr 2023

Cited by 2 | Viewed by 1479

Abstract

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA [...] Read more.

A facile experimental protocol for the synthesis of poly(ethylene glycol)-modified (PEGylated) gold nanorods (AuNRs@PEG) is presented as well as an effective drug loading procedure using the non-steroidal anti-inflammatory drug (NSAID) naproxen (NAP). The interaction of AuNRs@PEG and drug-loaded AuNRs (AuNRs@PEG@NAP) with calf-thymus DNA was studied at a diverse temperature revealing different interaction modes; AuNRs@PEG may interact via groove-binding and AuNRs@PEG@NAP may intercalate to DNA-bases. The cleavage activity of the gold nanoparticles for supercoiled circular pBR322 plasmid DNA was studied by gel electrophoresis while their affinity for human and bovine serum albumins was also evaluated. Drug-release studies revealed a pH-sensitive behavior with a release up to a maximum of 24% and 33% NAP within the first 180 min at pH = 4.2 and 6.8, respectively. The cytotoxicity of AuNRs@PEG and AuNRs@PEG@NAP was evaluated against MCF-7 and MDA-MB-231 breast cancer cell lines. The development of AuNRs as an efficient non-steroidal anti-inflammatory drugs (NSAIDs) delivery system for chemotherapy is still in its infancy. The present work can shed light and inspire other research groups to work in this direction. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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16 pages, 3481 KiB

Open AccessArticle

Ethoxy Groups on ZrO₂, CuO, CuO/ZrO₂ Al₂O₃, Ga₂O₃, SiO₂ and NiO: Formation and Reactivity

by Jerzy Podobiński, Małgorzata Zimowska, Katarzyna Samson, Michał Śliwa and Jerzy Datka

Molecules 2023, 28(8), 3463; https://doi.org/10.3390/molecules28083463 - 14 Apr 2023

Cited by 2 | Viewed by 1182

Abstract

The reaction of ethanol with surface OH groups on ZrO₂, CuO/ZrO₂, CuO, Al₂O₃, Ga₂O₃, NiO, and SiO₂ was studied by IR spectroscopy. The basicity of oxides was followed by CO [...] Read more.

The reaction of ethanol with surface OH groups on ZrO₂, CuO/ZrO₂, CuO, Al₂O₃, Ga₂O₃, NiO, and SiO₂ was studied by IR spectroscopy. The basicity of oxides was followed by CO₂ adsorption, and their ability to oxidize was investigated by H₂-TPR. It has been found that ethanol reacts with surface OH groups forming ethoxy groups and water. Some oxides: ZrO₂, CuO/ZrO₂, Al₂O₃, and Ga₂O₃ contain several kinds of OH groups (terminal, bidentate, and tridentate) and terminal hydroxyls react with ethanol in the first order. Two kinds of ethoxyls are formed on these oxides: monodental and bidental ones. On the other hand, only one kind of ethoxy group is formed on CuO and NiO. The amount of ethoxy groups correlates with the basicity of oxides. The biggest amount of ethoxyls is produced on the most basic: ZrO₂, CuO/ZrO₂, and Al₂O₃, whereas the smallest amount of ethoxyls is produced on CuO, NiO, and Ga₂O₃, i.e., on oxides of lower basicity. SiO₂ does not form ethoxy groups. Above 370 K ethoxy groups on CuO/ZrO₂, CuO, and NiO are oxidized to acetate ions. The ability of oxides to oxidize ethoxyl groups increases in the order NiO < CuO < CuO/ZrO₂. The temperature of the peak in the H₂-TPR diagram decreases in the same order. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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15 pages, 2708 KiB

Open AccessArticle

Structure, Optical and Magnetic Properties of Two Isomeric 2-Bromomethylpyridine Cu(II) Complexes [Cu(C₆H₉NBr)₂(NO₃)₂] with Very Different Binding Motives

by Fatma Garci, Hammouda Chebbi, Nahal Rouzbeh, Leonhard Rochels, Sabrina Disch, Alexander Haseloer, Sean S. Sebastian, Uwe Ruschewitz, Eric Tobechukwu Anthony, Axel Klein and Mohamed Faouzi Zid

Molecules 2023, 28(2), 731; https://doi.org/10.3390/molecules28020731 - 11 Jan 2023

Viewed by 1392

Abstract

Two isomeric 2-bromomethylpyridine Cu(II) complexes [Cu(C₆H₉NBr)₂(NO₃)₂] with 2-bromo-5-methylpyridine (L¹) and 2-bromo-4-methylpyridine (L²) were synthesized as air-stable blue materials in good yields. The crystal structures were different with [Cu(L¹ [...] Read more.

Two isomeric 2-bromomethylpyridine Cu(II) complexes [Cu(C₆H₉NBr)₂(NO₃)₂] with 2-bromo-5-methylpyridine (L¹) and 2-bromo-4-methylpyridine (L²) were synthesized as air-stable blue materials in good yields. The crystal structures were different with [Cu(L¹)₂(NO₃)₂] (CuL¹) crystallizing in the monoclinic space group P2₁/c, while the 4-methyl derivative CuL² was solved and refined in triclinic P

\bar{1}

. The orientation of the Br substituents in the molecular structure (anti (CuL¹) vs. syn (CuL²) conformations) and the geometry around Cu(II) in an overall 4 + 2 distorted coordination was very different with two secondary (axially elongated) Cu–O bonds on each side of the CuN₂O₂ basal plane in CuL¹ or both on one side in CuL². The two Br substituents in CuL² come quite close to the Cu(II) centers and to each other (Br⋯Br ~3.7 Å). Regardless of these differences, the thermal behavior (TG/DTA) of both materials is very similar with decomposition starting at around 160 °C and CuO as the final product. In contrast to this, FT-IR and Raman frequencies are markedly different for the two isomers and the UV–vis absorption spectra in solution show marked differences in the π–π* absorptions at 263 (CuL²) or 270 (CuL¹) nm and in the ligand-to-metal charge transfer bands at around 320 nm which are pronounced for CuL¹ with the higher symmetry at the Cu(II) center, but very weak for CuL². The T-dependent susceptibility measurements also show very similar results (µ_eff = 1.98 µ_B for CuL¹ and 2.00 µ_B for CuL² and very small Curie–Weiss constants of about −1. The EPR spectra of both complexes show axial symmetry, very similar averaged g values of 2.123 and 2.125, respectively, and no hyper-fine splitting. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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16 pages, 4620 KiB

Open AccessArticle

Expanded Ligands Based upon Iron(II) Coordination Compounds of Asymmetrical Bis(terpyridine) Domains

by Dalila Rocco, Alessandro Prescimone, Catherine E. Housecroft and Edwin C. Constable

Molecules 2023, 28(1), 82; https://doi.org/10.3390/molecules28010082 - 22 Dec 2022

Cited by 1 | Viewed by 1289

Abstract

The synthesis and characterization of two tritopic ligands containing a 2,2′:6′,2″-terpyridine (tpy) metal binding domain and either a 3,2′:6′,3″- or a 4,2′:6′,4″-tpy domain are detailed. The synthetic routes to these ligands involved the [Pd(dppf)Cl₂]-catalyzed coupling of a boronic ester-functionalized 2,2′:6′,2″-tpy with [...] Read more.

The synthesis and characterization of two tritopic ligands containing a 2,2′:6′,2″-terpyridine (tpy) metal binding domain and either a 3,2′:6′,3″- or a 4,2′:6′,4″-tpy domain are detailed. The synthetic routes to these ligands involved the [Pd(dppf)Cl₂]-catalyzed coupling of a boronic ester-functionalized 2,2′:6′,2″-tpy with bromo-derivatives of 3,2′:6′,3″-tpy or 4,2′:6′,4″-tpy. The 2,2′:6′,2″-tpy domains of the tritopic ligands preferentially bind Fe²⁺ in reactions with iron(II) salts leading to the formation of two homoleptic iron(II) complexes containing two peripheral 3,2′:6′,3″-tpy or 4,2′:6′,4″-tpy metal-binding sites, respectively. These iron(II) complexes are potentially tetratopic ligands and represent expanded versions of tetra(pyridin-4-yl)pyrazine. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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9 pages, 2306 KiB

Open AccessArticle

Amorphous Co-Mo-B Film: A High-Active Electrocatalyst for Hydrogen Generation in Alkaline Seawater

by Xiaodong Fang, Xiangguo Wang, Ling Ouyang, Longcheng Zhang, Shengjun Sun, Yimei Liang, Yongsong Luo, Dongdong Zheng, Tairan Kang, Qian Liu, Feng Huo and Xuping Sun

Molecules 2022, 27(21), 7617; https://doi.org/10.3390/molecules27217617 - 06 Nov 2022

Cited by 82 | Viewed by 2263

Abstract

The development of efficient electrochemical seawater splitting catalysts for large-scale hydrogen production is of great importance. In this work, we report an amorphous Co-Mo-B film on Ni foam (Co-Mo-B/NF) via a facile one-step electrodeposition process. Such amorphous Co-Mo-B/NF possesses superior activity with a [...] Read more.

The development of efficient electrochemical seawater splitting catalysts for large-scale hydrogen production is of great importance. In this work, we report an amorphous Co-Mo-B film on Ni foam (Co-Mo-B/NF) via a facile one-step electrodeposition process. Such amorphous Co-Mo-B/NF possesses superior activity with a small overpotential of 199 mV at 100 mA cm⁻² for a hydrogen evolution reaction in alkaline seawater. Notably, Co-Mo-B/NF also maintains excellent stability for at least 24 h under alkaline seawater electrolysis. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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20 pages, 4708 KiB

Open AccessArticle

Non-Antibiotic Antimony-Based Antimicrobials

by Nikolay Gerasimchuk, Kevin Pinks, Tarosha Salpadoru, Kaitlyn Cotton, Olga Michka, Marianna A. Patrauchan and Karen L. Wozniak

Molecules 2022, 27(21), 7171; https://doi.org/10.3390/molecules27217171 - 23 Oct 2022

Cited by 3 | Viewed by 1771

Abstract

A series of the eight novel organoantimony(V) cyanoximates of Sb(C₆H₅)₄L composition was synthesized using the high-yield heterogeneous metathesis reaction between solid AgL (or TlL) and Sb(C₆H₅)₄Br in CH₃CN at [...] Read more.

A series of the eight novel organoantimony(V) cyanoximates of Sb(C₆H₅)₄L composition was synthesized using the high-yield heterogeneous metathesis reaction between solid AgL (or TlL) and Sb(C₆H₅)₄Br in CH₃CN at room temperature. Cyanoximes L were specially selected from a large group of 48 known compounds of this subclass of oximes on the basis of their water solubility and history of prior biological activity. The synthesized compounds are well soluble in organic solvents and were studied using a variety of conventional spectroscopic and physical methods. The crystal structures of all reported organometallic compounds were determined and revealed the formation of the distorted trigonal bipyramidal environment of the Sb atom and monodentate axial binding of acido-ligands via the O atom of the oxime group. The compounds are thermally stable in the solid state and in solution molecular compounds. For the first time, this specially designed series of organoantimony(V) compounds is investigated as potential non-antibiotic antimicrobial agents against three bacterial and two fungal human pathogens known for their increasing antimicrobial resistance. Bacterial pathogens included Gram-negative Escherichia coli and Pseudomonas aeruginosa, and Gram-positive Staphylococcus aureus. Fungal pathogens included Cryptococcus neoformans and Candida albicans. The cyanoximates alone showed no antimicrobial impact, and the incorporation of the SbPh₄ group enabled the antimicrobial effect. Overall, the new antimony compounds showed a strong potential as both broad- and narrow-spectrum antimicrobials against selected bacterial and fundal pathogens and provide insights for further synthetic modifications of the compounds to increase their activities. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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18 pages, 2545 KiB

Open AccessArticle

Assessing the Functional and Structural Stability of the Met80Ala Mutant of Cytochrome c in Dimethylsulfoxide

by Giulia Di Rocco, Antonio Ranieri, Marco Borsari, Marco Sola, Carlo Augusto Bortolotti and Gianantonio Battistuzzi

Molecules 2022, 27(17), 5630; https://doi.org/10.3390/molecules27175630 - 31 Aug 2022

Cited by 1 | Viewed by 1299

Abstract

The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in [...] Read more.

The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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12 pages, 3115 KiB

Open AccessArticle

A Tail Does Not Always Make a Difference: Assembly of cds Nets from Co(NCS)₂ and 1,4-bis(n-Alkyloxy)-2,5-bis(3,2′:6′,3″-terpyridin-4′-yl)benzene Ligands

by Simona S. Capomolla, Giacomo Manfroni, Alessandro Prescimone, Edwin C. Constable and Catherine E. Housecroft

Molecules 2022, 27(15), 4995; https://doi.org/10.3390/molecules27154995 - 05 Aug 2022

Cited by 3 | Viewed by 1444

Abstract

The consistent assembly of a (6⁵.8) cds net is observed in reactions of cobalt(II) thiocyanate with 1,4-bis(n-alkyloxy)-2,5-bis(3,2′:6′,3″-terpyridin-4′-yl)benzene ligands in which the n-alkyloxy substituents are n-propyl (ligand 3), n-butyl (4), n-pentyl (5 [...] Read more.

The consistent assembly of a (6⁵.8) cds net is observed in reactions of cobalt(II) thiocyanate with 1,4-bis(n-alkyloxy)-2,5-bis(3,2′:6′,3″-terpyridin-4′-yl)benzene ligands in which the n-alkyloxy substituents are n-propyl (ligand 3), n-butyl (4), n-pentyl (5), n-hexyl (6), n-heptyl (7), and n-octyl (8). Crystals were grown by layering a methanol solution of Co(NCS)₂ over a 1,2-dichlorobenzene solution of each ligand. The choice of crystallization solvents is critical in directing the assembly of the cds net. Single-crystal structures of [Co(NCS)₂(3)]_n^.3.5nC₆H₄Cl₂, [Co(NCS)₂(4)]_n^.5.5nC₆H₄Cl₂, [Co(NCS)₂(5)]_n^.4nC₆H₄Cl₂, [Co(NCS)₂(6)]_n^.3.8nC₆H₄Cl₂, [Co(NCS)₂(7)]_n^.3.1nC₆H₄Cl₂, and [Co(NCS)₂(8)]_n^.1.6nC₆H₄Cl₂^.2nMeOH (C₆H₄Cl₂ = 1,2-dichlorobenzene) are presented and compared. The n-alkyloxy chains exhibit close to extended conformations and are accommodated in cavities in the lattice without perturbation of the coordination framework. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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12 pages, 3937 KiB

Open AccessArticle

Ethoxy Groups on ZrO₂, CuO, and CuO/ZrO₂ Studied by IR Spectroscopy

by Jerzy Podobiński, Michał Śliwa and Jerzy Datka

Molecules 2022, 27(15), 4790; https://doi.org/10.3390/molecules27154790 - 26 Jul 2022

Cited by 2 | Viewed by 1513

Abstract

The formation, properties, decomposition and reactions of ethoxy groups on ZrO₂, CuO, and CuO/ZrO₂ were followed by IR spectroscopy. The reaction of ethanol with terminal Zr-OH groups leads to the formation of monodendate ethoxy groups (type I), whereas the reaction [...] Read more.

The formation, properties, decomposition and reactions of ethoxy groups on ZrO₂, CuO, and CuO/ZrO₂ were followed by IR spectroscopy. The reaction of ethanol with terminal Zr-OH groups leads to the formation of monodendate ethoxy groups (type I), whereas the reaction of ethanol with tribridged Zr-OH grups results in the formation of bidendate ethoxyls (type II). In both cases, water is produced. Ethoxy groups of type II were also formed on CuO. The type of the surface species detected after interaction of ethanol with CuO/ZrO₂ was the same as detected for both oxides (i.e., ZrO₂ and CuO) separately. This suggests that no new phase was formed in the mixed oxide system. At higher temperatures, ethoxy groups were oxidized forming acetate ions. Gaseous ethanol present in the cell was oxidized to acetaldehyde without the intermediacy of ethoxy groups. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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22 pages, 5227 KiB

Open AccessEditor’s ChoiceArticle

Supramolecular cis-“Bis(Chelation)” of [M(CN)₆]³⁻ (M = Cr^III, Fe^III, Co^III) by Phloroglucinol (H₃PG)

by Katarzyna Jędrzejowska, Jedrzej Kobylarczyk, Dorota Glosz, Emilia Kuzniak-Glanowska, Dominika Tabor, Monika Srebro-Hooper, Jakub J. Zakrzewski, Katarzyna Dziedzic-Kocurek, Tadeusz M. Muzioł and Robert Podgajny

Molecules 2022, 27(13), 4111; https://doi.org/10.3390/molecules27134111 - 26 Jun 2022

Cited by 1 | Viewed by 4189

Abstract

Studies on molecular co-crystal type materials are important in the design and preparation of easy-to-absorb drugs, non-centrosymmetric, and chiral crystals for optical performance, liquid crystals, or plastic phases. From a fundamental point of view, such studies also provide useful information on various supramolecular [...] Read more.

Studies on molecular co-crystal type materials are important in the design and preparation of easy-to-absorb drugs, non-centrosymmetric, and chiral crystals for optical performance, liquid crystals, or plastic phases. From a fundamental point of view, such studies also provide useful information on various supramolecular synthons and molecular ordering, including metric parameters, molecular matching, energetical hierarchy, and combinatorial potential, appealing to the rational design of functional materials through structure–properties–application schemes. Co-crystal salts involving anionic d-metallate coordination complexes are moderately explored (compared to the generality of co-crystals), and in this context, we present a new series of isomorphous co-crystalline salts (PPh₄)₃[M(CN)₆](H₃PG)₂·2MeCN (M = Cr, 1; Fe, 2; Co 3; H₃PG = phloroglucinol, 1,3,5-trihydroxobenzene). In this study, 1–3 were characterized experimentally using SC XRD, Hirshfeld analysis, ESI-MS spectrometry, vibrational IR and Raman, ⁵⁷Fe Mössbauer, electronic absorption UV-Vis-NIR, and photoluminescence spectroscopies, and theoretically with density functional theory calculations. The two-dimensional square grid-like hydrogen-bond {[M(CN)₆]³⁻;(H₃PG)₂}_∞ network features original {[M(CN)₆]³⁻;(H₃PG)₄} supramolecular cis-bis(chelate) motifs involving: (i) two double cyclic hydrogen bond synthons M(-CN⋅⋅⋅HO-)₂Ar, {[M(CN)₆]³⁻;H₂PGH}, between cis-oriented cyanido ligands of [M(CN)₆]³⁻ and resorcinol-like face of H₃PG, and (ii) two single hydrogen bonds M-CN⋅⋅⋅HO-Ar, {[M(CN)₆]³⁻;HPGH₂}, involving the remaining two cyanide ligands. The occurrence of the above tectonic motif is discussed with regard to the relevant data existing in the CCDC database, including the multisite H-bond binding of [M(CN)₆]³⁻ by organic species, mononuclear coordination complexes, and polynuclear complexes. The physicochemical and computational characterization discloses notable spectral modifications under the regime of an extended hydrogen bond network. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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8 pages, 1687 KiB

Open AccessCommunication

An Osteosarcoma Stem Cell Potent Nickel(II)-Polypyridyl Complex Containing Flufenamic Acid

by Ginevra Passeri, Joshua Northcote-Smith, Roshane Perera, Nikola Gubic and Kogularamanan Suntharalingam

Molecules 2022, 27(10), 3277; https://doi.org/10.3390/molecules27103277 - 19 May 2022

Cited by 2 | Viewed by 2190

Abstract

Apoptosis resistance is inherent to stem cell-like populations within tumours and is one of the major reasons for chemotherapy failures in the clinic. Necroptosis is a non-apoptotic mode of programmed cell death that could help bypass apoptosis resistance. Here we report the synthesis, [...] Read more.

Apoptosis resistance is inherent to stem cell-like populations within tumours and is one of the major reasons for chemotherapy failures in the clinic. Necroptosis is a non-apoptotic mode of programmed cell death that could help bypass apoptosis resistance. Here we report the synthesis, characterisation, biophysical properties, and anti-osteosarcoma stem cell (OSC) properties of a new nickel(II) complex bearing 3,4,7,8-tetramethyl-1,10-phenanthroline and two flufenamic acid moieties, 1. The nickel(II) complex 1 is stable in both DMSO and cell media. The nickel(II) complex 1 kills bulk osteosarcoma cells and OSCs grown in monolayer cultures and osteospheres grown in three-dimensional cultures within the micromolar range. Remarkably, 1 exhibits higher potency towards osteospheres than the metal-based drugs used in current osteosarcoma treatment regimens, cisplatin and carboplatin, and an established anti-cancer stem cell agent, salinomycin (up to 7.7-fold). Cytotoxicity studies in the presence of prostaglandin E2 suggest that 1 kills OSCs in a cyclooxygenase-2 (COX-2) dependent manner. Furthermore, the potency of 1 towards OSCs decreased significantly upon co-treatment with necrostatin-1 or dabrafenib, well-known necroptosis inhibitors, implying that 1 induces necroptosis in OSCs. To the best of our knowledge, 1 is the first compound to implicate both COX-2 and necroptosis in its mechanism of action in OSCs. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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13 pages, 1780 KiB

Open AccessArticle

Ligation Motifs in Zinc-Bound Sulfonamide Drugs Assayed by IR Ion Spectroscopy

by Davide Corinti, Barbara Chiavarino, Philippe Maitre, Maria Elisa Crestoni and Simonetta Fornarini

Molecules 2022, 27(10), 3144; https://doi.org/10.3390/molecules27103144 - 14 May 2022

Viewed by 1645

Abstract

The sulfonamide–zinc ion interaction, performing a key role in various biological contexts, is the focus of the present study, with the aim of elucidating ligation motifs in zinc complexes of sulfa drugs, namely sulfadiazine (SDZ) and sulfathiazole (STZ), in a perturbation-free environment. To [...] Read more.

The sulfonamide–zinc ion interaction, performing a key role in various biological contexts, is the focus of the present study, with the aim of elucidating ligation motifs in zinc complexes of sulfa drugs, namely sulfadiazine (SDZ) and sulfathiazole (STZ), in a perturbation-free environment. To this end, an approach is exploited based on mass spectrometry coupled with infrared multiple photon dissociation (IRMPD) spectroscopy backed by quantum chemical calculations. IR spectra of Zn(H₂O+SDZ−H)⁺ and Zn(H₂O+STZ−H)⁺ ions are consistent with a three-coordinate zinc complex, where ZnOH⁺ binds to the uncharged sulfonamide via N(heterocycle) and O(sulfonyl) donor atoms. Alternative prototropic isomers Zn(OH₂)(SDZ−H)⁺ and Zn(OH₂)(STZ−H)⁺ lie 63 and 26 kJ mol⁻¹ higher in free energy, respectively, relative to the ground state Zn(OH)(SDZ)⁺ and Zn(OH)(STZ)⁺ species and do not contribute to any significant extent in the sampled population. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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12 pages, 2981 KiB

Open AccessArticle

Ionic Liquid-Based Polyoxometalate Incorporated at ZIF-8: A Sustainable Catalyst to Combine Desulfurization and Denitrogenation Processes

by Dinis F. Silva, Alexandre M. Viana, Isabel Santos-Vieira, Salete S. Balula and Luís Cunha-Silva

Molecules 2022, 27(5), 1711; https://doi.org/10.3390/molecules27051711 - 05 Mar 2022

Cited by 10 | Viewed by 2080

Abstract

An effective and sustainable process capable of simultaneously execute desulfurization and denitrogenation of fuels is in fact an actual necessity in the refinery industry. The key to achieve this goal is the parallel oxidation of sulfur and nitrogen compounds present in fuels, which [...] Read more.

An effective and sustainable process capable of simultaneously execute desulfurization and denitrogenation of fuels is in fact an actual necessity in the refinery industry. The key to achieve this goal is the parallel oxidation of sulfur and nitrogen compounds present in fuels, which is only achieved by an active and recovered catalyst. A novel heterogeneous catalyst was successfully prepared by the encapsulation of an imidazolium-based polyoxometalate (POM) into a ZIF-8 framework ([BMIM]PMo₁₂@ZIF-8). This composite material revealed exceptional catalytic efficiency to concurrently proceed with the oxidative desulfurization and denitrogenation of a multicomponent model fuel containing various sulfur and nitrogen compounds. A complete removal of all these compounds was achieved after only one hour and the catalyst system was able to be reused for ten consecutive cycles without loss of efficiency. In fact, an ionic liquid POM was incorporated in the ZIF-8 for the first time, and this composite compound was originally applied as a catalyst for simultaneous oxidative desulfurization and denitrogenation processes. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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17 pages, 1710 KiB

Open AccessArticle

Two-Photon Absorption Cooperative Effects within Multi-Dipolar Ruthenium Complexes: The Decisive Influence of Charge Transfers

by Nicolas Durand, Anissa Amar, Rana Mhanna, Huriye Akdas-Kiliç, Olivier Soppera, Jean-Pierre Malval, Abdou Boucekkine and Jean-Luc Fillaut

Molecules 2022, 27(5), 1493; https://doi.org/10.3390/molecules27051493 - 23 Feb 2022

Viewed by 1710

Abstract

One- and two-photon characterizations of a series of hetero- and homoleptic [RuL_3-n(bpy)_n]²⁺ (n = 0, 1, 2) complexes carrying bipyridine π-extended ligands (L), have been carried out. These π-extended D−π−A−A−π−D-type ligands (L), where the electron donor units [...] Read more.

One- and two-photon characterizations of a series of hetero- and homoleptic [RuL_3-n(bpy)_n]²⁺ (n = 0, 1, 2) complexes carrying bipyridine π-extended ligands (L), have been carried out. These π-extended D−π−A−A−π−D-type ligands (L), where the electron donor units (D) are based on diphenylamine, carbazolyl, or fluorenyl units, have been designed to modulate the conjugation extension and the donating effect. Density functional theory calculations were performed in order to rationalize the observed spectra. Calculations show that the electronic structure of the π-extended ligands has a pronounced effect on the composition of HOMO and LUMO and on the metallic contribution to frontier MOs, resulting in strikingly different nonlinear properties. This work demonstrates that ILCT transitions are the keystone of one- and two-photon absorption bands in the studied systems and reveals how much MLCT and LLCT charge transfers play a decisive role on the two-photon properties of both hetero- and homoleptic ruthenium complexes through cooperative or suppressive effects. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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Review

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38 pages, 12689 KiB

Open AccessReview

MRI Contrast Agents in Glycobiology

by Carlos F. G. C. Geraldes and Joop A. Peters

Molecules 2022, 27(23), 8297; https://doi.org/10.3390/molecules27238297 - 28 Nov 2022

Cited by 7 | Viewed by 2091

Abstract

Molecular recognition involving glycoprotein-mediated interactions is ubiquitous in both normal and pathological natural processes. Therefore, visualization of these interactions and the extent of expression of the sugars is a challenge in medical diagnosis, monitoring of therapy, and drug design. Here, we review the [...] Read more.

Molecular recognition involving glycoprotein-mediated interactions is ubiquitous in both normal and pathological natural processes. Therefore, visualization of these interactions and the extent of expression of the sugars is a challenge in medical diagnosis, monitoring of therapy, and drug design. Here, we review the literature on the development and validation of probes for magnetic resonance imaging using carbohydrates either as targeting vectors or as a target. Lectins are important targeting vectors for carbohydrate end groups, whereas selectins, the asialoglycoprotein receptor, sialic acid end groups, hyaluronic acid, and glycated serum and hemoglobin are interesting carbohydrate targets. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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19 pages, 2083 KiB

Open AccessEditor’s ChoiceReview

Rhenium Radioisotopes for Medicine, a Focus on Production and Applications

by Licia Uccelli, Petra Martini, Luca Urso, Teresa Ghirardi, Lorenza Marvelli, Corrado Cittanti, Aldo Carnevale, Melchiore Giganti, Mirco Bartolomei and Alessandra Boschi

Molecules 2022, 27(16), 5283; https://doi.org/10.3390/molecules27165283 - 18 Aug 2022

Cited by 8 | Viewed by 2835

Abstract

In recent decades, the use of alpha; pure beta; or beta/gamma emitters in oncology, endocrinology, and interventional cardiology rheumatology, has proved to be an important alternative to the most common therapeutic regimens. Among radionuclides used for therapy in nuclear medicine, two rhenium radioisotopes [...] Read more.

In recent decades, the use of alpha; pure beta; or beta/gamma emitters in oncology, endocrinology, and interventional cardiology rheumatology, has proved to be an important alternative to the most common therapeutic regimens. Among radionuclides used for therapy in nuclear medicine, two rhenium radioisotopes are of particular relevance: rhenium-186 and rhenium-188. The first is routinely produced in nuclear reactors by direct neutron activation of rhenium-186 via ¹⁸⁵Re(n,γ)¹⁸⁶Re nuclear reaction. Rhenium-188 is produced by the decay of the parent tungsten-188. Separation of rhenium-188 is mainly performed using a chromatographic ¹⁸⁸W/¹⁸⁸Re generator in which tungsten-188 is adsorbed on the alumina column, similar to the ⁹⁹Mo/^99mTc generator system, and the radionuclide eluted in saline solution. The application of rhenium-186 and rhenium-188 depends on their specific activity. Rhenium-186 is produced in low specific activity and is mainly used for labeling particles or diphosphonates for bone pain palliation. Whereas, rhenium-188 of high specific activity can be used for labeling peptides or bioactive molecules. One of the advantages of rhenium is its chemical similarity with technetium. So, diagnostic technetium analogs labeled with radiorhenium can be developed for therapeutic applications. Clinical trials promoting the use of ^186/188Re-radiopharmaceuticals is, in particular, are discussed. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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38 pages, 4530 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Microwave-Assisted Synthesis: Can Transition Metal Complexes Take Advantage of This “Green” Method?

by Elisabetta Gabano and Mauro Ravera

Molecules 2022, 27(13), 4249; https://doi.org/10.3390/molecules27134249 - 30 Jun 2022

Cited by 12 | Viewed by 6158

Abstract

Microwave-assisted synthesis is considered environmental-friendly and, therefore, in agreement with the principles of green chemistry. This form of energy has been employed extensively and successfully in organic synthesis also in the case of metal-catalyzed synthetic procedures. However, it has been less widely exploited [...] Read more.

Microwave-assisted synthesis is considered environmental-friendly and, therefore, in agreement with the principles of green chemistry. This form of energy has been employed extensively and successfully in organic synthesis also in the case of metal-catalyzed synthetic procedures. However, it has been less widely exploited in the synthesis of metal complexes. As microwave irradiation has been proving its utility as both a time-saving procedure and an alternative way to carry on tricky transformations, its use can help inorganic chemists, too. This review focuses on the use of microwave irradiation in the preparation of transition metal complexes and organometallic compounds and also includes new, unpublished results. The syntheses of the compounds are described following the group of the periodic table to which the contained metal belongs. A general overview of the results from over 150 papers points out that microwaves can be a useful synthetic tool for inorganic chemists, reducing dramatically the reaction times with respect to traditional heating. This is often accompanied by a more limited risk of decomposition of reagents or products by an increase in yield, purity, and (sometimes) selectivity. In any case, thermal control is operative, whereas nonthermal or specific microwave effects seem to be absent. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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28 pages, 5870 KiB

Open AccessReview

Heteroligand Metal Complexes with Extended Redox Properties Based on Redox-Active Chelating Ligands of o-Quinone Type and Ferrocene

by Svetlana V. Baryshnikova and Andrey I. Poddel’sky

Molecules 2022, 27(12), 3928; https://doi.org/10.3390/molecules27123928 - 19 Jun 2022

Cited by 4 | Viewed by 2188

Abstract

A combination of different types of redox-active systems in one molecule makes it possible to create coordination compounds with extended redox abilities, combining molecular and electronic structures determined by the features of intra- and intermolecular interactions between such redox-active centres. This review summarizes [...] Read more.

A combination of different types of redox-active systems in one molecule makes it possible to create coordination compounds with extended redox abilities, combining molecular and electronic structures determined by the features of intra- and intermolecular interactions between such redox-active centres. This review summarizes and analyses information from the literature, published mainly from 2000 to the present, on the methods of preparation, the molecular and electronic structure of mixed-ligand coordination compounds based on redox-active ligands of the o-benzoquinone type and ferrocenes, ferrocene-containing ligands, the features of their redox properties, and some chemical behaviour. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Inorganic Chemistry Section of Molecules)

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