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18 pages, 3111 KiB

Open AccessArticle

Synthesis, Structural Investigations, and In Vitro/In Silico Bioactivities of Flavonoid Substituted Biguanide: A Novel Schiff Base and Its Diorganotin (IV) Complexes

by Zahoor Abbas, Manoj Kumar, Hardeep Singh Tuli, Essam M. Janahi, Shafiul Haque, Steve Harakeh, Kuldeep Dhama, Pallvi Aggarwal, Mehmet Varol, Anita Rani and Shashi Sharma

Molecules 2022, 27(24), 8874; https://doi.org/10.3390/molecules27248874 - 14 Dec 2022

Cited by 4 | Viewed by 1837

Abstract

Quercetin is one of the most powerful bioactive dietary flavonoids. The in vivo biological study of quercetin is extremely difficult due to its very low solubility. However, diorganotin complexes of quercetin are more useful when contrasted with quercetin due to increased solubility. In [...] Read more.

Quercetin is one of the most powerful bioactive dietary flavonoids. The in vivo biological study of quercetin is extremely difficult due to its very low solubility. However, diorganotin complexes of quercetin are more useful when contrasted with quercetin due to increased solubility. In the present study, quercetin, substituted biguanide synthesized in the form of Schiff base and its di-alkyl/aryl tin (IV) complexes were obtained by condensing Schiff base with respective di-alkyl/aryl tin (IV) dichloride. Advanced analytical techniques were used for structural elucidation. The results of biological screening against Gram-positive/Gram-negative bacteria and fungi showed that these diorganotin (IV) derivatives act as potent antimicrobial agents. The in silico investigation with dihydropteroate (DHPS) disclosed a large ligand–receptor interaction and revealed a strong relationship between the natural exercises and computational molecular docking results. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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16 pages, 3408 KiB

Open AccessArticle

RE^(III) 3-Furoate Complexes: Synthesis, Structure, and Corrosion Inhibiting Properties

by Vidushi P. Vithana, Zhifang Guo, Glen B. Deacon, Anthony E. Somers and Peter C. Junk

Molecules 2022, 27(24), 8836; https://doi.org/10.3390/molecules27248836 - 13 Dec 2022

Cited by 3 | Viewed by 1574

Abstract

In this study, two types of Rare Earth (RE) 3-furoate complexes were synthesized by metathesis reactions between RE chlorides or nitrates and preformed sodium 3-furoate. Two different structural motifs were identified as Type 1RE and Type 2RE. The Type 1RE monometallic complexes [...] Read more.

In this study, two types of Rare Earth (RE) 3-furoate complexes were synthesized by metathesis reactions between RE chlorides or nitrates and preformed sodium 3-furoate. Two different structural motifs were identified as Type 1RE and Type 2RE. The Type 1RE monometallic complexes form 2D polymeric networks with the composition [RE(3fur)₃(H₂O)₂]_n (1RE = 1La, 1Ce, 1Pr, 1Nd, 1Gd, 1Dy, 1Ho, 1Y; 3furH = 3-furoic acid) while Type 2RE bimetallic complexes form 3D polymeric systems [NaRE(3fur)₄]_n (2RE = 2Ho, 2Y, 2Er, 2Yb, 2Lu). The stoichiometric mole ratio used (RE: Na(3fur) = 1:3 or 1:4) in the metathesis reaction determines whether 1RE or 2RE (RE = Ho or Y) is formed, but 2RE (RE = Er, Yb, Lu) were obtained regardless of the ratio. The corrosion inhibition behaviour of the compounds has been examined using immersion studies and electrochemical measurements on AS1020 mild steel surfaces by a 0.01 M NaCl medium. Immersion test results revealed that [Y(3fur)₃(H₂O)₂]_n has the highest corrosion inhibition capability with 90% resistance after 168 h of immersion. Potentiodynamic polarisation (PP) measurements also indicate the dominant behaviour of the 1Y compound, and the PP curves show that these rare earth carboxylate compounds act predominantly as anodic inhibitors. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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12 pages, 2119 KiB

Open AccessArticle

Stability of Dibromo-Dipyrromethene Complexes Coordinated with B, Zn, and Cd in Solutions of Various Acidities

by Iuliia Aksenova and Vladimir Pomogaev

Molecules 2022, 27(24), 8815; https://doi.org/10.3390/molecules27248815 - 12 Dec 2022

Viewed by 1117

Abstract

The spectral luminescent properties of dipyrromethenates halogenated with bromine on both ends of the long axis and coordinated using boron fluoride, zinc, or cadmium in neutral ethanol and acidified with hydrochloric acid solutions were studied. The constants of the acid–base equilibrium of the [...] Read more.

The spectral luminescent properties of dipyrromethenates halogenated with bromine on both ends of the long axis and coordinated using boron fluoride, zinc, or cadmium in neutral ethanol and acidified with hydrochloric acid solutions were studied. The constants of the acid–base equilibrium of the complexes in the proton-donor solvents in the ground and excited states was determined. The mechanisms of complex protonation were discussed, depending on the structure of the compounds. The electronic structures of the neutral and protonated compounds were modeled and analyzed based on the quantum-chemical method. The structures and spectral-luminescence properties were calculated using the SMD model of ethanol solvent using the TD-DFT theory with the B3LYP functional and the composite def2-SVP/def2-TZVP/def2-TZVPP_ECP basis sets, depending on the atomic number of the elements. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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12 pages, 2046 KiB

Open AccessFeature PaperArticle

Multicolor Emissive Phosphorescent Iridium(III) Complexes Containing L-Alanine Ligands: Photophysical and Electrochemical Properties, DFT Calculations, and Selective Recognition of Cu(II) Ions

by Xi Chu, Yichuan Huang, Wenhao Li, Shisheng Zhao, Hongyan Li and Aidang Lu

Molecules 2022, 27(23), 8506; https://doi.org/10.3390/molecules27238506 - 3 Dec 2022

Cited by 3 | Viewed by 1310

Abstract

Three novel Ir(III) complexes, (ppy)₂Ir(L-alanine) (Ir1) (ppy = 2-phenylpyridine), (F₄ppy)₂Ir(L-alanine) (Ir2) (F₄ppy = 2-(4-fluorophenyl)pyridine), and (F_2,4,5ppy)₂Ir(L-alanine) (Ir3) (F_2,4,5ppy = 2-(2,4,5-trifluorophenyl)pyridine), based on simple [...] Read more.

Three novel Ir(III) complexes, (ppy)₂Ir(L-alanine) (Ir1) (ppy = 2-phenylpyridine), (F₄ppy)₂Ir(L-alanine) (Ir2) (F₄ppy = 2-(4-fluorophenyl)pyridine), and (F_2,4,5ppy)₂Ir(L-alanine) (Ir3) (F_2,4,5ppy = 2-(2,4,5-trifluorophenyl)pyridine), based on simple L-alanine as ancillary ligands were synthesized and investigated. Due to the introduction of fluorine substituents on the cyclometalated ligands, complexes Ir1–Ir3 exhibited yellow to sky-blue emissions (λ_em = 464–509 nm) in acetonitrile solution. The photoluminescence quantum yields (PLQYs) of Ir1–Ir3 ranged from 0.48–0.69, of which Ir3 with sky-blue luminescence had the highest PLQY of 0.69. The electrochemical study and density functional theory (DFT) calculations show that the highest occupied molecular orbital (HOMOs) energy of Ir1–Ir3 are stabilized by the introduction of fluorine substituents on the cyclometalated ligands, while L-alanine ancillary ligand has little contribution to HOMOs and lowest unoccupied molecular orbitals (LUMOs). Moreover, Ir1–Ir3 presented an excellent response to Cu²⁺ with a high selectivity, strong anti-interference ability, and short response time. Such a detection was based on significant phosphorescence quenching of their emissions, showing the potential application in chemosensors for Cu²⁺. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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17 pages, 3217 KiB

Open AccessArticle

Coordination Polymers of Polyphenyl-Substituted Potassium Cyclopentadienides

by Pavel D. Komarov, Kirill P. Birin, Alexander A. Vinogradov, Evgenia A. Varaksina, Lada N. Puntus, Konstantin A. Lyssenko, Andrei V. Churakov, Ilya E. Nifant’ev, Mikhail E. Minyaev and Dmitrii M. Roitershtein

Molecules 2022, 27(22), 7725; https://doi.org/10.3390/molecules27227725 - 9 Nov 2022

Viewed by 1409

Abstract

A series of potassium salts of di- and tri-arylsubstituted cyclopentadienes has been obtained by the metalation of the corresponding cyclopentadienes with benzylpotassium in THF media. Crystals of all compounds, afforded by recrystallization from THF/hexane, diglyme-THF/hexane and toluene/hexane mixtures, have been studied by X-ray [...] Read more.

A series of potassium salts of di- and tri-arylsubstituted cyclopentadienes has been obtained by the metalation of the corresponding cyclopentadienes with benzylpotassium in THF media. Crystals of all compounds, afforded by recrystallization from THF/hexane, diglyme-THF/hexane and toluene/hexane mixtures, have been studied by X-ray diffraction. All studied potassium cyclopentadienides exhibit the luminescence at room temperature and overall quantum yield of photoluminescence for potassium salt of diarylsubstituted cyclopentadiene is 18%. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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14 pages, 2724 KiB

Open AccessArticle

Synthesis and Characterisation of Novel Bis(diphenylphosphane oxide)methanidoytterbium(III) Complexes

by Shalini Rangarajan, Owen A. Beaumont, Maravanji S. Balakrishna, Glen B. Deacon and Victoria L. Blair

Molecules 2022, 27(22), 7704; https://doi.org/10.3390/molecules27227704 - 9 Nov 2022

Cited by 1 | Viewed by 1166

Abstract

Reaction of [YbCp₂(dme)] (Cp = cyclopentadienyl, dme = 1,2 dimethoxyethane) with bis(diphenylphosphano)methane dioxide (H₂dppmO₂) leads to deprotonation of the ligand H₂dppmO₂ and oxidation of ytterbium, forming an extremely air-sensitive product, [Yb^III(HdppmO₂ [...] Read more.

Reaction of [YbCp₂(dme)] (Cp = cyclopentadienyl, dme = 1,2 dimethoxyethane) with bis(diphenylphosphano)methane dioxide (H₂dppmO₂) leads to deprotonation of the ligand H₂dppmO₂ and oxidation of ytterbium, forming an extremely air-sensitive product, [Yb^III(HdppmO₂)₃] (1), a six-coordinate complex with three chelating (OPCHPO) HdppmO₂ ligands. Complex 1 was also obtained by a redox transmetallation/protolysis synthesis from metallic ytterbium, Hg(C₆F₅)_2, and H₂dppmO₂. In a further preparation, the reaction of [Yb(C₆F₅)₂] with H₂dppmO₂, not only yielded compound 1, but also gave a remarkable tetranuclear cage, [Yb₄(µ-HdppmO₂)₆(µ-F)₆] (2) containing two [Yb(µ-F)]₂ rhombic units linked by two fluoride ligands and the tetranuclear unit is encapsulated by six bridging HdppmO₂ donors. The fluoride ligands of the cage result from C-F activation of pentafluorobenzene and concomitant formation of p-H₂C₆F₄ and m-H₂C₆F₄, the last being an unexpected product. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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8 pages, 1063 KiB

Open AccessArticle

Synthesis, Characterization, and X-ray Crystallography, of the First Cyclohexadienyl Trifluoromethyl Metal Complex (η⁵-C₆H₇)Fe(CO)₂CF₃

by Chris Douvris, David Matatov, Derek Bussan, Christos Lampropoulos and Donald J. Wink

Molecules 2022, 27(21), 7595; https://doi.org/10.3390/molecules27217595 - 5 Nov 2022

Viewed by 1853

Abstract

Fluorochemistry is a field of tremendous developments and advances in several areas of science including materials, pharmaceuticals and agriculture. This makes the design and synthesis of fluorine-containing substances highly desirable research targets. The sub-area of synthetic perfluorinated chemistry proportionately attracts widespread interest by [...] Read more.

Fluorochemistry is a field of tremendous developments and advances in several areas of science including materials, pharmaceuticals and agriculture. This makes the design and synthesis of fluorine-containing substances highly desirable research targets. The sub-area of synthetic perfluorinated chemistry proportionately attracts widespread interest by applying to all areas of chemistry including organic and inorganic. Particularly, the latter is much underdeveloped as metal complexes with perfluoroalkyl moieties are scarce, with the vast majority of perfluorinated analogs, of long known, halo and alkylated derivatives never having been synthesized. Focusing on the chemistry of trifluoromethyl group, which is the most important in the class of perfluoroalkyls, we set out to explore the possibility of synthesizing and completely characterizing a cyclohexadienyl metal complex. Upon utilizing a number of trifluorometylating reagents, we only arrived at an efficient preparation by the use of Morrison’s trifluormethylating reagent. As a result, the new, air- and moisture-sensitive complex (η⁵-C₆H₇)Fe(CO)₂CF₃, was prepared in 71% yield, using a nucleophilic iodo-for-trifluoromethyl substitution, and was completely characterized including by X-ray crystallography. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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10 pages, 1757 KiB

Open AccessCommunication

Reinvestigation of Reactions of HgPh₂ with Eu and Yb Metal and the Synthesis of a Europium(II) Bis(tetraphenylborate)

by Michal Wiecko, Zhifang Guo, Glen B. Deacon and Peter C. Junk

Molecules 2022, 27(21), 7547; https://doi.org/10.3390/molecules27217547 - 3 Nov 2022

Cited by 1 | Viewed by 1322

Abstract

Europium bis(tetraphenylborate) [Eu(thf)₇][BPh₄]₂⋅thf containing a fully solvated [Eu(thf)₇]²⁺ cation, was synthesized by protolysis of “EuPh₂” (from Eu and HgPh₂) with Et₃NHBPh₄, and the structure was determined [...] Read more.

Europium bis(tetraphenylborate) [Eu(thf)₇][BPh₄]₂⋅thf containing a fully solvated [Eu(thf)₇]²⁺ cation, was synthesized by protolysis of “EuPh₂” (from Eu and HgPh₂) with Et₃NHBPh₄, and the structure was determined by single-crystal X-ray diffraction. Efforts to characterize the putative “Ph₂Ln” (Ln = Eu, Yb) reagents led to the synthesis of a mixed-valence complex, [(thf)₃Yb^II(μ-Ph)₃Yb^III(Ph)₂(thf)]⋅2thf, resulting from the reaction of Yb metal with HgPh₂ at a low temperature. This mixed-valence Yb^II/Yb^III compound was studied by ¹⁷¹Yb-NMR spectroscopy and single-crystal X-ray diffraction, and the oxidation states of the Yb atoms were assigned. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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11 pages, 2905 KiB

Open AccessArticle

2-Imidazoline Nitroxide Derivatives of Cymantrene

by Kseniya Maryunina, Gleb Letyagin, Galina Romanenko, Artem Bogomyakov, Vitaly Morozov, Sergey Tumanov, Sergey Veber, Matvey Fedin, Evgeniya Saverina, Mikhail Syroeshkin, Mikhail Egorov and Victor Ovcharenko

Molecules 2022, 27(21), 7545; https://doi.org/10.3390/molecules27217545 - 3 Nov 2022

Viewed by 1808

Abstract

The 2-imidazoline nitroxide derivatives of cymantrene—2-(η⁵-cyclopentadienyl)tricarbonylmanganese(I)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (NNMn) and 2-(η⁵-cyclopentadienyl)tricarbonylmanganese(I)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl (INMn) were synthesized. It was shown that NNMn and INMn exhibit a sufficiently high kinetic stability both in solids and in solutions under normal [...] Read more.

The 2-imidazoline nitroxide derivatives of cymantrene—2-(η⁵-cyclopentadienyl)tricarbonylmanganese(I)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl (NNMn) and 2-(η⁵-cyclopentadienyl)tricarbonylmanganese(I)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl (INMn) were synthesized. It was shown that NNMn and INMn exhibit a sufficiently high kinetic stability both in solids and in solutions under normal conditions. Their structural characteristics, magnetic properties and electrochemical behavior are close to Re(I) analogs. This opens the prospect of using paramagnetic cymantrenes as prototypes in the design of Re(I) half-sandwiched derivatives for theranostics, where therapy is combined with diagnostics by magnetic resonance imaging due to the contrast properties of nitroxide radicals. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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16 pages, 9287 KiB

Open AccessArticle

Luminescent Hybrid Material Based on Boron Organic Phosphor and Silica Aerogel Matrix

by Roman Avetisov, Artem Lebedev, Ekaterina Suslova, Ksenia Kazmina, Kristina Runina, Vlada Kovaleva, Andrew Khomyakov, Artem Barkanov, Marina Zykova, Olga Petrova, Alisa Mukhsinova, Denis Shepel, Artyom Astafiev, Natalia Menshutina and Igor Avetissov

Molecules 2022, 27(16), 5226; https://doi.org/10.3390/molecules27165226 - 16 Aug 2022

Cited by 2 | Viewed by 1487

Abstract

A new luminescent hybrid material based on silica aerogel and a boron-containing coordination compound with 8-hydroxyquinoline was created, and its physicochemical and spectral-luminescent characteristics were studied. A simple scheme for the synthesis of a hybrid luminescent material was developed. Simultaneously with the synthesis [...] Read more.

A new luminescent hybrid material based on silica aerogel and a boron-containing coordination compound with 8-hydroxyquinoline was created, and its physicochemical and spectral-luminescent characteristics were studied. A simple scheme for the synthesis of a hybrid luminescent material was developed. Simultaneously with the synthesis of the aerogel, the formation of a boron-containing phosphor was carried out using an isopropanol solution of boric acid and 8-hydroxyquinoline. Using in situ luminescent measurements, the mechanisms of the formation of boron-based luminescent complexes in isopropanol and tetrahydrofuran media were established. Both hydrophilic and hydrophobic silica aerogels were tested as matrices for the hybrid material. The formation of a thin layer of a boron-containing coordination luminescent compound on the highly developed surface of the SiO₂ aerogel made it possible to strongly stabilize the aerogel structure and noticeably increase the thermal stability of the synthesized hybrid material. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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14 pages, 6121 KiB

Open AccessArticle

Size-Induced Highly Selective Synthesis of Organometallic Rectangular Macrocycles and Heterometallic Cage Based on Half-Sandwich Rhodium Building Block

by Li-Long Dang, Tian Chen, Ting-Ting Zhang, Ting-Ting Li, Jun-Liang Song, Ke-Jia Zhang and Lu-Fang Ma

Molecules 2022, 27(12), 3756; https://doi.org/10.3390/molecules27123756 - 10 Jun 2022

Cited by 6 | Viewed by 1985

Abstract

The controlled synthesis of organometallic supramolecular macrocycles cages remains interesting and challenging work in the field of supramolecular chemistry. Here, two tetranuclear rectangular macrocycles and an octuclear cage were designed and synthesized utilizing a rigid and functionalized pillar linker, 2,6-bis(pyridin-4-yl)-1,7-dihydrobenzo [1,2-d:4,5-d′]diimidazole (BBI4PY) based [...] Read more.

The controlled synthesis of organometallic supramolecular macrocycles cages remains interesting and challenging work in the field of supramolecular chemistry. Here, two tetranuclear rectangular macrocycles and an octuclear cage were designed and synthesized utilizing a rigid and functionalized pillar linker, 2,6-bis(pyridin-4-yl)-1,7-dihydrobenzo [1,2-d:4,5-d′]diimidazole (BBI4PY) based on three half-sandwich rhodium building blocks bearing different sizes. X-ray crystallography in combination with ¹H NMR spectroscopy elucidated that the two building blocks with shorter spacers only result in rectangular macrocycles. However, the building block of bulkier size to avoid the π-π stacking interactions between two ligands BBI4PY led to the formation of an octuclear cage complex. The latter cage contains two types of metal ions, namely Rh³⁺ and Cu²⁺, showing significant characteristics of heterogeneous metal-assembling compounds. In addition, the cage accommodates two free isopropyl ether solvent molecules, thus displaying host–guest behavior. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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Review

Jump to: Research

43 pages, 26414 KiB

Open AccessFeature PaperReview

Heterometallic Molecular Architectures Based on Fluorinated β-Diketone Ligands

by Viktor I. Saloutin, Yulia O. Edilova, Yulia S. Kudyakova, Yanina V. Burgart and Denis N. Bazhin

Molecules 2022, 27(22), 7894; https://doi.org/10.3390/molecules27227894 - 15 Nov 2022

Cited by 11 | Viewed by 2350

Abstract

This review summarizes the data on the synthesis of coordination compounds containing two or more different metal ions based on fluorinated β-diketonates. Heterometallic systems are of high interest in terms of their potential use in catalysis, medicine and diagnostics, as well as in [...] Read more.

This review summarizes the data on the synthesis of coordination compounds containing two or more different metal ions based on fluorinated β-diketonates. Heterometallic systems are of high interest in terms of their potential use in catalysis, medicine and diagnostics, as well as in the development of effective sensor devices and functional materials. Having a rich history in coordination chemistry, fluorinated β-diketones are well-known ligands generating a wide variety of heterometallic complexes. In this context, we focused on both the synthetic approaches to β-dicarbonyl ligands with additional coordination centers and their possible transformations in complexation reactions. The review describes bi- and polynuclear structures in which β-diketones are the key building blocks in the formation of a heterometallic framework, including the examples of both homo- and heteroleptic complexes. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Applications of Organometallic Complexes)

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