Molecules

Research

Jump to: Review

15 pages, 5078 KiB

Open AccessArticle

Sodium β-Diketonate Glyme Adducts as Precursors for Fluoride Phases: Synthesis, Characterization and Functional Validation

by Nishant Peddagopu, Anna L. Pellegrino, Carmela Bonaccorso, Patrizia Rossi, Paola Paoli and Graziella Malandrino

Molecules 2022, 27(19), 6282; https://doi.org/10.3390/molecules27196282 - 23 Sep 2022

Cited by 5 | Viewed by 1444

Abstract

Very few sodium complexes are available as precursors for the syntheses of sodium-based nanostructured materials. Herein, the diglyme, triglyme, and tetraglyme (CH₃O(CH₂CH₂O)_nCH₃, n = 2–4) adducts of sodium hexafluoroacetylacetonate were synthesized in a [...] Read more.

Very few sodium complexes are available as precursors for the syntheses of sodium-based nanostructured materials. Herein, the diglyme, triglyme, and tetraglyme (CH₃O(CH₂CH₂O)_nCH₃, n = 2–4) adducts of sodium hexafluoroacetylacetonate were synthesized in a single-step reaction and characterized by IR spectroscopy, ¹H, and ¹³C NMR. Single-crystal X-ray diffraction studies provide evidence of the formation of the ionic oligomeric structure [Na₄(hfa)₆]²⁻•2[Na(diglyme₂]⁺ when the diglyme is coordinated, while a mononuclear seven-coordinated complex Na(hfa)•tetraglyme is formed with the tetraglyme. Reaction with the monoglyme (CH₃OCH₂CH₂OCH₃) does not occur, and the unadducted polymeric structure [Na(hfa)]_n forms, while the triglyme gives rise to a liquid adduct, Na(hfa)•triglyme•H₂O. Thermal analysis data reveal great potentialities for their applications as precursors in metalorganic chemical vapor deposition (MOCVD) and sol-gel processes. As a proof-of-concept, the Na(hfa)•tetraglyme adduct was successfully applied to both the low-pressure MOCVD and the sol-gel/spin-coating synthesis of NaF films. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

13 pages, 1999 KiB

Open AccessArticle

High-Temperature Spin Crossover in Iron(II) Complexes with 2,6-Bis(1H-imidazol-2-yl)pyridine

by Ludmila G. Lavrenova, Olga G. Shakirova, Evgeniy V. Korotaev, Svetlana V. Trubina, Alexsei Ya. Tikhonov, Irina A. Os’kina, Sergey A. Petrov, Konstantin Yu. Zhizhin and Nikolay T. Kuznetsov

Molecules 2022, 27(16), 5093; https://doi.org/10.3390/molecules27165093 - 10 Aug 2022

Cited by 5 | Viewed by 2099

Abstract

Novel iron(II) coordination compounds containing a ligand 2,6-bis(1H-imidazol-2-yl)pyridine (L), having such a composition as [FeL₂]SO₄·0.5H₂O, [FeL₂]Br₂·H₂O, [FeL₂](ReO₄)₂, [FeL₂]B₁₀H₁₀ [...] Read more.

Novel iron(II) coordination compounds containing a ligand 2,6-bis(1H-imidazol-2-yl)pyridine (L), having such a composition as [FeL₂]SO₄·0.5H₂O, [FeL₂]Br₂·H₂O, [FeL₂](ReO₄)₂, [FeL₂]B₁₀H₁₀∙H₂O, [FeL₂]B₁₂H₁₂∙1.5H₂O had been synthesized and studied using UV-Vis (diffuse reflectance), infrared, extended X-ray absorption fine structure (EXAFS), and Mössbauer spectroscopy methods, as well as X-ray diffraction and static magnetic susceptibility methods. The analysis of the μ_eff(T) dependence in the temperature range of 80–600 K have shown that all the obtained complexes exhibit a high-temperature spin crossover ¹A₁ ↔ ⁵T₂. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

17 pages, 1818 KiB

Open AccessArticle

Theoretical Approach for the Luminescent Properties of Ir(III) Complexes to Produce Red–Green–Blue LEC Devices

by Mireya Santander-Nelli, Bastián Boza, Felipe Salas, David Zambrano, Luis Rosales and Paulina Dreyse

Molecules 2022, 27(9), 2623; https://doi.org/10.3390/molecules27092623 - 19 Apr 2022

Cited by 4 | Viewed by 2266

Abstract

With an appropriate mixture of cyclometalating and ancillary ligands, based on simple structures (commercial or easily synthesized), it has been possible to design a family of eight new Ir(III) complexes (1A, 1B, 2B, 2C, 3B, 3C, 3D [...] Read more.

With an appropriate mixture of cyclometalating and ancillary ligands, based on simple structures (commercial or easily synthesized), it has been possible to design a family of eight new Ir(III) complexes (1A, 1B, 2B, 2C, 3B, 3C, 3D and 3E) useful as luminescent materials in LEC devices. These complexes involved the use of phenylpyridines or fluorophenylpyridines as cyclometalating ligands and bipyridine or phenanthroline-type structures as ancillary ligands. The emitting properties have been evaluated from a theoretical approach through Density Functional Theory and Time-Dependent Density Functional Theory calculations, determining geometric parameters, frontier orbital energies, absorption and emission energies, injection and transport parameters of holes and electrons, and parameters associated with the radiative and non-radiative decays. With these complexes it was possible to obtain a wide range of emission colours, from deep red to blue (701–440 nm). Considering all the calculated parameters between all the complexes, it was identified that 1B was the best red, 2B was the best green, and 3D was the best blue emitter. Thus, with the mixture of these complexes, a dual host–guest system with 3D-1B and an RGB (red–green–blue) system with 3D-2B-1B are proposed, to produce white LECs. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Figure 1

19 pages, 5294 KiB

Open AccessArticle

The Theoretical and Experimental Investigation of the Fluorinated Palladium β-Diketonate Derivatives: Structure and Physicochemical Properties

by Svetlana I. Dorovskikh, Denis E. Tryakhov, Darya D. Klyamer, Alexander S. Sukhikh, Irina V. Mirzaeva, Natalia B. Morozova and Tamara V. Basova

Molecules 2022, 27(7), 2207; https://doi.org/10.3390/molecules27072207 - 28 Mar 2022

Viewed by 2193

Abstract

To search for new suitable Pd precursors for MOCVD/ALD processes, the extended series of fluorinated palladium complexes [Pd(CH₃CXCHCO(R))₂] with β-diketone [tfa−1,1,1-trifluoro-2,4-pentanedionato (1); pfpa−5,5,6,6,6-pentafluoro-2,4-hexanedionato (3); hfba−5,5,6,6,7,7,7-heptafluoro-2,4-heptanedionato (5)] and β-iminoketone [i-tfa−1,1,1-trifluoro-2-imino-4-pentanonato (2); i-pfpa−5,5,6,6,6-pentafluoro-2-imino-4-hexanonato [...] Read more.

To search for new suitable Pd precursors for MOCVD/ALD processes, the extended series of fluorinated palladium complexes [Pd(CH₃CXCHCO(R))₂] with β-diketone [tfa−1,1,1-trifluoro-2,4-pentanedionato (1); pfpa−5,5,6,6,6-pentafluoro-2,4-hexanedionato (3); hfba−5,5,6,6,7,7,7-heptafluoro-2,4-heptanedionato (5)] and β-iminoketone [i-tfa−1,1,1-trifluoro-2-imino-4-pentanonato (2); i-pfpa−5,5,6,6,6-pentafluoro-2-imino-4-hexanonato (4); i-hfba-5,5,6,6,7,7,7-heptafluoro-2-imino-4-heptanonato (6)] ligands were synthesized with 70–80% yields and characterized by a set of experimental (SXRD, XRD, IR, NMR spectroscopy, TG) and theoretical (DFT, Hirshfeld surface analysis) methods. Solutions of Pd β-diketonates contained both cis and trans isomers, while only trans isomers were detected in the solutions of Pd β-iminoketonates. The molecules 2–6 and new polymorphs of complexes 3 and 5 were arranged preferentially in stacks, and the distance between molecules in the stack generally increased with elongation of the fluorine chain in ligands. The H…F contacts were the main ones involved in the formation of packages of molecules 1–2, and C…F, F…F, NH…F contacts appeared in the structures of complexes 4–6. The stability of complexes and their polymorphs in the crystal phases were estimated from DFT calculations. The TG data showed that the volatility differences between Pd β-iminoketonates and Pd β-diketonates were minimized with the elongation of the fluorine chain in the ligands. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

6 pages, 538 KiB

Open AccessCommunication

The Synthesis and Structure of a Scandium Nitrate Hydroxy-Bridged Dimeric Complex Supported by Bipyridyl Ligands

by Simon A. Cotton, Paul R. Raithby, Stephanie Schiffers, Simon J. Teat and John E. Warren

Molecules 2022, 27(6), 2024; https://doi.org/10.3390/molecules27062024 - 21 Mar 2022

Viewed by 2081

Abstract

The current discussion on whether scandium, yttrium and lanthanum should represent Group 3 in the Periodic Table or whether lutetium should replace lanthanum in the group has prompted us to further explore the structural chemistry of the Group 3 elements and compare the [...] Read more.

The current discussion on whether scandium, yttrium and lanthanum should represent Group 3 in the Periodic Table or whether lutetium should replace lanthanum in the group has prompted us to further explore the structural chemistry of the Group 3 elements and compare the coordination numbers and coordination geometries adopted. The steric and electronic properties of the coordinated ligands have a major influence on the structures adopted. We report the synthesis and crystal structure determination of an unusual dinuclear scandium complex [(bipy)(NO₃)₂Sc(µ-OH)₂Sc(NO₃)₂(bipy)] obtained by the reaction of hydrated scandium nitrate with 2,2′-bipyridyl (bipy) in either ethanol or nitromethane. The crystal structure of the complex shows that the scandium centers are eight coordinate, and the structure obtained contrasts with related complexes found in the lanthanide series [Ln(bipy)₂(NO₃)₃] and [Ln(phen)₂(NO₃)₃] (phen = phenanthroline) and in [M(terpy)(NO₃)₃] (M = Sc, Er–Lu), where these complexes are all mononuclear. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Figure 1

21 pages, 14150 KiB

Open AccessArticle

The Influence of Electrolyte Type on Kinetics of Redox Processes in the Polymer Films of Ni(II) Salen-Type Complexes

by Danuta Tomczyk, Piotr Seliger, Wiktor Bukowski and Karol Bester

Molecules 2022, 27(6), 1812; https://doi.org/10.3390/molecules27061812 - 10 Mar 2022

Cited by 3 | Viewed by 1921

Abstract

Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and [...] Read more.

Electrodes modified with polymers derived from the complexes [Ni(salcn)], [Ni(salcn(Me))] and [Ni(salcn(Bu))] were obtained in order to study the kinetics of electrode processes occurring in polymer films, depending on the thickness of the films, the type of electrolyte and the solvent. FTIR and EQCM methods were used to determine the type of mass transported into polymer films during anode processes and the number of moles of ions and solvent. The rate of charge transport through films was determined by the cyclic voltammetry method, by the quantity cD^1/2. It was shown that the charge transport was determined by the transport of anions. The kinetics were most efficient for poly[Ni(salcn(Bu))] modified electrodes, obtained from TBAPF₆ and working in TBAClO₄ and TBABF₄. It was also shown that a solvent with a higher DN value and lower viscosity (MeCN) facilitated the transport of the charge through polymer films. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Figure 1

11 pages, 1362 KiB

Open AccessArticle

Zn(II) and Co(II) 3D Coordination Polymers Based on 2-Iodoterephtalic Acid and 1,2-bis(4-pyridyl)ethane: Structures and Sorption Properties

by Alexander S. Zaguzin, Taisiya S. Sukhikh, Ilyas F. Sakhapov, Vladimir P. Fedin, Maxim N. Sokolov and Sergey A. Adonin

Molecules 2022, 27(4), 1305; https://doi.org/10.3390/molecules27041305 - 15 Feb 2022

Cited by 9 | Viewed by 2425

Abstract

Metal-organic frameworks [M₂(2-I-bdc)₂bpe] (M = Zn(II) (1), Co(II) (2), 2-I-bdc = 2-iodoterephtalic acid, and bpe = 1,2-bis(4-pyridyl)ethane) were prepared and characterized by X-ray diffractometry. Both compounds retain their 3D structure after the removal of guest [...] Read more.

Metal-organic frameworks [M₂(2-I-bdc)₂bpe] (M = Zn(II) (1), Co(II) (2), 2-I-bdc = 2-iodoterephtalic acid, and bpe = 1,2-bis(4-pyridyl)ethane) were prepared and characterized by X-ray diffractometry. Both compounds retain their 3D structure after the removal of guest DMF molecules. Selectivity of sorption of different organic substrates from the gas phase was investigated for both complexes. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Figure 1

15 pages, 3323 KiB

Open AccessArticle

Formation of Catalytically Active Nanoparticles under Thermolysis of Silver Chloroplatinate(II) and Chloroplatinate(IV)

by Evgeny Filatov, Pavel Smirnov, Dmitry Potemkin, Denis Pishchur, Natalya Kryuchkova, Pavel Plyusnin and Sergey Korenev

Molecules 2022, 27(4), 1173; https://doi.org/10.3390/molecules27041173 - 9 Feb 2022

Cited by 3 | Viewed by 1853

Abstract

The thermal behaviour of Ag₂[PtCl₄] and Ag₂[PtCl₆] complex salts in inert and reducing atmospheres has been studied. The thermolysis of compounds in a helium atmosphere is shown to occur in two stages. At the first [...] Read more.

The thermal behaviour of Ag₂[PtCl₄] and Ag₂[PtCl₆] complex salts in inert and reducing atmospheres has been studied. The thermolysis of compounds in a helium atmosphere is shown to occur in two stages. At the first stage, the complexes decompose in the temperature range of 350–500 °C with the formation of platinum and silver chloride and the release of chlorine gas. At the second stage, silver chloride is sublimated in the temperature range of 700–900 °C, while metallic platinum remains in the solid phase. In contrast to the thermolysis of Ag₂[PtCl₆], the thermal decomposition of Ag₂[PtCl₄] at 350 °C is accompanied by significant heat release, which is associated with disproportionation of the initial salt to Ag₂[PtCl₆], silver chloride, and platinum metal. It is confirmed by DSC measurements, DFT calculations of a suggested reaction, and XRD. The thermolysis of Ag₂[PtCl₄] and Ag₂[PtCl₆] compounds is shown to occur in a hydrogen atmosphere in two poorly separable steps. The compounds are decomposed within 170–350 °C, and silver and platinum are reduced to a metallic state, while a metastable single-phase solid solution of Ag_0.67Pt_0.33 is formed. The catalytic activity of the resulting nanoalloy Ag_0.67Pt_0.33 is studied in the reaction of CO total (TOX) and preferential (PROX) oxidation. Ag_0.67Pt_0.33 enhanced Pt nano-powder activity in CO TOX, but was not selective in CO PROX. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Figure 1

15 pages, 5293 KiB

Open AccessArticle

Structural Diversity of Silver Fluorinated β-Diketonates: Effect of the Terminal Substituent and Solvent

by Evgeniia S. Vikulova, Taisiya S. Sukhikh, Sergey A. Gulyaev, Igor Yu. Ilyin and Natalia B. Morozova

Molecules 2022, 27(3), 677; https://doi.org/10.3390/molecules27030677 - 20 Jan 2022

Cited by 6 | Viewed by 2042

Abstract

In order to demonstrate the role of the fluorination and some solvents in the structural organization of the Ag(I) coordination polymers with β-diketonate ligands (R¹C(O)C_αHC(O)R²)⁻ we synthesized a series of the compounds containing tfac- (R₁ [...] Read more.

In order to demonstrate the role of the fluorination and some solvents in the structural organization of the Ag(I) coordination polymers with β-diketonate ligands (R¹C(O)C_αHC(O)R²)⁻ we synthesized a series of the compounds containing tfac- (R₁ = CH₃, R² = CF₃) and pfpac- (R₁ = CH₃, R² = C₂F₅) anions. Solvent-free [Ag(L)]_∞ (L = tfac 1, pfpac 2) compounds and the corresponding acetonitrile and toluene adducts have been characterized by elemental analysis and/or NMR, IR and single-crystal XRD. This series includes five new coordination polymers. Compound 1 is a 3D coordination framework based on Ag–O_{chelate/bridge}, Ag–C_α bonds, and argentophilic interactions. An increase in the fluorinated group leads to a chain coordination polymer 2 of an unusual structural organization. These chains can be represented as a “DNA-type”, where two intertwined helices based on Ag–O_chelate and Ag–C_α bonds are connected through Ag–O_bridge ones. Two structural types of chain coordination polymers, [Ag(tfac)(CH₃CN)] and [Ag₂(L)₂(solvent)], have been revealed for the adducts. The latter structural type differs significantly from the previously studied toluene and acetonitrile adducts of fluorinated Ag(I) β-diketonates of the same stoichiometry. Thermal analysis in helium showed that both 1 and 2 decompose to metallic silver with the compound of pfpac-ligand being slightly more stable. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

20 pages, 2612 KiB

Open AccessArticle

Thallium(I) Tropolonates: Synthesis, Structure, Spectral Characteristics, and Antimicrobial Activity Compared to Lead(II) and Bismuth(III) Analogues

by Krzysztof Lyczko, Monika Lyczko, Marzena Banasiewicz, Karolina Wegrzynska, Anna Ziółko, Anna Baraniak and Jan Cz. Dobrowolski

Molecules 2022, 27(1), 183; https://doi.org/10.3390/molecules27010183 - 29 Dec 2021

Cited by 2 | Viewed by 2330

Abstract

Synthesis, single-crystal X-ray determination diffraction and FT-IR, NMR (¹H, ¹³C, ¹⁹F and ²⁰⁵Tl), UV–vis, and luminescence spectra characteristics were described for series of thallium(I) compounds: thallium(I) triflate (Tl(OTf)), 1:1 co-crystals of thallium(I) triflate and tropolone (Htrop), Tl(OTf)·Htrop, as [...] Read more.

Synthesis, single-crystal X-ray determination diffraction and FT-IR, NMR (¹H, ¹³C, ¹⁹F and ²⁰⁵Tl), UV–vis, and luminescence spectra characteristics were described for series of thallium(I) compounds: thallium(I) triflate (Tl(OTf)), 1:1 co-crystals of thallium(I) triflate and tropolone (Htrop), Tl(OTf)·Htrop, as well as simple thallium(I) chelates: Tl(trop) (1), Tl(5-metrop) (2), Tl(hino) (3), with Htrop, 5-methyltropolone (5-meHtrop), 4-isopropyltropolone (hinokitiol, Hhino), respectively, and additionally more complex {Tl@[Tl(hino)]₆}(OTf) (4) compound. Comparison of their antimicrobial activity with selected lead(II) and bismuth(III) analogs and free ligands showed that only bismuth(III) complexes demonstrated significant antimicrobial activity, from two- to fivefold larger than the free ligands. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

Review

Jump to: Research

16 pages, 2986 KiB

Open AccessReview

Metalloporphyrin Metal–Organic Frameworks: Eminent Synthetic Strategies and Recent Practical Exploitations

by Arash Ebrahimi and Lukáš Krivosudský

Molecules 2022, 27(15), 4917; https://doi.org/10.3390/molecules27154917 - 2 Aug 2022

Cited by 9 | Viewed by 5659

Abstract

The emergence of metal–organic frameworks (MOFs) in recent years has stimulated the interest of scientists working in this area as one of the most applicable archetypes of three-dimensional structures that can be used as promising materials in several applications including but not limited [...] Read more.

The emergence of metal–organic frameworks (MOFs) in recent years has stimulated the interest of scientists working in this area as one of the most applicable archetypes of three-dimensional structures that can be used as promising materials in several applications including but not limited to (photo-)catalysis, sensing, separation, adsorption, biological and electrochemical efficiencies and so on. Not only do MOFs have their own specific versatile structures, tunable cavities, and remarkably high surface areas, but they also present many alternative procedures to overcome emerging obstacles. Since the discovery of such highly effective materials, they have been employed for multiple uses; additionally, the efforts towards the synthesis of MOFs with specific properties based on planned (template) synthesis have led to the construction of several promising types of MOFs possessing large biological or bioinspired ligands. Specifically, metalloporphyrin-based MOFs have been created where the porphyrin moieties are either incorporated as struts within the framework to form porphyrinic MOFs or encapsulated inside the cavities to construct porphyrin@MOFs which can combine the peerless properties of porphyrins and porous MOFs simultaneously. In this context, the main aim of this review was to highlight their structure, characteristics, and some of their prominent present-day applications. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

15 pages, 2646 KiB

Open AccessReview

Metal Complexes or Chelators with ROS Regulation Capacity: Promising Candidates for Cancer Treatment

by Xiang Li, Yuhui Wang, Man Li, Huipeng Wang and Xiongwei Dong

Molecules 2022, 27(1), 148; https://doi.org/10.3390/molecules27010148 - 27 Dec 2021

Cited by 28 | Viewed by 4323

Abstract

Reactive oxygen species (ROS) are rapidly eliminated and reproduced in organisms, and they always play important roles in various biological functions and abnormal pathological processes. Evaluated ROS have frequently been observed in various cancers to activate multiple pro-tumorigenic signaling pathways and induce the [...] Read more.

Reactive oxygen species (ROS) are rapidly eliminated and reproduced in organisms, and they always play important roles in various biological functions and abnormal pathological processes. Evaluated ROS have frequently been observed in various cancers to activate multiple pro-tumorigenic signaling pathways and induce the survival and proliferation of cancer cells. Hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−) are the most important redox signaling agents in cancer cells, the homeostasis of which is maintained by dozens of growth factors, cytokines, and antioxidant enzymes. Therefore, antioxidant enzymes tend to have higher activity levels to maintain the homeostasis of ROS in cancer cells. Effective intervention in the ROS homeostasis of cancer cells by chelating agents or metal complexes has already developed into an important anti-cancer strategy. We can inhibit the activity of antioxidant enzymes using chelators or metal complexes; on the other hand, we can also use metal complexes to directly regulate the level of ROS in cancer cells via mitochondria. In this review, metal complexes or chelators with ROS regulation capacity and with anti-cancer applications are collectively and comprehensively analyzed, which is beneficial for the development of the next generation of inorganic anti-cancer drugs based on ROS regulation. We expect that this review will provide a new perspective to develop novel inorganic reagents for killing cancer cells and, further, as candidates or clinical drugs. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Crystal Structure of Coordination Compounds)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Synthesis, Characterization and Crystal Structure of Coordination Compounds

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Related Special Issue

Published Papers (12 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI