Materials

Research

9 pages, 2057 KiB

Open AccessArticle

From Isostructurality to Structural Diversity of Ag(I) Coordination Complexes Formed with Imidazole Based Bipodal Ligands, and Disclosure of a Unique Topology

by Liliana Dobrzańska

Materials 2022, 15(5), 1852; https://doi.org/10.3390/ma15051852 - 1 Mar 2022

Cited by 1 | Viewed by 1837

Abstract

Two Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)benzene (bib) and counterions BF₄^¯(1) and PF₆^¯ (2) were synthesized in order to check their behavior in forming molecular/crystal structures. This allows comparison with the final products of [...] Read more.

Two Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)benzene (bib) and counterions BF₄^¯(1) and PF₆^¯ (2) were synthesized in order to check their behavior in forming molecular/crystal structures. This allows comparison with the final products of analogous syntheses performed with similar bidentate ligands containing methyl substituents on the benzene ring, namely 1,3-bis(imidazol-1-ylmethyl)-5-methylbenzene (bimb) and 1,3-bis(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (bitmb). The Ag(I) complexes obtained with the methylated ligands mentioned above form isostructural pairs of waved 1D chains or dinuclear boxes, of general formula {[Ag(bimb)]X}_n and [Ag₂(btmb)₂]X₂, respectively (X = BF₄^¯, PF₆^¯), under the same reaction conditions. SCXRD analyses of 1 and 2 revealed the formation of polymeric coordination compounds of formula {[Ag₂(bib)₃](BF₄)₂}_n and {[Ag(bib)]PF₆}_n, respectively, different from those observed for bimb. The 3D coordination polymer 1 forms a unique 5,5-c net of 5,5T188 topological type, observed for the very first time for a coordination compound, with silver cations adopting a trigonal geometry, whereas 2 shows the presence of 1D single-stranded cationic helices with linear coordination of the metal centers. Interestingly, these complexes differ not only from the mentioned isostructural pairs of related Ag(I) complexes, but also from the isostructural pair of compounds obtained as the final product when reacting bib and bimb with the larger counterion CF₃SO₃^¯. Hirshfeld surface analyses indicate a higher contribution of F···H intermolecular contacts in 2 than in 1, with H^…H contacts being dominant in the latter. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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13 pages, 3593 KiB

Open AccessArticle

Structural Characterization of Multicomponent Crystals Formed from Diclofenac and Acridines

by Artur Mirocki and Artur Sikorski

Materials 2022, 15(4), 1518; https://doi.org/10.3390/ma15041518 - 17 Feb 2022

Cited by 4 | Viewed by 2502

Abstract

Multicomponent crystals containing diclofenac and acridine (1) and diclofenac and 6,9-diamino-2-ethoxyacridine (2) were synthesized and structurally characterized. The single-crystal XRD measurements showed that compound 1 crystallizes in the triclinic P-1 space group as a salt cocrystal with one [...] Read more.

Multicomponent crystals containing diclofenac and acridine (1) and diclofenac and 6,9-diamino-2-ethoxyacridine (2) were synthesized and structurally characterized. The single-crystal XRD measurements showed that compound 1 crystallizes in the triclinic P-1 space group as a salt cocrystal with one acridinium cation, one diclofenac anion, and one diclofenac molecule in the asymmetric unit, whereas compound 2 crystallizes in the triclinic P-1 space group as an ethanol solvate monohydrate salt with one 6,9-diamino-2-ethoxyacridinium cation, one diclofenac anion, one ethanol molecule, and one water molecule in the asymmetric unit. In the crystals of the title compounds, diclofenac and acridines ions and solvent molecules interact via N–H⋯O, O–H⋯O, and C–H⋯O hydrogen bonds, as well as C–H⋯π and π–π interactions, and form heterotetramer bis[⋯cation⋯anion⋯] (1) or heterohexamer bis[⋯cation⋯ethanol⋯anion⋯] (2). Moreover, in the crystal of compound 1, acridine cations and diclofenac anions interact via N–H⋯O hydrogen bond, C–H⋯π and π–π interactions to produce blocks, while diclofenac molecules interact via C–Cl⋯π interactions to form columns. In the crystal of compound 2, the ethacridine cations interact via C–H⋯π and π–π interactions building blocks, while diclofenac anions interact via π–π interactions to form columns. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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19 pages, 8222 KiB

Open AccessArticle

Relationship between the Crystal Structure and Tuberculostatic Activity of Some 2-Amidinothiosemicarbazone Derivatives of Pyridine

by Katarzyna Gobis, Małgorzata Szczesio, Andrzej Olczak, Tomasz Pawlak, Ewa Augustynowicz-Kopeć, Malwina Krause and Marek L. Główka

Materials 2022, 15(1), 349; https://doi.org/10.3390/ma15010349 - 4 Jan 2022

Cited by 1 | Viewed by 1729

Abstract

Tuberculosis remains one of the most common diseases affecting developing countries due to difficult living conditions, the rapidly increasing resistance of M. tuberculosis strains and the small number of effective anti-tuberculosis drugs. This study concerns the relationship between molecular structure observed in a [...] Read more.

Tuberculosis remains one of the most common diseases affecting developing countries due to difficult living conditions, the rapidly increasing resistance of M. tuberculosis strains and the small number of effective anti-tuberculosis drugs. This study concerns the relationship between molecular structure observed in a solid-state by X-ray diffraction and the ¹⁵N NMR of a group of pyridine derivatives, from which promising activity against M. tuberculosis was reported earlier. It was found that the compounds exist in two tautomeric forms: neutral and zwitterionic. The latter form forced the molecules to adopt a stable, unique, flat frame due to conjugation and the intramolecular hydrogen bond system. As the compounds exist in a zwitterionic form in the crystal state generally showing higher activity against tuberculosis, it may indicate that this geometry of molecules is the “active” form. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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15 pages, 4928 KiB

Open AccessArticle

Single-Crystal X-ray and Solid-State NMR Characterisation of AND-1184 and Its Hydrochloride Form

by Tomasz Pawlak, Małgorzata Szczesio and Marek J. Potrzebowski

Materials 2021, 14(23), 7175; https://doi.org/10.3390/ma14237175 - 25 Nov 2021

Cited by 1 | Viewed by 1724

Abstract

In this study, we report on a structural investigation of AND-1184, with the chemical name N-[3-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]propyl]-3-methylbenzenesulfonamide (MBS), and its hydrochloride form (MBS^HCl); AND-1184 is a potential API for the treatment of dementia. The single-crystal X-ray investigation of both [...] Read more.

In this study, we report on a structural investigation of AND-1184, with the chemical name N-[3-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]propyl]-3-methylbenzenesulfonamide (MBS), and its hydrochloride form (MBS^HCl); AND-1184 is a potential API for the treatment of dementia. The single-crystal X-ray investigation of both forms results in monoclinic crystal systems with P2₁/c and C2/c symmetry for MBS and MBS^HCl, respectively. This solid-state NMR study, combined with quantum-chemical calculations, allowed us to assign all ¹³C and most ¹H signals. The MBS structure was defined as a completely rigid system without significant dynamic behaviours, whereas MBS^HCl exhibited limited dynamic motion of the aromatic part of the molecule. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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17 pages, 9631 KiB

Open AccessArticle

Structures 4-n-propyl Piperazines as Non-Imidazole Histamine H3 Antagonists

by Andrzej Olczak, Jarosław Sukiennik, Beata Olszewska, Monika Stefaniak, Krzysztof Walczyński and Małgorzata Szczesio

Materials 2021, 14(22), 7094; https://doi.org/10.3390/ma14227094 - 22 Nov 2021

Viewed by 1622

Abstract

Seven new low-temperature structures of 4-n-propylpiperazine derivatives, potential H3 receptor antagonists, have been determined by X-ray crystallography, with the following symmetry and unit cell parameters: 2-(4-propyl-piperazin-1-yl)oxazolo[4,5-c]pyridine (compound 1), P-1, 5.9496 Å, 12.4570 Å, 12.8656 Å, 112.445°, 95.687°, 103.040°; 2-(4-propyl-piperazin-1-yl)thia-zolo[4,5-c]pyridine (compound 2), I [...] Read more.

Seven new low-temperature structures of 4-n-propylpiperazine derivatives, potential H3 receptor antagonists, have been determined by X-ray crystallography, with the following symmetry and unit cell parameters: 2-(4-propyl-piperazin-1-yl)oxazolo[4,5-c]pyridine (compound 1), P-1, 5.9496 Å, 12.4570 Å, 12.8656 Å, 112.445°, 95.687°, 103.040°; 2-(4-propyl-piperazin-1-yl)thia-zolo[4,5-c]pyridine (compound 2), I2/a, 22.2087 Å, 7.5519 Å, 19.9225 Å, β = 92.368°; 2-(4-propyl-piperazin-1-yl)oxazolo[5,4-c]pyridine (compound 3), C2/c, 51.1351 Å, 9.36026 Å, 7.19352 Å, β = 93.882°; 2-(4-propyl-piperazin-1-yl)thiazolo[5,4-c]pyridine (compound 4), Pbcn, 19.2189 Å, 20.6172 Å, 7.4439 Å; 2-(4-propylpiperazin-1-yl)[1,3]oxazolo[4,5-b]pyridine, hydrate (structure 5), Pbca, 7.4967 Å, 12.2531 Å, 36.9527 Å; 2-(4-propylpiperazin-1-yl)[1,3]oxazolo[4,5-b]pyridine, first polymorph (structure 6), P-1, 7.2634 Å, 11.1261 Å, 18.5460 Å, 80.561°, 80.848°, 76.840°; 2-(4-propylpiperazin-1-yl)[1,3]oxazolo[4,5-b]pyridine, second polymorph (structure 7), P2₁, 8.10852 Å, 7.06025 Å, 12.41650 Å, β = 92.2991°. All the compounds crystallized out as hydrobromides. Oxazole structures show a much greater tendency to form twin crystals than thiazole structures. All the investigated structures display N—H···Br hydrogen bonding. (ADME) analysis, including the assessment of absorption, distribution, metabolism, and excretion, determined the physicochemical properties, pharmacokinetics, drug similarity, and bioavailability radar, and confirmed the usefulness of the compounds in question for pharmaceutical utility. This work is a continuation of the research searching for a new lead of non-imidazole histamine H3 receptor antagonists. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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13 pages, 2519 KiB

Open AccessArticle

Structure of a Fe₄O₆-Heteraadamantane-Type Hexacation Stabilized by Chelating Organophosphine Oxide Ligands

by Anna Pietrzak, Jannick Guschlbauer and Piotr Kaszyński

Materials 2021, 14(22), 6840; https://doi.org/10.3390/ma14226840 - 12 Nov 2021

Cited by 2 | Viewed by 1630

Abstract

Metal-containing heteraadamantanes are compounds of interest due to their spectroscopic and magnetic properties, which make them promising materials for non-linear optics and semiconductors. Herein we report the comprehensive structural characterization of a new coordination compound of the formula [(µ-OH′)₂( [...] Read more.

Metal-containing heteraadamantanes are compounds of interest due to their spectroscopic and magnetic properties, which make them promising materials for non-linear optics and semiconductors. Herein we report the comprehensive structural characterization of a new coordination compound of the formula [(µ-OH′)₂(µ-OH″)₄(O = P(Ph₂)CH₂CH₂(Ph₂)P = O)₄{Fe(t-BuOH)}₄](PF₆)₄(Cl)₂ with the chelating ligand Ph₂P(O)-CH₂CH₂-P(O)Ph₂. The compound crystallizes as a polynuclear metal complex with the adamantane-like core [Fe₄O₆] in the space group I-43d of a cubic system. The single-crystal XRD analysis showed that the crystal contains one symmetrically independent octahedrally coordinated Fe atom in the oxidation state +3. The adamantine-like scaffold of the Fe complex is formed by hydroxy bridging oxygen atoms only. Hirshfeld surface analysis of the bridging oxygen atoms revealed two types of µ-OH groups, which differ in the degree of exposure and participation in long-range interactions. Additionally, the Hirshfeld surface analysis supported by the enrichment ratio calculations demonstrated the high propensity of the title complex to form C-H^…Cl, C-H^…F and C-H^…O interactions. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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19 pages, 4734 KiB

Open AccessArticle

Structural Evidence of Active Site Adaptability towards Different Sized Substrates of Aromatic Amino Acid Aminotransferase from Psychrobacter Sp. B6

by Anna Bujacz, Jedrzej Rum, Maria Rutkiewicz, Agnieszka J. Pietrzyk-Brzezinska and Grzegorz Bujacz

Materials 2021, 14(12), 3351; https://doi.org/10.3390/ma14123351 - 17 Jun 2021

Cited by 7 | Viewed by 1962

Abstract

Aromatic amino acid aminotransferases present a special potential in the production of drugs and synthons, thanks to their ability to accommodate a wider range of substrates in their active site, in contrast to aliphatic amino acid aminotransferases. The mechanism of active site adjustment [...] Read more.

Aromatic amino acid aminotransferases present a special potential in the production of drugs and synthons, thanks to their ability to accommodate a wider range of substrates in their active site, in contrast to aliphatic amino acid aminotransferases. The mechanism of active site adjustment toward substrates of psychrophilic aromatic amino acid aminotransferase (PsyArAT) from Psychrobacter sp. B6 is discussed based on crystal structures of complexes with four hydroxy-analogs of substrates: phenylalanine, tyrosine, tryptophan and aspartic acid. These competitive inhibitors are bound in the active center of PsyArAT but do not undergo transamination reaction, which makes them an outstanding tool for examination of the enzyme catalytic center. The use of hydroxy-acids enabled insight into substrate binding by native PsyArAT, without mutating the catalytic lysine and modifying cofactor interactions. Thus, the binding mode of substrates and the resulting analysis of the volume of the catalytic site is close to a native condition. Observation of these inhibitors’ binding allows for explanation of the enzyme’s adaptability to process various sizes of substrates and to gain knowledge about its potential biotechnological application. Depending on the character and size of the used inhibitors, the enzyme crystallized in different space groups and showed conformational changes of the active site upon ligand binding. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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12 pages, 3391 KiB

Open AccessFeature PaperArticle

Structural, Spectroscopic, Thermal, and Magnetic Properties of a New Dinuclear Copper Coordination Compound with Tiglic Acid

by Marcin Świątkowski, Suneel Lanka, Agnieszka Czylkowska, Katarzyna Gas and Maciej Sawicki

Materials 2021, 14(9), 2148; https://doi.org/10.3390/ma14092148 - 23 Apr 2021

Cited by 11 | Viewed by 2372

Abstract

The first coordination compound of copper and tiglic acid named tetrakis(μ-tiglato)bis(tiglic acid)dicopper(II) was synthesized and crystallized from water solution. Its structure was determined and analyzed based on X-ray diffraction measurement. The paddle-wheel coordination system of the investigated compound was compared with other similar [...] Read more.

The first coordination compound of copper and tiglic acid named tetrakis(μ-tiglato)bis(tiglic acid)dicopper(II) was synthesized and crystallized from water solution. Its structure was determined and analyzed based on X-ray diffraction measurement. The paddle-wheel coordination system of the investigated compound was compared with other similar copper structures known in the literature. The Hirshfeld analysis was used for the detailed analysis of intermolecular interaction. The new compound was also characterized in terms of infrared absorption, thermal, and magnetic properties. The antiferromagnetic coupling of copper ions was found. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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9 pages, 5490 KiB

Open AccessArticle

Counterion Effect and Isostructurality in a Series of Ag(I) Complexes Containing a Flexible, Imidazole Based Dipodal Ligand

by Liliana Dobrzańska

Materials 2021, 14(7), 1804; https://doi.org/10.3390/ma14071804 - 6 Apr 2021

Cited by 3 | Viewed by 1981

Abstract

The crystal structures of a series of Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)-5-methylbenzene (L) and the counterions BF₄⁻ (1), PF₆⁻ (2), ClO₄⁻ (3), and CF₃SO₃⁻ (4 [...] Read more.

The crystal structures of a series of Ag(I) complexes with 1,3-bis(imidazol-1-ylmethyl)-5-methylbenzene (L) and the counterions BF₄⁻ (1), PF₆⁻ (2), ClO₄⁻ (3), and CF₃SO₃⁻ (4) were analysed to determine the effect of the latter on their formation. All resulting compounds crystallise in the non-centrosymmetric space group Cc of a monoclinic system and show the formation of cationic, polymeric 1D Ag(I) complexes. SCXRD analyses revealed that compounds 1–3 are isostructural, though 1 shows opposite handedness compared to 2 and 3, resulting in an inversed packing arrangement. The presence of the larger, elongated triflate counterion in 4 leads to a different ligand conformation, as well as different arrangements of the ligand in the cationic chain, and simultaneously results in a packing that exhibits fewer similarities with the remaining three compounds. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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13 pages, 15523 KiB

Open AccessArticle

The Influence of Solvent on the Crystal Packing of Ethacridinium Phthalate Solvates

by Artur Mirocki and Artur Sikorski

Materials 2020, 13(22), 5073; https://doi.org/10.3390/ma13225073 - 10 Nov 2020

Cited by 5 | Viewed by 2464

Abstract

The synthesis, structural characterization and influence of solvents on the crystal packing of solvated complexes of ethacridine with phthalic acid: 6,9-diamino-2-ethoxyacridinium phthalate methanol solvate (1), 6,9-diamino-2-ethoxyacridinium phthalate ethanol solvate (2), 6,9-diamino-2-ethoxyacridinium phthalate isobutanol solvate (3), and 6,9-diamino-2-ethoxyacridinium [...] Read more.

The synthesis, structural characterization and influence of solvents on the crystal packing of solvated complexes of ethacridine with phthalic acid: 6,9-diamino-2-ethoxyacridinium phthalate methanol solvate (1), 6,9-diamino-2-ethoxyacridinium phthalate ethanol solvate (2), 6,9-diamino-2-ethoxyacridinium phthalate isobutanol solvate (3), and 6,9-diamino-2-ethoxyacridinium phthalate tert-butanol solvate monohydrate (4) are described in this article. Single-crystal XRD measurements revealed that the compounds 1–4 crystallized in the triclinic P-1 space group, and the 6,9-diamino-2-ethoxyacridinium cations, phthalic acid anions and solvent molecules interact via strong N–H···O, O–H···O, C–H···O hydrogen bonds, and C–H···π and π–π interactions to form different types of basic structural motifs, such as: heterotetramer bis[···cation···anion···] in compound 1 and 2, heterohexamer bis[···cation···alcohol···anion···] in compound 3, and heterohexamer bis[···cation···water···anion···] in compound 4. Presence of solvents molecule(s) in the crystals causes different supramolecular synthons to be obtained and thus has an influence on the crystal packing of the compounds analyzed. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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9 pages, 1576 KiB

Open AccessArticle

Deep Red Tunability and Output Power Performances of Visible Laser Emission in a Pr:Ba(Y_1−xLu_x)₂F₈ Single Crystal

by Eugenio Damiano, Giovanni Cittadino, Alberto Di Lieto and Mauro Tonelli

Materials 2020, 13(20), 4655; https://doi.org/10.3390/ma13204655 - 19 Oct 2020

Cited by 1 | Viewed by 1977

Abstract

The demand for tunable visible laser sources with high power and high beam quality, for application ranging from metrology to remote sensing, is constantly increasing. In this work, we report on the details of crystal growth, via the Czochralski method, and laser characterization [...] Read more.

The demand for tunable visible laser sources with high power and high beam quality, for application ranging from metrology to remote sensing, is constantly increasing. In this work, we report on the details of crystal growth, via the Czochralski method, and laser characterization of a Pr-doped Ba(Y

_{1 - x}

Lu

_{x}

)

_{2}

F

_{8}

(BYLF) single crystal, which is a promising candidate for fulfilling these requirements, both in terms of tunability and high-power capabilities. We measured for the first time the laser tunability curve in the deep red region obtaining a continuous range of 17 nm. The laser emission of the three main Pr

^{3 +}

lines in the visible (orange, red, and deep red) was tested under increased pump power with respect to previous studies on this material, demonstrating output powers of more than 360 mW and no thermal rolloff, up to 1.9 W of absorbed power. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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12 pages, 4983 KiB

Open AccessArticle

Crystal Structures, Hirshfeld Surfaces, and Thermal Study of Isostructural Polymeric Ladders of La(III) and Sm(III) Coordination Compounds with 4,4’-Bipyridine and Dibromoacetates

by Agnieszka Czylkowska, Anna Pietrzak, Małgorzata Szczesio, Bartłomiej Rogalewicz and Jakub Wojciechowski

Materials 2020, 13(19), 4274; https://doi.org/10.3390/ma13194274 - 25 Sep 2020

Cited by 7 | Viewed by 2262

Abstract

Two novel mixed ligand complexes with general formula [M₂(4,4′-bpy)_1.5(CBr₂HCOO)₆(H₂O)₂]_n (where 4,4′-bpy = 4,4′-bipyridine) were synthesized. Thermal analysis was used to describe a solid intermediate and final products of thermolysis. A [...] Read more.

Two novel mixed ligand complexes with general formula [M₂(4,4′-bpy)_1.5(CBr₂HCOO)₆(H₂O)₂]_n (where 4,4′-bpy = 4,4′-bipyridine) were synthesized. Thermal analysis was used to describe a solid intermediate and final products of thermolysis. A coupled TG-MS system was used to monitor principal volatile fragments evolved during pyrolysis. Crystal structures of the complexes were determined. Cationic dinuclear M₂ (M(III) = La, Sm) coordination cores were obtained. Both crystal structures are isostructural. Single crystal X-ray diffraction analysis revealed that investigated structures of 1D coordination polymers assembled in ladder-like systems. The central atom replacement resulted in unit cell identity parameter П = 0.0091. Additionally, the isostructurality of the reported La(III) and Sm(III) complexes was revealed using Hirshfeld Surface analysis supported by Enrichment Ratio calculations. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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13 pages, 2995 KiB

Open AccessArticle

Transition Metal Complexes with Flufenamic Acid for Pharmaceutical Applications—A Novel Three-Centered Coordination Polymer of Mn(II) Flufenamate

by Michał Gacki, Karolina Kafarska, Anna Pietrzak, Małgorzata Szczesio, Izabela Korona-Głowniak and Wojciech M. Wolf

Materials 2020, 13(17), 3705; https://doi.org/10.3390/ma13173705 - 21 Aug 2020

Cited by 10 | Viewed by 2467

Abstract

Five complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with non-steroidal anti-inflammatory drug, flufenamic acid were synthesized: (1) [Mn₃(fluf)₆EtOH)(H₂O)]_·3EtOH; (2) [Co(fluf)₂(EtOH)(H₂O)]_·H₂O; (3) [Ni(fluf)₂(EtOH)(H₂O)] [...] Read more.

Five complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with non-steroidal anti-inflammatory drug, flufenamic acid were synthesized: (1) [Mn₃(fluf)₆EtOH)(H₂O)]_·3EtOH; (2) [Co(fluf)₂(EtOH)(H₂O)]_·H₂O; (3) [Ni(fluf)₂(EtOH)(H₂O)]_·H₂O; (4) [Cu(fluf)_2·H₂O]; (5) [Zn(fluf)_2·H₂O]. All complexes were characterized by elemental analysis (EA), flame atomic absorption spectrometry (FAAS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The crystal structure of 1 was determined by the single crystal X-ray diffraction technique. It crystallizes in the triclinic space group P

\bar{1}

with three independent Mn(II) cations, six coordinated flufenamato ligands augmented with water and ethanol molecules in the inner coordination sphere. In this crystal, manganese atoms are multiplied by symmetry and form infinite, polymeric chains which extend along the [001] dimension. The Hirshfeld Surface analysis revealed changes in interaction assemblies around all metal centers. The antioxidant and antimicrobial activities were established for all complexes and free ligand for comparison. All compounds exhibit good or moderate bioactivity against Gram-positive bacteria and yeasts. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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14 pages, 3381 KiB

Open AccessArticle

Precipitation and Transformation of Vaterite Calcium Carbonate in the Presence of Some Organic Solvents

by Donata Konopacka-Łyskawa, Natalia Czaplicka, Marcin Łapiński, Barbara Kościelska and Rafał Bray

Materials 2020, 13(12), 2742; https://doi.org/10.3390/ma13122742 - 17 Jun 2020

Cited by 19 | Viewed by 3659

Abstract

In this paper, the production of CaCO₃ particles via the carbonation route in the reaction of CaCl₂ and CO₂, using NH₃ as a promoter of CO₂ absorption, was studied. The solvents used as the reaction media for [...] Read more.

In this paper, the production of CaCO₃ particles via the carbonation route in the reaction of CaCl₂ and CO₂, using NH₃ as a promoter of CO₂ absorption, was studied. The solvents used as the reaction media for CaCO₃ precipitation were aqueous solutions of methanol, isopropanol and dimethyl sulfoxide (DMSO), in a concentration range of 0–20% (v/v). It was found that the presence of an organic additive influenced the precipitation rate, the content of vaterite in the obtained product, the morphology and the size of the precipitated CaCO₃ particles, as well as the rate of its transformation into calcite. The presence of all added organic solvents reduced the vaterite concentration in the produced CaCO₃ both at the end of the reaction and after incubation in the reaction medium for 1 h. However, the transformation of vaterite particles into calcite in the tested solutions was slower when the 4 h and 24 h procedures were compared. The interactions of solvents with calcite and vaterite were compared using HPLC tests. DMSO molecules interacted with vaterite particles the most strongly, while the interaction of isopropanol with this polymorph was the weakest. The opposite effect was observed for interactions with calcite particles, and the affinity decreased in the series: isopropanol, methanol, DMSO. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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20 pages, 3760 KiB

Open AccessArticle

Horsetail (Equisetum Arvense) as a Functional Filler for Natural Rubber Biocomposites

by Marcin Masłowski, Justyna Miedzianowska, Agnieszka Czylkowska and Krzysztof Strzelec

Materials 2020, 13(11), 2526; https://doi.org/10.3390/ma13112526 - 2 Jun 2020

Cited by 26 | Viewed by 4262

Abstract

Over the past decades, increased scientific and research activity has been observed in the development of new, innovative materials for various end uses. This is mainly due to the growing ecological, environmental, and material awareness of many industries and societies. Equisteum arvense-horsetail [...] Read more.

Over the past decades, increased scientific and research activity has been observed in the development of new, innovative materials for various end uses. This is mainly due to the growing ecological, environmental, and material awareness of many industries and societies. Equisteum arvense-horsetail is a plant that has demonstrated its properties in pharmacological and clinical aspects as well as in vitro and in vivo biological activity. This article presents a new method of using horsetail as a natural, lignocellulosic filler for a natural rubber matrix. In-depth characteristics of the applied bio-additive were prepared based on several research techniques and methods such as ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy with energy dispersive X-RAY spectroscopy, thermogravimetric analysis, and flame atomic absorption spectroscopy. Elastomer composites were prepared as a function of horsetail content. Then, an analysis of their main functional properties was performed, including mechanical properties and susceptibility to accelerated aging processes such as thermo-oxidative, ultraviolet radiation, and weathering. The research emphasizes the significant value of horsetail in its new role—as an active filler of elastomer biocomposites. The obtained results confirmed that horsetail is lignocellulosic material thermally stable up to 180 °C. Horsetail is an active filler to natural rubber, positively affecting mechanical strength. Due to the presence of flavonoids and phenolic acids in horsetail, it can be used as a polymer anti-aging agent. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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9 pages, 3531 KiB

Open AccessArticle

Novel Coordination Polymer of Cadmium (II) with L-Tryptophan

by Agnieszka Czylkowska, Małgorzata Szczesio, Anna Pietrzak, Anita Raducka and Bartłomiej Rogalewicz

Materials 2020, 13(10), 2266; https://doi.org/10.3390/ma13102266 - 14 May 2020

Cited by 1 | Viewed by 2365

Abstract

A new cadmium (II) polymeric coordination compound with tryptophan (Trp) of general formula {[Cd(L-Trp)₂(H₂O)Cl]∙(Trp)∙(H₂O)}_n was synthesized. The monocrystals of the investigated complex were obtained using the method of slow evaporation. The crystal and molecular [...] Read more.

A new cadmium (II) polymeric coordination compound with tryptophan (Trp) of general formula {[Cd(L-Trp)₂(H₂O)Cl]∙(Trp)∙(H₂O)}_n was synthesized. The monocrystals of the investigated complex were obtained using the method of slow evaporation. The crystal and molecular structure was determined. The compound was crystallized in the orthorhombic P2₁2₁2₁ space group. The cadmium atom was seven coordinates by two oxygen atoms from one bidentate-chelating carboxylate group of bridging Trp, two oxygen atoms from one bidentate-chelating carboxylate group from a monodentate organic ligand, one oxygen atom of water molecule, one nitrogen atom of the amino group from bridging Trp and one chlorine atom, which means that every tridentate Trp substituent was bridging towards one cadmium atom and bidentate chelating towards one another. The monodentate Trp is a zwitterionic molecule. The coordination led to the formation of 1D supramolecular chains entrapping water and Trp molecules. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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15 pages, 1389 KiB

Open AccessArticle

Thermoplastic Elastomeric Composites Filled with Lignocellulose Bioadditives, Part 2: Flammability, Thermo-Oxidative Aging Resistance, Mechanical and Barrier Properties

by Justyna Miedzianowska, Marcin Masłowski and Krzysztof Strzelec

Materials 2020, 13(7), 1608; https://doi.org/10.3390/ma13071608 - 1 Apr 2020

Cited by 3 | Viewed by 2174

Abstract

The work covers the characteristics of the functional properties of composites bordering thermoplastics and elastomers. The research is a continuation of considerations on blends in the form of a mixture of natural rubber (NR) with an ethylene–vinyl acetate copolymer (EVA) and the addition [...] Read more.

The work covers the characteristics of the functional properties of composites bordering thermoplastics and elastomers. The research is a continuation of considerations on blends in the form of a mixture of natural rubber (NR) with an ethylene–vinyl acetate copolymer (EVA) and the addition of a lignocellulose biofiller (wheat straw). After describing the processing and rheology as well as examining the thermal properties and morphology of composites (Part 1), the second part focuses on the characteristics of their performance. The effect of both different ratios of mixed polymers and the amount of filler on tensile strength and elongation at break, resistance to thermo-oxidative aging, hardness, tear resistance, barrier and damping properties, as well as flammability were investigated. The increased EVA content has shown a positive effect on tensile strength, elongation at break, resistance to thermo-oxidative aging, hardness, relative damping, tear strength, barrier and burning delay. On the other hand, a larger amount of natural rubber provides high flexibility and promotes the creation of a reinforcing structure by the filler used. Moreover, a significant impact of the addition of cereal straw on the barrier, damping, strength and flammability properties of composites was also noted. The great advantage of the prepared compositions in relation to commercial plastics is their environmental friendliness, primarily by replacing some petroleum derivatives of plastics with natural rubber and straw fibers. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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20 pages, 5861 KiB

Open AccessArticle

Thermoplastic Elastomeric Composites Filled with Lignocellulose Bioadditives. Part 1: Morphology, Processing, Thermal and Rheological Properties

by Justyna Miedzianowska, Marcin Masłowski and Krzysztof Strzelec

Materials 2020, 13(7), 1598; https://doi.org/10.3390/ma13071598 - 1 Apr 2020

Cited by 6 | Viewed by 3116

Abstract

Thermoplastic elastomer blends based on natural rubber (NR) and ethylene-vinyl acetate copolymer (EVA) with different weight ratios (30, 40, 50, 60 and 70 parts per hundred rubber (phr) of NR) and 10, 20 and 30 phr of straw were prepared and characterized. Current [...] Read more.

Thermoplastic elastomer blends based on natural rubber (NR) and ethylene-vinyl acetate copolymer (EVA) with different weight ratios (30, 40, 50, 60 and 70 parts per hundred rubber (phr) of NR) and 10, 20 and 30 phr of straw were prepared and characterized. Current environmental problems were the motivation to produce this type of system, namely: the need to replace plastics at least partly with natural materials; increasing the amount of renewable raw materials and managing excess straw production. When using this bioadditive in traditional materials, the high processing temperature can be problematic, leading to the degradation of straw fibers. The solution can be polymer mixtures that are prepared at significantly lower temperatures. Scanning electron microscope (SEM) imaging was used to investigate the particle size of fibers and phase morphology of composites. Moreover, determination of the thermal properties of the filler and composites showed that the processing temperature used in the production of NR/EVA blends reduces the risk of degradation of the natural filler. Differential scanning calorimetry (DSC) was used to determine the thermal behavior of the filled composites. Finally, rheological tests of materials allow the determination of optimal processing parameters and properties of materials in dynamic conditions. The proposed blends exhibit elastic properties, and due to the lack of chemical cross-linking they can be processed and recycled like thermoplastics. In addition, they offset the disadvantages and combine the advantages of natural rubber and ethylene-vinyl acetate copolymer in the form of thermoplastic elastomeric biocomposites. Full article

(This article belongs to the Special Issue Crystal Growth and Structure)

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