Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II)
Six new coordination compounds of copper cations and 1,4-dicarboxylic acids have been synthesized and structurally investigated. Aspartic acid (H<sub>2</sub>asp), enantiopure, racemic and <i>meso</i> tartaric acid (H<sub>2</sub>tart), di-<i>para</i>-to...
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MDPI AG
2020-06-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/6/485 |
| _version_ | 1827715514305085440 |
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| author | Marius Kremer Jan van Leusen Ulli Englert |
| author_facet | Marius Kremer Jan van Leusen Ulli Englert |
| author_sort | Marius Kremer |
| collection | DOAJ |
| description | Six new coordination compounds of copper cations and 1,4-dicarboxylic acids have been synthesized and structurally investigated. Aspartic acid (H<sub>2</sub>asp), enantiopure, racemic and <i>meso</i> tartaric acid (H<sub>2</sub>tart), di-<i>para</i>-toluyltartaric acid (H<sub>2</sub>dptta) and dibenzoyltartaric acid (H<sub>2</sub>dbta) represent environmentally benign water-soluble proligands which may be deprotonated for oxygen coordination. Chelating ligands such as tetramethylethylenediamine (TMEDA) and 2-aminomethylpyridine (AMPY) efficiently reduce the dimensionality of the target compounds, and additional aqua ligands complete the coordination environments. In this line of argument, the discrete mononuclear complexes [Cu(AMPY)(asp)(H<sub>2</sub>O)] and [Cu(Hdbta)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>] were obtained; for the latter, only a preliminary structure model can be presented which, however, agrees with the powder diffraction pattern of the bulk. From enantiopure and racemic tartaric acid and TMEDA the closely related chain polymers [Cu<sup>II</sup>(H<sub>2</sub>tart)(TMEDA)(H<sub>2</sub>O)<sub>2</sub>)]<sub><i>n</i></sub> were obtained; the racemic compound consists of individual homochiral strands of opposite chirality. The high steric demand of di-<i>para</i>-toluyltartaric acid leads to one-dimensional [Cu(dptta)(EtOH)(H<sub>2</sub>O)<sub>2</sub>]<sub><i>n</i></sub> with coordinated ethanol (EtOH) in the distant Jahn–Teller site of the coordination sphere. Cu(II), <i>meso</i>-tartaric acid and TMEDA aggregate to a trinuclear coordination compound [Cu<sup>II</sup><sub>2</sub>Cu<sup>I</sup>(H<sub>2</sub>tart)(Htart)(TMEDA)<sub>2</sub>]. Its peripheral cations show the expected Jahn–Teller geometry of Cu(II), but the unambiguous assignment of the oxidation state +I for central cation required susceptibility measurements: their results prove the presence of only two and only very weakly interacting divalent cations, separated by a diamagnetic center. |
| first_indexed | 2024-03-10T19:20:03Z |
| format | Article |
| id | doaj.art-9552a541d0c84caea8b16e0ae2736684 |
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| language | English |
| last_indexed | 2024-03-10T19:20:03Z |
| publishDate | 2020-06-01 |
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| spelling | doaj.art-9552a541d0c84caea8b16e0ae27366842023-11-20T03:03:19ZengMDPI AGCrystals2073-43522020-06-0110648510.3390/cryst10060485Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II)Marius Kremer0Jan van Leusen1Ulli Englert2Institute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, GermanyInstitute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, GermanyInstitute of Inorganic Chemistry, RWTH Aachen University, 52074 Aachen, GermanySix new coordination compounds of copper cations and 1,4-dicarboxylic acids have been synthesized and structurally investigated. Aspartic acid (H<sub>2</sub>asp), enantiopure, racemic and <i>meso</i> tartaric acid (H<sub>2</sub>tart), di-<i>para</i>-toluyltartaric acid (H<sub>2</sub>dptta) and dibenzoyltartaric acid (H<sub>2</sub>dbta) represent environmentally benign water-soluble proligands which may be deprotonated for oxygen coordination. Chelating ligands such as tetramethylethylenediamine (TMEDA) and 2-aminomethylpyridine (AMPY) efficiently reduce the dimensionality of the target compounds, and additional aqua ligands complete the coordination environments. In this line of argument, the discrete mononuclear complexes [Cu(AMPY)(asp)(H<sub>2</sub>O)] and [Cu(Hdbta)<sub>2</sub>(H<sub>2</sub>O)<sub>4</sub>] were obtained; for the latter, only a preliminary structure model can be presented which, however, agrees with the powder diffraction pattern of the bulk. From enantiopure and racemic tartaric acid and TMEDA the closely related chain polymers [Cu<sup>II</sup>(H<sub>2</sub>tart)(TMEDA)(H<sub>2</sub>O)<sub>2</sub>)]<sub><i>n</i></sub> were obtained; the racemic compound consists of individual homochiral strands of opposite chirality. The high steric demand of di-<i>para</i>-toluyltartaric acid leads to one-dimensional [Cu(dptta)(EtOH)(H<sub>2</sub>O)<sub>2</sub>]<sub><i>n</i></sub> with coordinated ethanol (EtOH) in the distant Jahn–Teller site of the coordination sphere. Cu(II), <i>meso</i>-tartaric acid and TMEDA aggregate to a trinuclear coordination compound [Cu<sup>II</sup><sub>2</sub>Cu<sup>I</sup>(H<sub>2</sub>tart)(Htart)(TMEDA)<sub>2</sub>]. Its peripheral cations show the expected Jahn–Teller geometry of Cu(II), but the unambiguous assignment of the oxidation state +I for central cation required susceptibility measurements: their results prove the presence of only two and only very weakly interacting divalent cations, separated by a diamagnetic center.https://www.mdpi.com/2073-4352/10/6/485coordination compoundslow toxicitychiralityblocking ligandsmagnetochemistrysingle crystal diffraction |
| spellingShingle | Marius Kremer Jan van Leusen Ulli Englert Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) Crystals coordination compounds low toxicity chirality blocking ligands magnetochemistry single crystal diffraction |
| title | Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) |
| title_full | Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) |
| title_fullStr | Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) |
| title_full_unstemmed | Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) |
| title_short | Coordination Compounds Featuring Non-Toxic Chiral 1,4-Dicarboxylic Acids and Copper(II) |
| title_sort | coordination compounds featuring non toxic chiral 1 4 dicarboxylic acids and copper ii |
| topic | coordination compounds low toxicity chirality blocking ligands magnetochemistry single crystal diffraction |
| url | https://www.mdpi.com/2073-4352/10/6/485 |
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