Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders
In this article, we present fluorescent guanidiniocarbonyl-indoles as versatile oxo-anion binders. Herein, the guanidiniocarbonyl-indole (GCI) and methoxy-guanidiniocarbonyl-indole (MGCI) were investigated as ethylamides and compared with the well-known guanidiniocarbonyl-pyrrole (GCP) concerning th...
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| Format: | Article |
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MDPI AG
2022-05-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/9/3005 |
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| author | Daniel Sebena Kevin Rudolph Bibhisan Roy Christoph Wölper Till Nitschke Sarah Lampe Michael Giese Jens Voskuhl |
| author_facet | Daniel Sebena Kevin Rudolph Bibhisan Roy Christoph Wölper Till Nitschke Sarah Lampe Michael Giese Jens Voskuhl |
| author_sort | Daniel Sebena |
| collection | DOAJ |
| description | In this article, we present fluorescent guanidiniocarbonyl-indoles as versatile oxo-anion binders. Herein, the guanidiniocarbonyl-indole (GCI) and methoxy-guanidiniocarbonyl-indole (MGCI) were investigated as ethylamides and compared with the well-known guanidiniocarbonyl-pyrrole (GCP) concerning their photophysical properties as well as their binding behavior towards oxo-anions. Hence, a variety of anionic species, such as carboxylates, phosphonates and sulfonates, have been studied regarding their binding properties with GCP, GCI and MGCI using UV-Vis titrations, in combination with the determination of the complex stoichiometry using the Job method. The emission properties were studied in relation to the pH value using fluorescence spectroscopy as well as the determination of the photoluminescence quantum yields (PLQY). Density functional theory (DFT) calculations were undertaken to obtain a better understanding of the ground-lying electronic properties of the investigated oxo-anion binders. Additionally, X-ray diffraction of GCP and GCI was conducted. We found that GCI and MGCI efficiently bind carboxylates, phosphonates and sulfonates in buffered aqueous solution and in a similar range as GCP (K<sub>ass</sub> ≈ 1000–18,000 M<sup>−1</sup>, in bis-tris buffer, pH = 6); thus, they could be regarded as promising emissive oxo-anion binders. They also exhibit a visible fluorescence with a sufficient PLQY. Additionally, the excitation and emission wavelength of MGCI was successfully shifted closer to the visible region of the electromagnetic spectrum by introducing a methoxy-group into the core structure, which makes them interesting for biological applications. |
| first_indexed | 2024-03-10T03:52:30Z |
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| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T03:52:30Z |
| publishDate | 2022-05-01 |
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| record_format | Article |
| series | Molecules |
| spelling | doaj.art-3c83685e8700439d81fa057dc712bed32023-11-23T08:52:54ZengMDPI AGMolecules1420-30492022-05-01279300510.3390/molecules27093005Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion BindersDaniel Sebena0Kevin Rudolph1Bibhisan Roy2Christoph Wölper3Till Nitschke4Sarah Lampe5Michael Giese6Jens Voskuhl7Faculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Inorganic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyFaculty of Chemistry (Organic Chemistry), University of Duisburg-Essen, 45117 Essen, GermanyIn this article, we present fluorescent guanidiniocarbonyl-indoles as versatile oxo-anion binders. Herein, the guanidiniocarbonyl-indole (GCI) and methoxy-guanidiniocarbonyl-indole (MGCI) were investigated as ethylamides and compared with the well-known guanidiniocarbonyl-pyrrole (GCP) concerning their photophysical properties as well as their binding behavior towards oxo-anions. Hence, a variety of anionic species, such as carboxylates, phosphonates and sulfonates, have been studied regarding their binding properties with GCP, GCI and MGCI using UV-Vis titrations, in combination with the determination of the complex stoichiometry using the Job method. The emission properties were studied in relation to the pH value using fluorescence spectroscopy as well as the determination of the photoluminescence quantum yields (PLQY). Density functional theory (DFT) calculations were undertaken to obtain a better understanding of the ground-lying electronic properties of the investigated oxo-anion binders. Additionally, X-ray diffraction of GCP and GCI was conducted. We found that GCI and MGCI efficiently bind carboxylates, phosphonates and sulfonates in buffered aqueous solution and in a similar range as GCP (K<sub>ass</sub> ≈ 1000–18,000 M<sup>−1</sup>, in bis-tris buffer, pH = 6); thus, they could be regarded as promising emissive oxo-anion binders. They also exhibit a visible fluorescence with a sufficient PLQY. Additionally, the excitation and emission wavelength of MGCI was successfully shifted closer to the visible region of the electromagnetic spectrum by introducing a methoxy-group into the core structure, which makes them interesting for biological applications.https://www.mdpi.com/1420-3049/27/9/3005oxo-anion bindersmolecular recognitionfluorescencesupramolecular chemistry |
| spellingShingle | Daniel Sebena Kevin Rudolph Bibhisan Roy Christoph Wölper Till Nitschke Sarah Lampe Michael Giese Jens Voskuhl Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders Molecules oxo-anion binders molecular recognition fluorescence supramolecular chemistry |
| title | Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders |
| title_full | Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders |
| title_fullStr | Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders |
| title_full_unstemmed | Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders |
| title_short | Evolution of Artificial Arginine Analogues—Fluorescent Guanidiniocarbonyl-Indoles as Efficient Oxo-Anion Binders |
| title_sort | evolution of artificial arginine analogues fluorescent guanidiniocarbonyl indoles as efficient oxo anion binders |
| topic | oxo-anion binders molecular recognition fluorescence supramolecular chemistry |
| url | https://www.mdpi.com/1420-3049/27/9/3005 |
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