Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub>
Supramolecular chemistry has become a central theme in chemical and biological sciences over the last decades. Supramolecular structures are being increasingly used in biomedical applications, particularly in devices requiring specific stimuli-responsiveness. Fullerenes, and supramolecular assemblie...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/26/16/5000 |
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| author | Patrícia D. Barata Alexandra I. Costa Sérgio Costa José V. Prata |
| author_facet | Patrícia D. Barata Alexandra I. Costa Sérgio Costa José V. Prata |
| author_sort | Patrícia D. Barata |
| collection | DOAJ |
| description | Supramolecular chemistry has become a central theme in chemical and biological sciences over the last decades. Supramolecular structures are being increasingly used in biomedical applications, particularly in devices requiring specific stimuli-responsiveness. Fullerenes, and supramolecular assemblies thereof, have gained great visibility in biomedical sciences and engineering. Sensitive and selective methods are required for the study of their inclusion in complexes in various application fields. With this in mind, two new fluorescent bis-calix[4]arene-carbazole conjugates (<b>4</b> and <b>5</b>) have been designed. Herein, their synthesis and ability to behave as specific hosts for fullerenes C<sub>60</sub> and C<sub>70</sub> is described. The optical properties of the novel compounds and their complexes with C<sub>60</sub> and C<sub>70</sub> were thoroughly studied by UV-Vis and steady-state and time-resolved fluorescence spectroscopies. The association constants (<i>K</i><sub>a</sub>) for the complexation of C<sub>60</sub> and C<sub>70</sub> by <b>4</b> and <b>5</b> were determined by fluorescence techniques. A higher stability was found for the C<sub>70</sub>@<b>4</b> supramolecule (<i>K</i><sub>a</sub> = 5.6 × 10<sup>4</sup> M<sup>−1</sup>; Δ<i>G</i> = −6.48 kcal/mol). Evidence for the formation of true inclusion complexes between the host <b>4</b> and C<sub>60</sub>/C<sub>70</sub> was obtained from NMR spectroscopy performed at low temperatures. The experimental findings were fully corroborated by density functional theory (DFT) models performed on the host–guest assemblies (C<sub>60</sub>@<b>4</b> and C<sub>70</sub>@<b>4</b>). |
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| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-10T08:33:15Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-808e4b2200ad485b8112b7913aaaa0412023-11-22T08:55:17ZengMDPI AGMolecules1420-30492021-08-012616500010.3390/molecules26165000Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub>Patrícia D. Barata0Alexandra I. Costa1Sérgio Costa2José V. Prata3Departamento de Engenharia Química, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, PortugalDepartamento de Engenharia Química, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, PortugalDepartamento de Engenharia Química, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, PortugalDepartamento de Engenharia Química, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro, 1, 1959-007 Lisboa, PortugalSupramolecular chemistry has become a central theme in chemical and biological sciences over the last decades. Supramolecular structures are being increasingly used in biomedical applications, particularly in devices requiring specific stimuli-responsiveness. Fullerenes, and supramolecular assemblies thereof, have gained great visibility in biomedical sciences and engineering. Sensitive and selective methods are required for the study of their inclusion in complexes in various application fields. With this in mind, two new fluorescent bis-calix[4]arene-carbazole conjugates (<b>4</b> and <b>5</b>) have been designed. Herein, their synthesis and ability to behave as specific hosts for fullerenes C<sub>60</sub> and C<sub>70</sub> is described. The optical properties of the novel compounds and their complexes with C<sub>60</sub> and C<sub>70</sub> were thoroughly studied by UV-Vis and steady-state and time-resolved fluorescence spectroscopies. The association constants (<i>K</i><sub>a</sub>) for the complexation of C<sub>60</sub> and C<sub>70</sub> by <b>4</b> and <b>5</b> were determined by fluorescence techniques. A higher stability was found for the C<sub>70</sub>@<b>4</b> supramolecule (<i>K</i><sub>a</sub> = 5.6 × 10<sup>4</sup> M<sup>−1</sup>; Δ<i>G</i> = −6.48 kcal/mol). Evidence for the formation of true inclusion complexes between the host <b>4</b> and C<sub>60</sub>/C<sub>70</sub> was obtained from NMR spectroscopy performed at low temperatures. The experimental findings were fully corroborated by density functional theory (DFT) models performed on the host–guest assemblies (C<sub>60</sub>@<b>4</b> and C<sub>70</sub>@<b>4</b>).https://www.mdpi.com/1420-3049/26/16/5000calix[4]arenecarbazolefluorescencefullerenesupramolecularhost–guest chemistry |
| spellingShingle | Patrícia D. Barata Alexandra I. Costa Sérgio Costa José V. Prata Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> Molecules calix[4]arene carbazole fluorescence fullerene supramolecular host–guest chemistry |
| title | Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> |
| title_full | Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> |
| title_fullStr | Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> |
| title_full_unstemmed | Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> |
| title_short | Fluorescent Bis-Calix[4]arene-Carbazole Conjugates: Synthesis and Inclusion Complexation Studies with Fullerenes C<sub>60</sub> and C<sub>70</sub> |
| title_sort | fluorescent bis calix 4 arene carbazole conjugates synthesis and inclusion complexation studies with fullerenes c sub 60 sub and c sub 70 sub |
| topic | calix[4]arene carbazole fluorescence fullerene supramolecular host–guest chemistry |
| url | https://www.mdpi.com/1420-3049/26/16/5000 |
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