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Soliman AIA, Sayed M, Elshanawany MM, Younis O, Ahmed M, Kamal El-Dean AM, Abdel-Wahab AMA, Wachtveitl J, Braun M, Fatehi P, Tolba MS. Base-Free Synthesis and Photophysical Properties of New Schiff Bases Containing Indole Moiety. ACS OMEGA 2022; 7:10178-10186. [PMID: 35382296 PMCID: PMC8973100 DOI: 10.1021/acsomega.1c06636] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/17/2022] [Indexed: 05/04/2023]
Abstract
Schiff bases represent an essential class in organic chemistry with antitumor, antiviral, antifungal, and antibacterial activities. The synthesis of Schiff bases requires the presence of an organic base as a catalyst such as piperidine. Base-free synthesis of organic compounds using a heterogeneous catalyst has recently attracted more interest due to the facile procedure, high yield, and reusability of the used catalyst. Herein, we present a comparative study to synthesize new Schiff bases containing indole moieties using piperidine as an organic base catalyst and Au@TiO2 as a heterogeneous catalyst. In both methods, the products were isolated in high yields and fully characterized using different spectral analysis techniques. The catalyst was reusable four times, and the activity was slightly decreased. The presence of Au increases the number of acidic sites of TiO2, resulting in C=O polarization. Yields of the prepared Schiff bases in the presence of Au@TiO2 and piperidine were comparable. However, Au@TiO2 is an easily separable and recyclable catalyst, which would facilitate the synthesis of organic compounds without applying any hazardous materials. Furthermore, the luminescence behavior of the synthesized Schiff bases exhibited spectral shape dependence on the substituent group. Interestingly, the compounds also displayed deep-blue fluorescence with Commission Internationale de l'Éclairage (CIE) coordinates of y < 0.1. Thus, these materials may contribute to decreasing the energy consumption of the emitting devices.
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Affiliation(s)
- Ahmed I. A. Soliman
- Chemistry
Department, Faculty of Science, Assiut University, Assiut 71516, Egypt
- Chemical
Engineering Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Mostafa Sayed
- Chemistry
Department, Faculty of Science, New Valley
University, El-Kharga 72511, Egypt
- Hefei
National Laboratory for Physical Sciences at the Microscale, Department
of Chemistry, University of Science and
Technology of China, Tai Hu Road, Hefei 230026, China
| | - Mahmoud M. Elshanawany
- Institute
of Physical and Theoretical Chemistry, Goethe
University, 60438 Frankfurt am Main, Germany
| | - Osama Younis
- Chemistry
Department, Faculty of Science, New Valley
University, El-Kharga 72511, Egypt
| | - Mostafa Ahmed
- Chemistry
Department, Faculty of Science, New Valley
University, El-Kharga 72511, Egypt
| | | | | | - Josef Wachtveitl
- Institute
of Physical and Theoretical Chemistry, Goethe
University, 60438 Frankfurt am Main, Germany
| | - Markus Braun
- Institute
of Physical and Theoretical Chemistry, Goethe
University, 60438 Frankfurt am Main, Germany
| | - Pedram Fatehi
- Chemical
Engineering Department, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1, Canada
| | - Mahmoud S. Tolba
- Chemistry
Department, Faculty of Science, New Valley
University, El-Kharga 72511, Egypt
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