التفاصيل البيبلوغرافية
| العنوان: |
Absorption Spectra and the Electronic Structure of Gallic Acid in Water at Different pH: Experimental Data and Theoretical Cluster Models. |
| المؤلفون: |
Karimova NV; Department of Chemistry, University of California Irvine, Irvine, California 92697, United States., Luo M; Department of Chemistry and Biochemistry, University of California San Diego, San Diego, California 92093, United States., Sit I; Department of Nanoengineering, University of California San Diego, San Diego, California 92093, United States., Grassian VH; Department of Chemistry and Biochemistry, University of California San Diego, San Diego, California 92093, United States., Gerber RB; Department of Chemistry, University of California Irvine, Irvine, California 92697, United States.; Institute of Chemistry and Fritz Haber Research Center, Hebrew University of Jerusalem, Jerusalem 91904, Israel. |
| المصدر: |
The journal of physical chemistry. A [J Phys Chem A] 2022 Jan 20; Vol. 126 (2), pp. 190-197. Date of Electronic Publication: 2022 Jan 06. |
| نوع المنشور: |
Journal Article |
| اللغة: |
English |
| بيانات الدورية: |
Publisher: American Chemical Society Country of Publication: United States NLM ID: 9890903 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1520-5215 (Electronic) Linking ISSN: 10895639 NLM ISO Abbreviation: J Phys Chem A Subsets: PubMed not MEDLINE; MEDLINE |
| أسماء مطبوعة: |
Original Publication: Washington, D.C. : American Chemical Society, c1997- |
| مستخلص: |
Gallic acid (GA) has been characterized in terms of its optical properties in aqueous solutions at varying pH in experiments and in theoretical calculations by analyzing the protonated and deprotonated forms of GA. This work is part of a series of studies of the optical properties of different carboxylic acids in aqueous media. The experimental electronic spectra of GA exhibit two strong well-separated absorption peaks (B- and C-bands), which agree with previous studies. However, in the current study, an additional well-defined low-energy shoulder band (A-band) in the optical spectra of GA was identified. It is likely that the A-band occurs for other carboxylic acids in solution, but because it can overlap with the B-band, it is difficult to discern. The theoretical calculations based on density functional theory were used to simulate the optical absorption spectra of GA in water at different pH to prove the existence of this newly found shoulder band and to describe and characterize the full experimental optical spectra of GA. Different cluster models were tested: (i) all water molecules are coordinated near the carboxy-group and (ii) additional water molecules near the hydroxy-groups of the phenyl ring were included. In this study, we found that both the polarizable continuum model (dielectric property of a medium) and neighboring water molecules (hydrogen-bonding) play significant roles in the optical spectrum. The results showed that only an extended cluster model with water molecules near carboxy- and hydroxy-groups together with the polarizable continuum model allowed us to fully reproduce the experimental data and capture all three absorption bands (A, B, and C). The oscillator strengths of the absorption bands were obtained from the experimental data and compared with theoretical results. Additionally, our work provides a detailed interpretation of the pH effects observed in the experimental absorption spectra. |
| تواريخ الأحداث: |
Date Created: 20220106 Latest Revision: 20220120 |
| رمز التحديث: |
20231215 |
| DOI: |
10.1021/acs.jpca.1c07333 |
| PMID: |
34990547 |
| قاعدة البيانات: |
MEDLINE |
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