Journal article
Elucidation of pH impacts on monosubstituted benzene derivatives using normal Raman and surface-enhanced Raman scattering
The Journal of chemical physics, Vol.153(18), pp.184707-184707
11/14/2020
DOI: 10.1063/5.0029445
PMCID: PMC7863684
PMID: 33187422
Abstract
Raman spectral vibrational frequencies are used to probe the local chemical environment surrounding molecules in solution and adsorbed to gold nanostars. Herein, the impacts of functional group protonation on monosubstituted benzene derivatives with amine, carboxylic acid, or hydroxide are evaluated. Changes in binding affinity and orientation are apparent by evaluating systematic variations in vibrational frequencies. Notably, the electron donating abilities of these functional groups influence the vibrational frequency of the ring breathing mode, thus leading to improved spectral interpretation. Furthermore, gold nanostars are used to investigate the impact of molecular protonation on the adsorption of benzoic acid/benzoate to gold. The changes in molecular protonation are measured using zeta potential and the surface-sensitive technique, surface-enhanced Raman scattering. These methods reveal that pH variations induce carboxylate protonation and electron redistribution that weaken molecular affinity, thereby causing the molecule to adopt a perpendicular to parallel orientation with respect to the nanostar surface. Functional group identity influences the ring breathing mode frequency as a function of changes in electron donation from the functional group to the ring in solution as well as molecular affinity to and orientation on gold. This exploitation of vibrational frequencies facilitates the elucidation of molecule behavior in complex systems.
Details
- Title: Subtitle
- Elucidation of pH impacts on monosubstituted benzene derivatives using normal Raman and surface-enhanced Raman scattering
- Creators
- Wenjing Xi - Chemistry Department, University of Iowa, Iowa City, Iowa 52242, USAAmanda J Haes - Chemistry Department, University of Iowa, Iowa City, Iowa 52242, USA
- Resource Type
- Journal article
- Publication Details
- The Journal of chemical physics, Vol.153(18), pp.184707-184707
- DOI
- 10.1063/5.0029445
- PMID
- 33187422
- PMCID
- PMC7863684
- ISSN
- 0021-9606
- eISSN
- 1089-7690
- Grant note
- P30 ES005605 / NIEHS NIH HHS
- Language
- English
- Date published
- 11/14/2020
- Academic Unit
- Hygienic Laboratory - Rec; Chemistry
- Record Identifier
- 9984216600902771
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