Influence of Substituent Type and Position on the Adsorption Mechanism of Phenylboronic Acids: Infrared, Raman, and Surface-Enhanced Raman Spectroscopy Studies

Abstract

This paper shows systematic spectroscopic studies using Fourier-transform infrared absorption (FT-IR), Fourier-transform Raman (FT-Raman), and surface-enhanced Raman (SERS) in an aqueous silver sol of fluoro and formyl analogues of phenylboronic acids: 2-fluorophenylboronic acid (2-F-PhB(OH)2), 3-fluorophenylboronic acid (3-F-PhB(OH)2), 4-fluorophenylboronic acid (4-F-PhB(OH)2), 2-formylphenylboronic acid (2-CHO-PhB(OH)2), 3-formylphenylboronic acid (3-CHO-PhB(OH)2), and 4-formylphenylboronic acid (4-CHO-PhB(OH)2). To produce an extensive table of vibrational spectra, density functional theory (DFT) calculations with the B3LYP method at the 6-311++G(d,p) level of theory were performed for the ground state geometry of the most stable species, dimers in cis-trans conformation. On the basis of the SERS spectral profile, the adsorption modes of the phenylboronic acid isomers were proposed. The type of substituent and its position in the phenyl ring have a strong influence on the geometry of isomers on the silver nanoparticle's surface. This effect was especially evident in the case of 4-CH-PhB(OH)2, for which dearomatization of the phenyl ring took place upon adsorption.

Solid state formulations composed by amphiphilic polymers for delivery of proteins: characterization and stability

“…5 and the major peak assignments detailed in Table S3. The spectra obtained were in close agreement with others already reported (Thakral et al, 2012;Guo et al, 1999;Piergies et al, 2013;Vanea and Simon, 2013). In the spectrum of insulin, characteristic peaks related to amide I (1659 and 1673 cm À1 ) and the aromatic rings of phenylalanine (1005 and 1606-1612 cm À1 ) and tyrosine (832 cm À1 ) can be identified.…”

Highly selective and sensitive surface enhanced Raman scattering nanosensors for detection of hydrogen peroxide in living cells

“…1B), meaning that 4-CA molecules were successfully functionalized on Au NPs by amide bonds since SERS is a surface selective technique and Au NPs have been washed with ultrapure water. In the SERS spectrum, the strong Raman bands at 821, 1011, 1031, 1178, 1270, 1562 cm À 1 (Table S1) (Piergies et al, 2013;Alver and Parlak, 2010;Kong et al, 2013). It also can be seen from Fig.…”

Thin Layer Chromatography Coupled with Surface-Enhanced Raman Scattering as a Facile Method for On-Site Quantitative Monitoring of Chemical Reactions

“…Considering the roughness of the TLC plate surface, 11 spectra of each sample spot were collected and the average value was adopted to calculate the SERS signal intensity. Figure 2A shows the SERS intensity of 999 cm −1 Raman band, the strongest breathing mode (ν 12 ) of phenyl ring, 24 at a series of phenylboronic acid concentrations, indicating that 42-nm AuNPs showed the best performance.…”