Aminobenzonitrile adsorption on silver nanoparticles (SNPs) was studied with SERS, SEIRA, and DFT. It was found that 4-aminobenzonitrile (4ABN) and 2-aminobenzonitirle (2ABN) could resonantly distribute an amino group charge so that the cyano group could strongly interact with the SNPs in the mono/multilayer. Cyano stretching frequency shifts in SEIRA spectra showed that a 4ABN multilayer interacted strongly with the SNPs when deposited using an alkane solvent with nonpolar bonds. 2ABN could interact with the SNPs even when deposition occurred using a solvent with polar bonds because intramolecular hydrogen-bonding in 2ABN limited solvation. 3-Aminobenzonitrile (3ABN) never interacted strongly with the SNPs in the multilayer because it could not resonantly distribute the amino group charge. 2ABN also formed C−H hydrogen-bonds with n-heptane, which could interact with both the amino and cyano groups of 2ABN. Charge transfer between adsorbed ABN isomers and the SNPs is evidenced in SERS spectra by the presence of nontotally symmetric vibrational bands that do not appear intense in Raman spectra of the ABN powders. It is anticipated that this work will affect applications where interactions of benzonitrile compounds with metal nanoparticles is important.

A combination of surface-enhanced infrared absorption (SEIRA) and density functional theory (DFT) was used to study the adsorption of the dihydroxybenzene (DH) isomers on silver nanostructures (SNSs). No evidence was observed for the oxidation of any of the DH isomers during adsorption on SNSs. It was found that the SNSs weakened intermolecular hydrogen bonding in thin DH layers adsorbed on SNSs versus the bulk powders with the effect being more pronounced for para-dihydroxybenzene (PDH) than ortho-dihydroxybenzene (ODH) and meta-dihydroxybenzene (MDH). DFT simulations of the infrared spectra of ODH and MDH dimers were good reproductions of the SEIRA spectra and infrared spectra of ODH/MDH powder, but DFT dimer infrared simulations were less effective at modeling the PDH results due to the large variations of hydrogen bonding between PDH films formed on SNSs versus PDH powder. Hydrogen-bonding effects were observed between acetone and both PDH and ODH in thin layers adsorbed on SNSs, and C−H•••O hydrogen bonding was also seen between n-heptane and PDH and ODH in adsorption experiments on SNSs. These hydrogen-bonding effects were not detected between MDH and either acetone or n-heptane due to differences in resonance effects between MDH versus ODH and PDH.

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