Multifaceted adsorption of α-cyano-4-hydroxycinnamic acid on silver colloidal and island surfaces

Promoting Intra- and Intermolecular Interactions in Surface-Enhanced Raman Scattering

“…This vibrational frequency is consistent with the molecules interacting with the metal via σ interactions or perpendicular binding geometries. Similarly, the vibrational modes associated with carboxylic acid (in acidic conditions) and carboxylate groups (in basic conditions) also exhibit pH and orientation-dependent SERS spectral features . The carboxylate stretching mode only appears in basic conditions while vibrational modes representing the protonated structure are not observed in acidic solutions .…”

“…Because CN stretches are Raman active and exhibit unique vibrational frequencies, resulting Raman spectra can be used to understand surface coordination. Basic solutions promoted the parallel adsorption of CN to the surface . This was demonstrated by evaluating the vibrational frequency of the CN stretch mode.…”

“…Chemisorption is caused by strong perturbations of molecular electronic structure during chemical bond formation with a substrate , and is less influenced by the local environment compared to physisorption . Molecules containing functional groups that chemisorb to SERS substrates include thiol, − pyridine, amine, nitrile, and carboxylic acid and promote SERS detection because of strong and direct binding affinity to the metal surface. Furthermore, these molecules are able to replace stabilizing reagents and ions.…”

Intramolecular charge transfer of a push–pull chromophore with restricted internal rotation of an electron donor

“…Notably, the split appearances of ν CN,antisym and ν CN,sym modes appear to be a sensitive measure for the changes in the molecular geometry, including the symmetry with the dicyanomethylene group. 18,82,83 The very weak ν CN,sym mode of DCM appearing only in the S 1 /CT spectrum also supports the symmetry changes with the ICT, where the twisted dimethylamino group of DCM may result in much more minor changes in the molecular symmetry compared to the twisted julolidine group of LD688. Gaffney and co-workers investigated the ICT dynamics of 9-(2,2-dicyanovinyl)julolidine by time-resolved infrared spectroscopy, where the excited-state infrared modes of ν CN,antisym and ν CN,sym were observed at 2115 and 2155 cm −1 , respectively.…”

Rapid Surface-Enhanced Raman Spectroscopy Detection of Chlorothalonil in Standard Solution and Orange Peels with Pretreatment of Ultraviolet Irradiation

“…Cyangroup is an indispensable reactive group, which plays a considerable role in the hydrophilic-lipophilic balance, electron transport, and activity of compounds among pesticides. Molecules with triple bonds are sensitive to surface properties and changes in the surrounding environment, mainly due to the variation of the triple bond's stretching vibration frequency (Jung et al 2017). Th subtle changes would be reflected on the intensity of the peak or the wavenumber in the spectrum, hence, such molecules or ions can be used as probe molecules on the surface of the study (Zhang et al 2017).…”