Vibrational spectra of 3-phenylpropionic acid and L-phenylalanine

Castro, José L.; Ramírez, María Rosa López; Arenas, Juan F.; Otero, Juan C.

doi:10.1016/j.molstruc.2004.10.098

Cited by 15 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figure , hydrocinnamic acid, sodium hydrocinnamate, and the HCA-Na-HCA cocrystal product exhibited significant differences in the fingerprint region of their infrared absorption spectra. Using the ab initio study of the vibrational modes of the hydrocinnamate (i.e., the 3-phenylpropionate) ion in conjunction with the authoritative sources − and analogy to the phenylacetate studies, assignments for the observed absorption bands of three species were deduced. These are provided in Table .…”

Section: Resultsmentioning

confidence: 99%

Vibrational Spectroscopic Studies of Cocrystals and Salts. 3. Cocrystal Products Formed by Benzenecarboxylic Acids and Their Sodium Salts

Brittain¹

2010

Crystal Growth & Design

View full text Add to dashboard Cite

X-ray powder diffraction, differential scanning calorimetry, infrared absorption spectroscopy, and Raman spectroscopy have been used to study the phenomenon of salt formation in four benzenecarboxylic acids (benzoic acid, phenylacetic acid, hydrocinnamic acid, and 4-phenylbutanoic acid), and in the 1:1 stoichiometric products formed by the cocrystallization of a free acid and a sodium salt. Assignments were derived for the observed peaks in both infrared absorption and Raman spectra of the reactants and their products. In all instances, it was observed that the energy of the antisymmetric stretching mode of the carbonyl group of the free benzenecarboxylic acid invariably shifted to higher energies when that acid formed a cocrystal with a sodium salt of another benzenecarboxylic acid. In addition, the symmetric stretching mode of the benzenecarboxylic acid carbonyl group disappeared in the Raman spectrum of its sodium salt and was also absent in the Raman spectrum of the cocrystal product. It was also found that the antisymmetric carboxylate anion stretching mode, the symmetric carboxylate anion stretching mode, the out-of-plane carboxylate deformation mode, and the vibrational modes associated with the phenyl ring and alkane side chains were not useful spectroscopic tools to differentiate cocrystal and sodium salt, as the observed differences of these vibrational modes did not exhibit significantly consistent differences between the various forms.

show abstract

Section: Resultsmentioning

confidence: 99%

Vibrational Spectroscopic Studies of Cocrystals and Salts. 3. Cocrystal Products Formed by Benzenecarboxylic Acids and Their Sodium Salts

Brittain¹

2010

Crystal Growth & Design

View full text Add to dashboard Cite

show abstract

“…In order to have a reliable assignment of the vibrational spectrum of Bz − , the B3LYP/6-31+G* force field of the ground state has been scaled following the quantum mechanical force field (SQMFF) methodology of Pulay et al , The scale factors corresponding to internal coordinates of the same character were kept identical, as done in previous works. , The selected set of independent internal coordinates and their respective fitted scale factors are submitted as Supporting Information (Figure S1 and Table S1).…”

Section: Resultsmentioning

confidence: 99%

Surface-Enhanced Raman Scattering of Benzoate Anion Adsorbed on Silver Nanoclusters: Evidence of the Transient Formation of the Radical Dianion

et al. 2010

View full text Add to dashboard Cite

Surface-enhanced Raman scattering (SERS) of benzoate recorded on silver electrode have been analyzed on the basis of a charge transfer (CT) enhancement mechanism similar to a resonance Raman (RR) process where a photoinduced electron transfer between a metal and an adsorbate takes place. Given that benzoic acid (BzH) is adsorbed on silver as benzoate anion (Bz -), this resonant CT process implies the transient formation of the corresponding radical dianion (Bz •2-). The dependence of the relative SERS intensities on the electrode potential has been analyzed on the basis of ab initio calculations of the electronic properties of the isolated adsorbate in its ground and excited CT states (Bz -and Bz •2-, respectively). Moreover, configuration interaction singles (CIS) calculations have also been carried out for the Ag 2 -benzoate (Ag 2 -Bz -) supermolecule, which shows two excited singlets, namely CT 0 ; 1 B 1 and CT 1 ; 1 A 2 , where the properties of the adsorbate are quite similar to those of the radical dianion of the isolated species. The theoretical calculations predict the selective enhancement of modes 8a and ν s (CO 2 -) under CT resonant conditions in close agreement with the SERS results. This confirms once again the relevance of resonant CT processes in the SERS of aromatic molecules and the usefulness of this technique in the study of very unstable species such as radical anions or dianions of aromatic adsorbates.

show abstract

“…This is the frequency of bending mode (deformation vibration) of the bonds CH 2 /CH 3 that occurs in phospholipids and proteins, such as collagen. Alongside with this band, other bands are also confidently recorded, namely, the band at 1210 cm 1 (stretching vibrations C-C 6 H 5 in tryptophan and phenylalanine), 1230 cm -1 (stretching asymmetric vibrations of PO 2 -in nucleic acids), 1265 cm -1 (stretching vibrations of CN, bending vibrations of NH in amid III, α-spirals, collagen, and tryptophan), 1300 cm -1 (twisting and wagging CH 2 vibrations in collagen and phospholipids), 1335 cm -1 (wagging vibrations of CH 3 CH 2 in collagen and nucleic acids), 1520, 1550, 1580 cm -1 (stretching vibrations C=C in carotenoids, tryptophan and porphyrin, and phenylalanine, respectively), 1620 cm -1 (stretching vibrations C=C in tryptophan and porphyrin), 1660 cm -1 (stretching vibrations C=O in amid I, α-spirals and proteins, such as collagen and elastin, stretching vibrations С=С in fats), 1700, 1750 and 1780 cm -1 (stretching vibrations С=О in phospholipids) [5,[14][15][16][17].…”

Section: Analysis Of Raman Spectra Of Lung Neoplasmsmentioning

confidence: 99%

Lung neoplasm diagnostics using Raman spectroscopy and autofluorescence analysis

Artemyev

Zakharov

Bratchenko

et al. 2015

JBPE

View full text Add to dashboard Cite

Abstract. A method of lung neoplasm diagnostics is proposed based on the combined analysis of Raman and autofluorescence spectra excited by laser beam with the wavelength 785 nm. Such approach allows fast selection of the pathology region followed by differentiation of the neoplasm type. The developed method demonstrated the sensitivity of 90.9% and the specificity of 71.4% in the differentiation of squamous cell carcinoma and adenocarcinoma cases. © 2015 Samara State Aerospace University (SSAU).

show abstract

Vibrational spectra of 3-phenylpropionic acid and L-phenylalanine

Cited by 15 publications

References 5 publications

Vibrational Spectroscopic Studies of Cocrystals and Salts. 3. Cocrystal Products Formed by Benzenecarboxylic Acids and Their Sodium Salts

Vibrational Spectroscopic Studies of Cocrystals and Salts. 3. Cocrystal Products Formed by Benzenecarboxylic Acids and Their Sodium Salts

Surface-Enhanced Raman Scattering of Benzoate Anion Adsorbed on Silver Nanoclusters: Evidence of the Transient Formation of the Radical Dianion

Lung neoplasm diagnostics using Raman spectroscopy and autofluorescence analysis

Contact Info

Product

Resources

About