Thermodynamic and Spectroscopic Study of Pyrrolidine. II. Vibrational Spectra and Configuration

Evans, J. C.; Wahr, J. C.

doi:10.1063/1.1730442

Cited by 48 publications

(31 citation statements)

References 15 publications

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“…The most prominent ringstretching mode is the symmetrical ring-breathing mode, which usually appears as an intense band at 902 cm 1 in pyrrolidine. 37 In LPT, this mode is identified as a strong Raman band at 907 cm 1 and as a medium band at 904 cm 1 in the IR spectrum. It is interesting to note that this mode is split in LPT by 17 cm 1 with different intensities, at 907 and 890 cm 1 in Raman spectrum, while only the high wavenumber band appears in IR spectrum.…”

Section: Prolinium Cation Group Vibrations Pyrrolidine Ring Vibrationsmentioning

confidence: 98%

Vibrational spectral studies and the non‐linear optical properties of a novel NLO material L‐prolinium tartrate

Padmaja¹,

Vijayakumar²,

Joe³

et al. 2006

J Raman Spectroscopy

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Vibrational spectral analysis of the novel non-linear optical (NLO) material, L-prolinium tartrate (LPT) was carried out using NIR-FT-Raman and FT-IR spectroscopy. The density functional theoretical (DFT) computations have been performed at B3LYP/6-31G (d) level to derive equilibrium geometry, vibrational wavenumbers, intensities and first hyperpolarizability. The reasonable NLO efficiency, predicted for the first time in this novel compound, has been confirmed by Kurtz-Perry powder second-harmonic generation (SHG) experiments. The charge-transfer interaction between the pyrrolidine ring and the carbonyl group of the tartrate anion through the intramolecular ionic hydrogen bonds is confirmed by the simultaneous activation of ring modes in IR and Raman spectra. The splitting of the ring-breathing mode, pseudorotational ring puckering modes and the NH 2 modes of the pyrrolidine ring lead to the conclusion that the pyrrolidine ring adopts a conformation intermediate between the envelope (bent) form and the half-chair (twisted) form, resulting in the lowering of symmetry fromC 2 to C s . The lowering of the methylenic stretching wavenumbers and the enhancement of the stretching intensities suggest the existence of the electronic effects of back-donation in LPT. The positional disorder of the pyrrolidine ring, the presence of blue-shifting H-bonds as well as other non-bonded interactions in LPT, low frequency H-bond vibrations and the role of intramolecular charge transfer and the hydrogen bonds in making the molecule NLO active have been analysed on the basis of the vibrational spectral features.

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Section: Prolinium Cation Group Vibrations Pyrrolidine Ring Vibrationsmentioning

confidence: 98%

Vibrational spectral studies and the non‐linear optical properties of a novel NLO material L‐prolinium tartrate

Padmaja¹,

Vijayakumar²,

Joe³

et al. 2006

J Raman Spectroscopy

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“…One of the in-plane modes that could be readily assigned is the symmetrical ring breathing mode which appears as an intense Raman band at 902 cm 1 in pyrrolidine. 6 The L-proline ring breathing vibration is located at 902, 905 and 904 cm 1 for the cation, dipolar ion, and anion forms, respectively. 26 In the present study this ring breathing mode is found in the Raman spectra of each compound at ¾900 cm 1 as a strong band.…”

Section: Vibrations Of Pyrrolidine Ringmentioning

confidence: 99%

“…4 Normal coordinate analysis and vibrational assignment have been performed for 2-pyrrolidinones 5 having a fivemembered ring similar to that of proline. Evans and Wahr 6 have made extensive Raman spectral studies on vapor, liquid and solid forms of pyrrolidine and assigned wave numbers for various group vibrations of the ring. Raman and IR studies have been used to differentiate proline and hydroxyproline in their different salt forms.…”

Section: Introductionmentioning

confidence: 99%

FT-IR and FT-Raman spectral studies of bis(L-proline) hydrogen nitrate and bis(L-proline) hydrogen perchlorate

Pandiarajan¹,

Umadevi²,

Sasirekha³

et al. 2005

J. Raman Spectrosc.

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FT-IR and FT-Raman spectra were recorded for bis(L-proline) hydrogen nitrate and bis(L-proline) hydrogen perchlorate crystals. The wavenumber assignments have been made for the proline functional groups, viz. COOH, COO − , C-N-C-C-C ring, -[NH 2 ] + , -(CH 2 )-, C-C-N and C-H. In both crystals, two proline residues share one proton and become monoprotonated. The observed bands show that in both compounds one of the proline residues is in the zwitterionic form while the other is in the cationic form. In the two compounds under investigation, the vibrational bands for the proline residues are almost similar. In the pyrrolidine ring there exists a protonated imino group [NH 2 ] + and CH 2 groups showing the aliphatic nature of the proline in the inorganic acid environments. The symmetry of the nitrate group is not affected. Hydrogen-bonding network leads to the shifting of bands corresponding to several stretching and deformation modes. In bis(L-proline) hydrogen perchlorate, the identification of bands due to ClO 2 group reveals that the symmetry of ClO 4 − anion is possibly reduced to C 2v .

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“…We further investigated the temperature dependence of this reaction ranging from 298-413 K over both surfaces, but the rate of formation of pyrrolidine was not enhanced with temperature, and at elevated temperatures reaction deactivation was observed. pyrrolidine, 36 and butylamine 37,38 in the spectral region between 2700 and 3600 cm -1 . that an intact aromatic ring is adsorbed on the surface.…”

Section: Sample Preparationmentioning

confidence: 99%

In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

Kliewer¹

2009

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found that the ring-cracking product butylamine is a reaction poison over both surfaces studied.Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity.Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran.Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt (100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation.The hydrogenation of the α,β-unsaturated aldehydes acrolein, crotonaldehyde, and prenal were investigated over Pt(111) and Pt(100). The selectivity for the hydrogenation of the C=C bond was found to depend on the number of methyl groups added to the bond. The adsorption modes of the three aldehydes were determined. The hydrogenation of crotonaldehyde was found to be nearly structure insensitive as the TOF and selectivity were very close to the same over Pt(111) and Pt(100). SFG-VS indicated identical surface intermediates over the two crystal faces during crotonaldehyde hydrogenation.

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Thermodynamic and Spectroscopic Study of Pyrrolidine. II. Vibrational Spectra and Configuration

Cited by 48 publications

References 15 publications

Vibrational spectral studies and the non‐linear optical properties of a novel NLO material L‐prolinium tartrate

Vibrational spectral studies and the non‐linear optical properties of a novel NLO material L‐prolinium tartrate

FT-IR and FT-Raman spectral studies of bis(L-proline) hydrogen nitrate and bis(L-proline) hydrogen perchlorate

In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

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