Study of the anomalous NO2 symmetric stretch in p-NO2 aniline

Bertrán, José Fernández; Hernández, Miriam Mesa; Serna, Boris La

doi:10.1016/0584-8539(82)80190-6

Cited by 8 publications

(8 citation statements)

References 6 publications

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“…The most significant modes of 1,3,5-TNB are those assigned to symmetric (1364 and 1348 cm −1 ) and asymmetric (1544 cm −1 ) NO 2 vibrations, symmetric CN stretching mode observed to 1187 cm −1 , ring breathing mode at 1006 cm −1 , and NO 2 symmetric deformation mode observed at 828 cm −1 . It is possible to observe two different NO 2 symmetric stretching vibrations for this compound, which has been previously reported for disubstituted nitroaromatics in solution [31,32]. Epstein et al [31] have suggested that coupling of a vibrational mode of the NO 2 group with a ring vibration with CN contribution is responsible for the lower wavenumber location band.…”

Section: Resultssupporting

confidence: 73%

Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection

Fierro-Mercado

Hernández‐Rivera

2012

International Journal of Spectroscopy

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We report on a novel and extremely low-cost surface-enhanced Raman spectroscopy (SERS) substrate fabricated depositing gold nanoparticles on common lab filter paper using thermal inkjet technology. The paper-based substrate combines all advantages of other plasmonic structures fabricated by more elaborate techniques with the dynamic flexibility given by the inherent nature of the paper for an efficient sample collection, robustness, and stability. We describe the fabrication, characterization, and SERS activity of our substrate using 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, and 1,3,5-trinitrobenzene as analytes. The paper-based SERS substrates presented a high sensitivity and excellent reproducibility for analytes employed, demonstrating a direct application in forensic science and homeland security.

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Section: Resultssupporting

confidence: 73%

Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection

Fierro-Mercado

Hernández‐Rivera

2012

International Journal of Spectroscopy

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“…The band at 1320 cm -1 is assigned to the NO 2 symmetric stretch. As shown for p -nitroaniline the details of this band are complicated, since it represents a doublet band with coupling of the NO 2 mode to other vibrations . As outlined in more detail below the precise shape of this band is very sensitive to the environment of the molecule, i.e., the polarity of the surrounding medium .…”

Section: Resultsmentioning

confidence: 98%

Structural Investigation of a Self-Assembled Monolayer of a p-Nitroanilino-Terminated Thiol

et al. 1996

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Monolayers of an end-group-modified thiol, 4-(12-mercaptododecyl)aminonitrobenzene (p-NO2-C6H4-NH(CH2)12SH) formed by self-assembly on Au substrates, were investigated by grazing-incidence reflection absorption infrared spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), and contact angle measurements. The monolayer exhibits a packing of the alkyl chains which is 10-20% less dense compared to a monolayer of docosanethiol. The orientation of the aromatic end group was determined completely by a combination of IRRAS and NEXAFS. The 1,4-axis of the benzene ring is inclined to 52°with respect to the surface normal, and the plane of the benzene ring is rotated by 58°away from the plane defined by the 1,4-axis and the surface normal. No hydrogen bonding between the p-nitroaniline moieties is detected. The hydrocarbon chains do not show a preferred orientation. The film is described by a layered structure consisting of a layer of alkane chains with a high degree of gauche conformation beneath an oriented layer of the nitroaniline. Shifts of the vibrations of the alkane chain and the nitroaniline group in opposite directions are observed upon change of the temperature. This can be explained by a balance of contributions from the layer of the nitroaniline groups and the layer of the alkane chains to the total free enthalpy of the monolayer.

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“…Dinitrobenzene and dinitroaniline derivatives exhibit rather complex vibrational signatures, which depend on the vibrational coupling between the two nitro groups,57, 58 on the mesomeric effects of the substituents,59 and on the intermolecular interactions 60. 61 Indeed, precise assignment of the vibrational signals to molecular motions requires accurate calculations of the vibrational activities of molecular models that closely reproduce the polar head of the lipid DNP.…”

Section: Resultsmentioning

confidence: 99%

Vibrational Sum‐Frequency Generation Activity of a 2,4‐Dinitrophenyl Phospholipid Hybrid Bilayer: Retrieving Orientational Parameters from a DFT Analysis of Experimental Data

et al. 2013

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The vibrational nonlinear activity of films of 2,4-dinitrophenyl phospholipid (DNP) at the solid interface is measured by sum-frequency generation spectroscopy (SFG). Hybrid bilayers are formed by a Langmuir-Schaefer approach in which the lipid layer is physisorbed on top of a self-assembled monolayer of dodecanethiol on Pt with the polar heads pointing out from the surface. The SFG response is investigated in two vibrational frequency domains, namely, 3050-2750 and 1375-1240 cm(-1). The first region probes the CH stretching modes of DNP films, and the latter explores the vibrational nonlinear activity of the 2,4-dinitroaniline moiety of the polar head of the lipid. Analysis of the CH stretching vibrations suggests substantial conformational order of the aliphatic chains with only a few gauche defects. To reliably assign the detected SFG signals to specific molecular vibrations, DFT calculations of the IR and Raman activities of molecular models are performed and compared to experimental solid-state spectra. This allows unambiguous assignment of the observed SFG vibrations to molecular modes localized on the 2,4-dinitroaniline moiety of the polar head of DNP. Then, SFG spectra of DNP in the 1375-1240 cm(-1) frequency range are simulated and compared with experimental ones, and thus the 1,4-axis of the 2,4-dinitrophenyl head is estimated to have tilt and rotation angles of 45±5° and 0±30°, respectively.

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Study of the anomalous NO2 symmetric stretch in p-NO2 aniline

Cited by 8 publications

References 6 publications

Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection

Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection

Structural Investigation of a Self-Assembled Monolayer of a p-Nitroanilino-Terminated Thiol

Vibrational Sum‐Frequency Generation Activity of a 2,4‐Dinitrophenyl Phospholipid Hybrid Bilayer: Retrieving Orientational Parameters from a DFT Analysis of Experimental Data

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