Density functional and experimental studies on the FT‐IR and FT‐Raman spectra and structure of benzoic acid and 3,5‐dichloro salicylic acid

Krishnakumar, V.; Mathammal, R.

doi:10.1002/jrs.2118

Cited by 31 publications

(23 citation statements)

References 16 publications

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“…This initiator is split by UV light into a benzoyl radical and an alkyl radical and one of the possible reaction end products is benzoic acid [24]. Benzoic acid Raman peaks that match closely to those observed at 15 min crosslinking are at 618 cm -1 , 708 cm -1 , 1035 cm -1 and 1165 cm -1 [25] and the Raman peaks at 1003 cm -1 and 1600 cm -1 are attributed to C=C aromatic ring stretching from other biproducts of the benzoyl radical. The reaction end products from the benzoyl radical are yellow and those from the alkyl radical generally evaporate during the polymerization process.…”

Section: (A)mentioning

confidence: 59%

Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Bäckström¹,

Benavente²,

Berg³

et al. 2012

MSA

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Hydrogels are highly water-absorbent hydrophilic polymer networks, which show potential in many biocompatible applications. In previous work, we demonstrated the feasibility of using poly(ethylene glycol) dimethacrylate (PEG-DMA) gels polymerized with a photoinitiator for encapsulation and stabilization of painted biomimetic membrane arrays for novel separation technologies or biosensor applications. These gels were formed from PEG-DMA monomers suspended in phosphate buffered saline (PBS) solution and gelated by radical polymerization in the presence of the photoinitiator Darocur 1173. In this work, we show that the properties of a PEG-DMA hydrogel formed by photoinitiated polymerizetion can be tailored by varying the photocrosslinking time. Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy (RS) showed that the optimal crosslinking time for the gel was 6 -10 minutes and that the water content of the gels could be tuned in the range of 50 -90 wt%. The resistivity was between 0.8 -3.5 Ωm, which is comparable to that of PBS. The low resistivity of the gel makes it compatible for encapsulating membranes for (ion channel based) biosensor applications. With FTIR and RS we identified spectral features of the hydrogel, which may serve as a diagnostic tool to monitor changes in the gels due to variation in parameters such as time, pH, temperature, aging or exposure to chemicals or biological material.

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Section: (A)mentioning

confidence: 59%

Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Bäckström¹,

Benavente²,

Berg³

et al. 2012

MSA

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“…To study the vibrational characteristics and structural parameters of 5-(4-methoxyphenyl)-2-methylthio-5,12-dihydrobenzo[g]pyrimido [4,5-b]quinoline-4,6,11(3H)-trione 4c, we performed a theoretical study at DFT level, which allows us to set the geometric and energetic parameters of the title compound. The optimized structure with B3LYP/6-31G(d,p) level is shown in Figure 2 [46][47][48][49][50]. The calculated geometric parameter (bond lengths, bond angles and dihedral angles) at same levels of calculation for title compound was compared with the experimental parameters, see Table 3, showing very good correlation.…”

Section: Theoretical Calculationsmentioning

confidence: 90%

Computational and Experimental Study on Molecular Structure of Benzo[g]pyrimido[4,5-b]quinoline Derivatives: Preference of Linear over the Angular Isomer

et al. 2017

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A series of 5-aryl-2-methylthio-5,12-dihydrobenzo[g]pyrimido [4,5-b]quinoline-4,6,11(3H) -trione was synthesized through an environmental friendly multicomponent methodology and characterized with FT-IR (Fourier Transform infrared spectroscopy), 1 H NMR (Nuclear Magnetic Resonance ), 13 C NMR and GC-MS (gas chromatography-mass spectrometry). The 5-(4-methoxyphenyl)-2-methylthio-5,12-dihydrobenzo[g]pyrimido [4,5-b]quinoline-4,6,11(3H)-trione 4c compound was characterized by X-ray single crystal diffraction. The geometry of 4c has been fully optimized using DFT (Density functional theory), B3LYP functional and 6-31G(d,p) basis set, thus establishing the ground state energy and thermodynamic features for the mentioned compound, which are in accordance with the experimental data and the crystal structure. The experimental results reveal a strong preference for the regioselective formation of 4c linear four fused rings over the angular four fused and suggest a possible kinetic control in product formation.

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“…For salicylic acid, the O-H vibration is observed to 3238 cm −1 in FT-IR spectra. [10] Krishnakumar and Mathammal [42] observed the O-H stretching vibration at 3500 cm −1 for 3,5-dichloro salicylic acid. This band for 5-BrSA is observed at 3551 and 3250 cm −1 and also calculated at 3610 and 3334 cm −1 .…”

Section: Geometrical Structuresmentioning

confidence: 99%

“…In view of this, the band in FT-IR at 651 cm −1 having a very strong Raman counterpart at 649 cm −1 is assigned to the C-Cl stretching of 5-ClSA. Krishnakumar and Mathammal [42] observed in Raman spectrum at 850 and 749 cm −1 was assigned to the C-Cl stretching mode of 3,5-dichloro salicylic acid. The wavenumber 631 cm −1 is observed with strong infrared and Raman intensities is assigned to C-Cl stretching mode by Shanker et al [56] According to the calculated TED, our calculations show that there is no pure C-X band vibration.…”

Section: Geometrical Structuresmentioning

confidence: 99%

“…This is in agreement with the literature. [42,49,54] An assignment of the C-F stretching modes is very difficult as these modes are strongly coupled with the other in-plane modes. Normally, the intensity of the C-F stretching vibrations is very strong in the IR spectra and these appear in the range 1000-1300 cm −1 as assigned earlier.…”

Section: Geometrical Structuresmentioning

confidence: 99%

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FT‐Raman, FT‐IR spectra and DFT calculations on monomeric and dimeric structures of 5‐fluoro‐ and 5‐chloro‐salicylic acid

Karabacak¹,

Kose²,

Kurt³

2010

J Raman Spectroscopy

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The experimental and theoretical study on the structures and vibrations of 5-fluoro-salicylic acid and 5-chloro-salicylic acid (5-FSA and 5-ClSA, C 7 H 5 FO 3 and C 7 H 5 ClO 3 ) is presented. The Fourier transform infrared spectra (4000-400 cm −1 ) and the Fourier transform Raman spectra (4000-50 cm −1 ) of the title molecules in the solid phase were recorded. The molecular structures, vibrational wavenumbers, infrared intensities, Raman intensities and Raman scattering activities were calculated for a pair of molecules linked by the intermolecular O-H· · ·O hydrogen bond. The geometrical parameters and energies of 5-FSA and 5ClSA were obtained for all eight conformers/isomers from density functional theory (DFT) (B3LYP) with 6-311++G(d,p) basis set calculations. The computational results identified the most stable conformer of 5-FSA and 5-ClSA as the C1 form. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method. The spectroscopic and theoretical results were compared with the corresponding properties for 5-FSA and 5-ClSA monomers and dimer of C1 conformer. The optimized bond lengths, bond angles and calculated wavenumbers showed the best agreement with the experimental results.

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Density functional and experimental studies on the FT‐IR and FT‐Raman spectra and structure of benzoic acid and 3,5‐dichloro salicylic acid

Cited by 31 publications

References 16 publications

Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Tailoring Properties of Biocompatible PEG-DMA Hydrogels with UV Light

Computational and Experimental Study on Molecular Structure of Benzo[g]pyrimido[4,5-b]quinoline Derivatives: Preference of Linear over the Angular Isomer

FT‐Raman, FT‐IR spectra and DFT calculations on monomeric and dimeric structures of 5‐fluoro‐ and 5‐chloro‐salicylic acid

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