Wyniki wyszukiwania - BazTech

1

Zastosowanie spektroskopii oscylacyjnej w detekcji barwników azowych w opakowaniach do żywności

Kucharska Edyta, Michalski Jacek, Sąsiadek Wojciech, Dymińska Lucyna, Hołubniak Paulina, Hanuza Jerzy

Wiadomości Chemiczne

|

2023

|

[Z] 77, 7-8

687--718

EN

This work is a continuation of our research on spectroscopic and structural properties and applications of a number of azo-dipyridine and phenyl-azopyridine derivatives. In the previous works, the results of DFT quantum calculations were used to discuss infrared and Raman spectra. The presented study generalizes these results using the literature data on the structure of aromatic azo compounds. Analysis of the spectra and detailed assignment of the observed bands to the specific oscillating modes enables their application to identification of azo dyes widely used in the food industry. The bioactivity of azo dyes means that the safety of their use requires the search for new methods of their detection in food. The paper shows that vibrational spectroscopy is an effective diagnostic method for identifying not only the material from which the plastic foil is made, but also the dye used for its dyeing. In this work, the method was applied to colour plastic foils used as pasta packaging. It has been shown that this foil is made of polypropylene, and azo dyes, such as orange yellow (orange dye), tartrazine (yellow dye), allura red (red dye), brilliant blue (blue dye) and a mixture of yellow and blue dyes (green dye) were used for its dyeing.

2

Optimized geometry, vibration (IR and Raman) spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

Tamer O., Atalay A. S., Avci D., Atalay Y., Tarcan E., Marchewka M. K.

Materials Science Poland

|

2016

|

Vol. 34, No. 1

192--203

EN

The molecular modeling of p-nitroanilinium perchlorate molecule was carried out by using B3LYP and HSEH1PBE levels of density functional theory (DFT). The IR and Raman spectra were simulated and the assignments of vibrational modes were performed on the basis of relative contribution of various internal co-ordinates. NBO analysis was performed to demonstrate charge transfer, conjugative interactions and the formation of intramolecular hydrogen bonding interactions within PNAPC. Obtained large dipole moment values showed that PNAPC is a highly polarizable complex, and the charge transfer occurs within PNAPC. Hydrogen bonding and charge transfer interactions were also displayed by small HOMO-LUMO gap and molecular electrostatic potential (MEP) surface. The strong evidences that the material can be used as an efficient nonlinear optical (NLO) material of PNAPC were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.

3

Vibrational Study of the Structural Phase Transitions in a New Ferroelastic (C5H10NH2)SbCl6 Crystal by Infrared and Raman Spectroscopies

Bednarska-Bolek B., Jakubas R., Bator G., Baran J.

Polish Journal of Chemistry

|

2002

|

Vol. 76 / nr 2-3

385-394

EN

Infrared spectra of (C5H10NH2)SbCl6 in the region of the internal vibrations of the piperidinium cations (3500-400 cm-1) and Raman spectra in the region of internal vibrations of the SbCl6 _ anions (400-100 cm-1), around the phase transitions at Tc3 = 294 K, Tc2 = 310 K and Tc1 = 369 K, are presented and discussed. A detailed analysis has been performed for the bands assigned to the stretching and deformation vibrations of the NH2 _ and CH2 groups. It has been shown that the hydrogen bonds play an important role in the mechanism of the phase transitions and influence the dynamics of either cations or anions in different phases of (C5H10NH2)SbCl6.

4

New Tetraoxacyclophanes with alfa,alfa'-Di(para-hydroxyphenyl)-1,4-diisopropylbenzene Structural Unit

Kuś P.

Polish Journal of Chemistry

|

2001

|

Vol. 75, nr 9

1247-1269

EN

alfa,alfa'-Di(para-hydroxyphenyl)-1,4-diisopropylbenzene (1) was used as a precursor for synthesis of six macrocyclic compounds (5-10). Low-temperature crystal structures were determined for _,__-di(4-ethoxyphenyl)-1,4-diisopropylbenzene (3), C30H38O2, monoclinic P21/c, a = 12.831(4), b = 8.708(2), c = 11.221(3) A, Z = 2, and 32,32,39,39- tetramethyl-13-oxo-1,6,20,25-tetraoxa[6.1.6.1.1]paracyclophane (7), C49H53O5, triclinic P1, a = 10.506(2), b = 14.770(2), c = 14.917(2) A,_= 111.91(2), _ = 108.75(2), _ =95.30(2)_, Z = 2. Compound 7 forms 2:1 clathrate-type compound with para-xylene. IR, Raman and UV spectra were recorded for all compounds.