Interpretation of experimental IR spectra of (z)-4-(2- (acryloyloxy)ethoxy)-4-oxobut-2-enoic acid and its polymers

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Chen Song ◽  
Xiaoyu Li
Keyword(s):  
Ir Spectra ◽  
Density Functional ◽  
Solid Phase ◽  
Enoic Acid ◽  
Field Calculation ◽  
Double Bonds ◽  
Absorption Bands ◽  
Experimental Ir ◽  
Functional Theory ◽  
Full Structure

AbstractThe solid phase FTIR spectra of (z)-4-(2-(acryloyloxy)ethoxy)-4-oxobut- 2-enoic acid (cis-AEOEA) and its polymers have been recorded in the regions 3500~500 cm-1, respectively. The IR spectra of cis-AEOEA was interpreted with the aid of normal coordinated analysis following full structure optimization and force field calculation based on density functional theory (DFT). Standard scaling factor was used to afford better correspondence between the calculated and experimental wavenumbers for the separation and unambiguous identification of observed IR spectra of cis-AEOEA, especially for C=C double bonds. The characteristic absorption bands of C=C are used for identifying the kind of C=C double bonds in cis-AEOEA’s polymers.

scholarly journals Theoretical and infrared spectroscopy study of the structure of copper(II) poly-5-vinyltetrazolate and the products of its thermolysis

2020 ◽  
pp. 19-31
Author(s):  
Vitaly E. Matulis ◽  
Ekaterina G. Ragoyja ◽  
Alexander V. Zuraev ◽  
Yuri V. Grigoriev ◽  
Oleg A. Ivashkevich
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectra ◽  
Ir Spectrum ◽  
Density Functional ◽  
Molecular Electrostatic Potential ◽  
Thermolysis Product ◽  
High Catalytic Activity ◽  
Experimental Ir ◽  
Functional Theory ◽  
Model Structures

The structure of copper(II) poly-5-vinyltetrazolate and the products of its thermolysis has been studied by means of density functional theory and infrared spectroscopy. Copper(II) poly-5-vinyltetrazolate has been obtained and subsequently subjected to thermolysis. Infrared spectra of copper(II) poly-5-vinyltetrazolate and the products of its thermolysis have been recorded. The possible ways of coordination of copper(II) ions with tetrazole-containing ligands were established by analyzing the calculated molecular electrostatic potential distribution and comparing the calculated IR-spectra of the model structures to the experimental ones. It has been shown that the best agreement between the calculated and experimental data is observed for the model with three-coordinated copper(II) ions, which includes both the tetrazole-containing ligands coordinating two copper(II) ions through N(1)- and N(3)-atoms of the tetrazole ring, and the tetrazolecontaining ligands coordinating one copper(II) ion through either the N(2)- or the N(3)-atom. Recently we have shown that the product of thermolysis of copper(II) poly-5-vinyltetrazolate exhibits high catalytic activity in homocoupling of phenylacetylene and Huisgen [3 + 2]-cycloaddition. To establish the structure of the products of thermolysis of copper(II) poly-5-vinyltetrazolate, seven possible products have been proposed based on the analysis of the structure of copper(II) poly-5-vinyltetrazolate and the experimental IR-spectrum. IR-spectra of all proposed products have been calculated and the results of the calculations have been compared with the experimental IR-spectrum of copper(II) poly-5-vinyltetrazolate thermolysis product. It has been shown that the main product of thermolysis is cis-polycyanoacetylene.

scholarly journals Modelling IR Spectra of Sulfonated Polyether Ether Ketone (SPEEK) Membranes for Fuel Cells

2020 ◽  
Vol 850 ◽  
pp. 138-143
Author(s):  
Guntars Vaivars ◽  
Kristīne Krūkle-Bērziņa ◽  
Madara Markus
Keyword(s):  
Ir Spectra ◽  
Density Functional ◽  
Cross Linking ◽  
Experimental Ir ◽  
Functional Theory ◽  
Polyether Ether Ketone ◽  
Sulfonated Polyether Ether Ketone ◽  
Membrane Geometry ◽  
Ether Ketone ◽  
Speek Membrane

SPEEK (sulfonated polyether ether ketone) membranes have been prepared and characterized. The SPEEK membrane geometry and theoretical vibration spectra calculated using density functional theory (DFT) as depending from membrane chain length and polymer cross-linking. Analyzed the limitations of the method by comparing theoretical and experimental IR spectra.

scholarly journals Terahertz Absorption Spectroscopy of Benzamide, Acrylamide, Caprolactam, Salicylamide, and Sulfanilamide in the Solid State

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ye Jiang ◽  
Fengshan Zhou ◽  
Xiaodong Wen ◽  
Limin Yang ◽  
Guozhong Zhao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Absorption Spectra ◽  
Density Functional ◽  
Room Temperature ◽  
Solid Phase ◽  
Absorption Bands ◽  
Functional Theory ◽  
Terahertz Absorption ◽  
Thz Absorption

Terahertz (THz) absorption spectra of the similarly structured molecules with amide groups including benzamide, acrylamide, caprolactam, salicylamide, and sulfanilamide in the solid phase at room temperature and 7.8 K for salicylamide are reported and compared to infrared vibrational spectral calculations using density functional theory. The results of THz absorption spectra show that the molecules have characteristic bands in the region of 0.2–2.6 THz (~7–87 cm−1). THz technique can be used to distinguish different molecules with amide groups. In the THz region benzamide has three bands at 0.83, 1.63, and 1.73 THz; the bands are located at 1.44 and 2.00 THz for acrylamide; the bands at 1.24, 1.66 and 2.12 THz are observed for caprolactam. The absorption bands are located at 1.44, 1.63, and 2.39 THz at room temperature, and at 1.22, 1.46, 1.66, and 2.41 THz at low temperature for salicylamide. The bands at 1.63, 1.78, 2.00, and 2.20 THz appear for sulfanilamide. These bands in the THz region may be related to torsion, rocking, wagging, and other modes of different groups in the molecules.

scholarly journals Scaled quantum chemical studies of the structural and vibrational spectra of acetyl coumarin

2006 ◽  
Vol 4 (4) ◽  
Author(s):  
Khaled Bahgat
Keyword(s):  
Density Functional ◽  
Solid Phase ◽  
Normal Modes ◽  
Basis Sets ◽  
Functional Theory ◽  
Hartree Fock ◽  
Full Structure ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Ft Ir

AbstractThe solid phase FT-IR and FR-Raman spectra of acetyl coumarin have been recorded in the regions 4000–50 cm−1. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on density functional theory (DFT) and Hartree-Fock (HF) at 6–31G* and 6–311++G** basis sets. The resulting force fields were transformed to internal coordinates, the calculated vibrational frequencies and normal modes were utilized in the assignment of the observed vibrational fundamentals. The measured spectral data were used to refine the vibrational force constants by means of a small number of scaling factors.

scholarly journals Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christian Wiebeler ◽  
Joachim Vollbrecht ◽  
Adam Neuba ◽  
Heinz-Siegfried Kitzerow ◽  
Stefan Schumacher
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Energy Levels ◽  
Spectroscopic Properties ◽  
Absorption Bands ◽  
Functional Theory ◽  
Vertical Excitation ◽  
Hartree Fock ◽  
Tauc Plot ◽  
Electrochemical Approach

AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

scholarly journals Vibrational Study and Force Field of the Citric Acid Dimer Based on the SQM Methodology

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Laura Cecilia Bichara ◽  
Hernán Enrique Lanús ◽  
Evelina Gloria Ferrer ◽  
Mónica Beatriz Gramajo ◽  
Silvia Antonia Brandán
Keyword(s):  
Citric Acid ◽  
Force Field ◽  
Density Functional ◽  
Solid Phase ◽  
Dft Method ◽  
Electronic Charge ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Atoms In Molecules Theory ◽  
Best Fit

We have carried out a structural and vibrational theoretical study for the citric acid dimer. The Density Functional Theory (DFT) method with the B3LYP/6-31G∗ and B3LYP/6-311++ methods have been used to study its structure and vibrational properties. Then, in order to get a good assignment of the IR and Raman spectra in solid phase of dimer, the best fit possible between the calculated and recorded frequencies was carry out and the force fields were scaled using the Scaled Quantum Mechanic Force Field (SQMFF) methodology. An assignment of the observed spectral features is proposed. A band of medium intensity at 1242  together with a group of weak bands, previously not assigned to the monomer, was in this case assigned to the dimer. Furthermore, the analysis of the Natural Bond Orbitals (NBOs) and the topological properties of electronic charge density by employing Bader's Atoms in Molecules theory (AIM) for the dimer were carried out to study the charge transference interactions of the compound.

scholarly journals Н-комплексы 1,2-нафтохинона с молекулами воды в водном растворе и их влияние на сдвиги полос поглощения

2021 ◽  
Vol 129 (5) ◽  
pp. 599
Author(s):  
С.Н. Цеплина ◽  
E.E. Цеплин
Keyword(s):  
Quantum Chemical ◽  
Continuum Model ◽  
Density Functional ◽  
Water Solution ◽  
Polarizable Continuum Model ◽  
Water Molecules ◽  
Absorption Bands ◽  
Functional Theory ◽  
Polarizable Continuum ◽  
Polar Water

Optical absorption spectra of 1,2-naphthoquinone in non-polar (n-hexane) and polar (water) solvents were obtained. It is shown that the use of quantum chemical calculations based on time-dependent density functional theory (TDDFT B3LYP/6-311+G(d, p)) with the polarizable continuum model (PCM) for calculating 1,2-naphthoquinone in a solution of n-hexane and hydrogen complex of 1,2-naphthoquinone with two water molecules in an aqueous medium describes well the shifts of the absorption bands of 1,2-naphthoquinone in a water solution compared to a solution in n-hexane. Based on the analysis of deviations of the calculated band shifts from the experimental ones, the question of the formation of 1,2-naphthoquinone hydrogen complexes with n water molecules (n = 1-4) in an aqueous solution is considered.

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