IR Spectra and Vibrational Modes of the Hydrofluoroethers CF3OCH3, CF3OCF2H, and CF3OCF2CF2H and Corresponding Alkanes CF3CH3, CF3CF2H, and CF3CF2CF2H~!2010-03-11~!2010-05-19~!2010-08-06~!

A computational study of octahydridosilasequioxane, Si 8 O 12 H 8 , as a free molecule and when embedded in the unit cell R -3, Z =3, showed that the point group of the free molecule is indeed O h , but that its crystal symmetry is reduced to C 3i . Since the molecular and site-group symmetries influence the vibrational structure of a molecule, a full computational vibrational analysis of the isolated molecule and when embedded in the crystal lattice, is reported here. The analysis of the free molecular spectra given here agrees with that of its experimental infra-red (IR)-spectra and allows the assignment of all the vibrational modes, while the computed phonon dispersion of the crystal confirms the assignment of the internal vibrational modes of the molecule in the crystal. The computed and experimental IR spectra as well as Raman spectra show no indication of serious vibrational intermolecular coupling owing to the presence of multiple molecules in the unit cell. This may be the result of a weak intermolecular vibrational coupling in the solid state, which may feature in the low-frequency modes.

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Vinblastine and vincristine as anticancer molecules stopping the tubulin dimers

Letters in Applied NanoBioScience ◽

10.33263/lianbs91.870874 ◽

2020 ◽

Vol 9 (1) ◽

pp. 870-874

Keyword(s):

Tyrosine Kinase ◽

Ligand Binding ◽

Ir Spectra ◽

Theoretical Calculations ◽

Vinca Alkaloid ◽

Dielectric Constants ◽

Vibrational Modes ◽

Cell Surfaces ◽

Hydrophobic Domain ◽

Chemical Analogue

Vinblastine is belonging to vinca alkaloid family which is a chemical analogue of vincristine molecules. It has a high potential for attaching to tubulin of microtubules, therefore inhibiting the assembly of that biomolecules. Human EGFRs receptors are cell surfaces receptors proteins including three different domains which are known extracellular ligand-binding domain, trans-membranes hydrophobic domain and cytoplasmic C-terminal domain with tyrosine kinase. The Chemical & physical vibrational spectral data obtained from NMR, NBO and IR spectra based on the results of the theoretical calculations using DFT and HF methods. The fundamental vibrational modes were characterized depending on the stabilities of Herceptin in different dielectric constants. Thus, the goal of this article is to evaluate and quantify and qualify of the mechanism in various solvents.

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Macrocycle and substituent vibrational modes of nonplanar nickel(II) octaethyltetraphenylporphyrin from its resonance Raman, near-infrared-excited FT Raman, and FT-IR spectra and deuterium isotope shifts

The Journal of Physical Chemistry ◽

10.1021/j100117a012 ◽

1993 ◽

Vol 97 (15) ◽

pp. 3701-3708 ◽

Cited By ~ 15

Author(s):

Andreas Stichternath ◽

Reinhard Schweitzer-Stenner ◽

Wolfgang Dreybrodt ◽

Ronald S. W. Mak ◽

Xiao Yuan Li ◽

...

Keyword(s):

Ir Spectra ◽

Near Infrared ◽

Resonance Raman ◽

Vibrational Modes ◽

Isotope Shifts ◽

Ft Ir ◽

Ft Raman

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The Nature of Cation–Anion Interactions in Magnetic Ionic Liquids as Revealed Using High-Pressure Fourier Transform Infrared (FT-IR) Spectroscopy

Applied Spectroscopy ◽

10.1177/0003702818805499 ◽

2019 ◽

Vol 73 (5) ◽

pp. 511-519 ◽

Cited By ~ 1

Author(s):

Christopher M. Burba ◽

Hai-Chou Chang

Keyword(s):

High Pressure ◽

Fourier Transform ◽

Ionic Liquids ◽

Ir Spectroscopy ◽

Ir Spectra ◽

Ambient Pressure ◽

Vibrational Modes ◽

Magnetic Ionic Liquids ◽

Ft Ir ◽

Ft Ir Spectroscopy

Magnetic ionic liquids are a group of magneto-responsive compounds that typically possess high ionic conductivities and low vapor pressures. In spite of the general interest in these materials, a number of questions concerning the fundamental interactions among the ions remain unanswered. We used vibrational spectroscopy to gain insight into the nature of these interactions. Intramolecular vibrational modes of the ions are quite sensitive to their local potential energy environments, which are ultimately defined by cation–anion coordination schemes present among the ions. Ambient pressure Fourier transform infrared (FT-IR) spectroscopy indicates comparable interaction motifs for 1-ethyl-3-methylimidazolium tetrachloroferrate(III), [emim]FeCl4, and 1-ethyl-3-methylimidazolium tetrabromoferrate(III), [emim]FeBr4, magnetic ionic liquids. However, the vibrational modes of [emim]FeCl4 generally occur at slightly higher frequencies than those of [emim]FeBr4. These differences reflect different interaction strengths between the [emim]+ cations and [Formula: see text] or [Formula: see text] anions. This conclusion is supported by gas-phase ab initio calculations of single [emim]FeCl4 and [emim]FeBr4 ion pairs that show longer C–H···Br–Fe interaction lengths compared to C–H···Cl–Fe. Although the IR spectra of [emim]FeCl4 and [emim]FeBr4 are comparable at ambient pressure, a different series of spectroscopic changes transpire when pressure is applied to these compounds. This suggests [emim]+ cations experience different types of interaction with the anions under high-pressure conditions. The pressure-dependent FT-IR spectra highlights the critical role ligands attached to the tetrahalogenoferrate(III) anions play in modulating cation–anion interactions in magnetic ionic liquids.

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Quantification of Lipid Phase Order of In Vivo Human Skin Using Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) Spectroscopy and Multivariate Curve Resolution Analysis

Applied Spectroscopy ◽

10.1177/0003702818812738 ◽

2018 ◽

Vol 73 (2) ◽

pp. 182-194 ◽

Cited By ~ 2

Author(s):

Yury Yarovoy ◽

Dane M. Drutis ◽

Thomas M. Hancewicz ◽

Ursula Garczarek ◽

K.P. Ananthapadmanabhan ◽

...

Keyword(s):

Fourier Transform ◽

Ir Spectra ◽

Multivariate Curve Resolution ◽

Lipid Phase ◽

Vibrational Modes ◽

Curve Resolution ◽

Lipid Order ◽

Ft Ir ◽

Left And Right

A new analysis methodology utilizing multivariate curve resolution (MCR) has been successfully combined with Fourier transform infrared (FT-IR) measurement of in vivo human skin to resolve lipid phase constituents in the spectra relative to high and low chain ordering. A clinical study was performed to measure lipid order through different depths of stratum corneum of human subjects. Fourier transform IR spectra were collected through the top 10 layers of the skin on four sites on the left and right forearm of 12 individuals. Depth profiling was achieved by tape stripping to remove layers of skin with 10 successive tapes from each site. In vivo ATR FT-IR spectra were collected after removing each tape. Three isolated spectral regions were analyzed, centered around 2850 cm−1, 1460–1480 cm−1, and 730 cm−1, corresponding to stretching, scissoring, and rocking –CH2 vibrational modes, respectively. Both traditional lipid conformation analysis and MCR analysis were performed on the same spectral data. The lipid order ratio, expressed as the fraction of highly ordered orthorhombic (OR) lipids to the total lipids content (orthorhombic + hexagonal [HEX] + liquid crystal [LC]), was assessed as function of depth. Lipid order depth profiles (LODP) show an increase in order with the stratum corneum depth which can be adequately described by an exponential function for the data obtained in this study. The LODP derived from the three vibrational modes show very similar trends, although the absolute order ratios are somewhat different. The variance of the skin LODP across individuals is much greater than between sites within the same individual. The higher arm sites closer to the elbow on the left and right arm show no statistically significant difference and are recommended for use in comparative studies. The scissoring mode shows the highest sensitivity for determination of LODP value.

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Syntheses and Characterization of Two Dicyanamide Compounds Containing Monovalent Cations: Hg2[N(CN)2]2 and Tl[N(CN)2]

Inorganics ◽

10.3390/inorganics6040135 ◽

2018 ◽

Vol 6 (4) ◽

pp. 135 ◽

Cited By ~ 2

Author(s):

Markus Mann ◽

Olaf Reckeweg ◽

Nils Nöthling ◽

Richard Goddard ◽

Richard Dronskowski

Keyword(s):

Crystal Structure ◽

Ir Spectra ◽

Single Crystal ◽

Diffusion Reaction ◽

Vibrational Modes ◽

Monovalent Cations ◽

Orthorhombic Space Group ◽

Triclinic Space Group ◽

Space Group

Crystals of Hg2[N(CN)2]2 were grown by a slow diffusion-reaction between aqueous Hg2(NO3)2·2H2O and Na[N(CN)2]. Hg2[N(CN)2]2 adopts the triclinic space group P 1 ¯ (no. 2) with a = 3.7089(5), b = 6.4098(6), c = 8.150(6) Å, α = 81.575(6)°, β = 80.379(7)°, γ = 80.195(7)°, and Z = 1. Crystals of Tl[N(CN)2] were obtained from the reaction of TlBr with Ag[N(CN)2] in water. Single-crystal structure analyses evidence that Tl[N(CN)2] is isotypic to α-K[N(CN)2] and adopts the orthorhombic space group Pbcm (no. 57) with a = 8.5770(17), b = 6.4756(13), c = 7.2306(14) Å, and Z = 4. Regarding volume chemistry, the dicyanamide anion occupies ca. 44 cm3·mol−1, and so it corresponds to a large pseudohalide. The IR spectra of both compounds exhibit vibrational modes that are characteristic of the dicyanamide anion.

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Vibrational spectra and phonon dispersion analysis of a single-walled zigzag carbon nanotube: A first principles study

Canadian Journal of Physics ◽

10.1139/cjp-2016-0421 ◽

2016 ◽

Vol 94 (10) ◽

pp. 1112-1118 ◽

Cited By ~ 8

Author(s):

Deepa Sharma ◽

Neena Jaggi

Keyword(s):

Carbon Nanotube ◽

Ir Spectra ◽

Structural Relaxation ◽

First Principles ◽

Density Functional ◽

Phonon Dispersion ◽

Radial Breathing Mode ◽

Dispersion Analysis ◽

Vibrational Modes ◽

Relaxation Factor

This paper reports a vibrational spectroscopic study on a zigzag single-walled carbon nanotube (SWCNT) using the first-principles method based on density functional theory (DFT). The most suitable exchange correlation functional for DFT analysis was determined by comparing the predicted value of band gap of the SWCNT under study with the experimental value reported in the literature. General gradient approximation functional in combination with revised Perdew–Burke–Ernzerh sub-functional was found to give the best results. Using this optimum combination, phonon density of states and phonon dispersion curves have been determined. The analysis of results obtained focuses on symmetry considerations, group theory analysis, segregation of Raman active and infrared (IR) active vibrational modes and interpretation of the Raman and IR spectra obtained. The earlier approaches to the problem rely upon the zone folding technique and force constant models in which structural relaxation factor is not taken care of. An ab initio approach has been adopted by the authors in this work, which is advantageous as it neither depends on some predefined parameter nor does it ignore the structural relaxation factor. Analysis of the Raman spectrum reveals some additional peaks other than the commonly known radial breathing mode, D, G, and G′ bands in the SWCNT spectra, which have been recently reported to be observed experimentally also. Similarly, the theoretically developed IR spectrum for the simulated SWCNT is also in agreement with experimental observations. The methodology presented thus provides a very useful and novel simulation route to predict the vibrational modes, Raman spectra, and IR spectra of SWCNTs theoretically.

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Transmission Infrared Microscopy and Machine Learning Applied to the Forensic Examination of Original Automotive Paint

Applied Spectroscopy ◽

10.1177/00037028211057574 ◽

2021 ◽

pp. 000370282110575

Author(s):

Francis Kwofie ◽

Nuwan Undugodage D. Perera ◽

Kaushalya S. Dahal ◽

George P. Affadu-Danful ◽

Koichi Nishikida ◽

...

Keyword(s):

Machine Learning ◽

Ir Spectra ◽

Vibrational Modes ◽

Correction Algorithm ◽

Spectral Library ◽

Learning Methods ◽

Paint Sample ◽

Machine Learning Methods ◽

Automotive Paint ◽

Large Peak

Alternate least squares (ALS) reconstructions of the infrared (IR) spectra of the individual layers from original automotive paint were analyzed using machine learning methods to improve both the accuracy and speed of a forensic automotive paint examination. Twenty-six original equipment manufacturer (OEM) paints from vehicles sold in North America between 2000 and 2006 served as a test bed to validate the ALS procedure developed in a previous study for the spectral reconstruction of each layer from IR line maps of cross-sectioned OEM paint samples. An examination of the IR spectra from an in-house library (collected with a high-pressure transmission diamond cell) and the ALS reconstructed IR spectra of the same paint samples (obtained at ambient pressure using an IR transmission microscope equipped with a BaF2 cell) showed large peak shifts (approximately 10 cm−1) with some vibrational modes in many samples comprising the cohort. These peak shifts are attributed to differences in the residual polarization of the IR beam of the transmission IR microscope and the IR spectrometer used to collect the in-house IR spectral library. To solve the problem of frequency shifts encountered with some vibrational modes, IR spectra from the in-house spectral library and the IR microscope were transformed using a correction algorithm previously developed by our laboratory to simulate ATR spectra collected on an iS-50 FT-IR spectrometer. Applying this correction algorithm to both the ALS reconstructed spectra and in-house IR library spectra, the large peak shifts previously encountered with some vibrational modes were successfully mitigated. Using machine learning methods to identify the manufacturer and the assembly plant of the vehicle from which the OEM paint sample originated, each of the twenty-six cross-sectioned automotive paint samples was correctly classified as to the “make” and model of the vehicle and was also matched to the correct paint sample in the in-house IR spectral library.

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MOLECULAR STRUCTURE AND VIBRATION SPECTRA OF PIVALIC ACID

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/tcct.20165907.5412 ◽

2018 ◽

Vol 59 (7) ◽

pp. 17

Author(s):

Alexander E. Pogonin ◽

Oleg A. Pimenov ◽

Yuriy A. Zhabanov

Keyword(s):

Molecular Structure ◽

Ir Spectra ◽

Gas Phase ◽

Metal Ion ◽

Density Functional ◽

Pivalic Acid ◽

Basis Sets ◽

Potential Energy Distribution ◽

Central Metal ◽

Vibrational Modes

The metal carboxylates such as metal pivalates (salts of the pivalic acid (CH3)3CCOOH) attract a great interest as most promising precursors for chemical vapor deposition (CVD) technology. The possibility to use these substances in the CVD technology is specified by their good thermal stability and high volatility. For modeling of chemical reactions with metal pivalates in the gas-phase and the data on molecular structure will be very useful, in particularly information about effect of central metal ion to geometry of pivalic ligands. In the frame of this task the structures of metal pivalate molecules and pivalic acid (H(piv)) in a gas phase should be finding. The aim of present work is theoretical investigation of the geometry and IR-spectrum of H(piv) using density functional theory (DFT) methods. All calculations were performed using the Gaussian 03 program. The optimization of geometry and quadratic force field calculations were carried out using DFT functionals B3LYP, PBE, PBE0 and BP86 with correlation-consistent triple-ζ valence cc-pVTZ basis sets for O, C, and H. Appropriate assignment of vibrational modes was carried out by the potential energy distribution (PED) analysis among internal coordinates using the SHRINK program. According to DFT computations, the H(piv) molecule has an equilibrium structure of Cs symmetry with Гvib=26A'+19A''. The theoretical and experimental IR-spectra are satisfactorily agreed. The comparison of the ten intensities of highest bands in spectra allowed determining linear correlation between peaks position in experimental and modeling IR-spectra. It should be note the complicated composition of vibrational modes.

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