CONTRIBUTION TO THE INFRARED SPECTRA OF FIVE-MEMBERED N- AND N,S-HETEROCYCLIC COMPOUNDS

1964 ◽  
Vol 42 (1) ◽  
pp. 43-49 ◽  
Author(s):  
C. N. R. Rao ◽  
R. Venkataraghavan
Keyword(s):  
Infrared Spectra ◽  
Oxidation Product ◽  
Heterocyclic Compounds ◽  
Plane Deformation ◽  
Deformation Bands ◽  
Hydrogen Atoms ◽  
Benzene Rings ◽  
Out Of Plane ◽  
Heterocyclic Derivatives

Infrared spectra of 5-membered N- and N,S-heterocyclic derivatives such as triazoles, tetrazoles, thiazoles, thiadiazoles, thiatriazoles, and dithiazoles have been examined and empirical assignments have been made. The spectra of the two dithiazolidine derivatives, isoperthiocyanic acid and oxidation product of dithiobiuret, have been studied in detail. Assignments for benzthiazole derivatives are reported. The CH out-of-plane deformation bands of benzene rings fused to five-membered heterocyclic rings have been found to be in the region 760–740 cm−1, characteristic of four adjacent benzenoid hydrogen atoms.

Effect of functional group conformation on the infrared spectra of some gem difunctional phenylethylene derivatives

1969 ◽  
Vol 47 (17) ◽  
pp. 3147-3152 ◽  
Author(s):  
D. J. Currie ◽  
C. E. Lough ◽  
F. K. McClusky ◽  
H. L. Holmes
Keyword(s):  
Absorption Band ◽  
Functional Groups ◽  
Infrared Spectra ◽  
Functional Group ◽  
Plane Deformation ◽  
Carbonyl Groups ◽  
Deformation Bands ◽  
Or Groups ◽  
Out Of Plane ◽  
Stretching Vibrations

Except for the benzalmalononitriles, two functional group stretching vibrations occur in the infrared (i.r.) spectra of the β,β-difunctional-styrenes with similar functional groups. For geometrically homogeneous compounds with dissimilar functional groups only one absorption band occurs for each functional group. The two bands for similar functional groups have been ascribed to S-cis- and S-trans-conformations of the carbonyl groups with respect to the ethylene and variation in the frequencies of each of these oriented carbonyls to rotation of the functional group or groups out of the plane of the ethylene by steric factors.Frequencies for ethylenic C—H out of plane deformation bands for β-monofunctional styrenes accorded with those already assigned to this vibration. A similar assignment could not be made for the difunctional analogues.

Pyrrole studies. VIII. The NH stretching frequencies of substituted pyrroles Acetyl and benzoyl substituents

1966 ◽  
Vol 19 (1) ◽  
pp. 107 ◽  
Author(s):  
RW Guy ◽  
RA Jones
Keyword(s):  
Carbon Tetrachloride ◽  
High Resolution ◽  
Frequency Band ◽  
Infrared Spectra ◽  
Plane Deformation ◽  
Acyl Substituent ◽  
Out Of Plane ◽  
Lower Frequency Band ◽  
Hot Band ◽  
Substituted Pyrroles

The infrared spectra of a number of acylpyrroles have been examined in the NH and CO stretching region under high resolution in carbon tetrachloride. Analysis of the data show-s that the effect of each group on the NH stretching frequency is independent of other substituents and additive. Pyrroles having the acyl substituent in the β-position show two concentration-independent bands. The lower frequency band arises from interaction with the out-of-plane deformation of the NH group, producing a hot band.

scholarly journals Simulated NIR spectra as sensitive markers of the structure and interactions in nucleobases

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Krzysztof B. Beć ◽  
Justyna Grabska ◽  
Yukihiro Ozaki ◽  
Mirosław A. Czarnecki ◽  
Christan W. Huck
Keyword(s):  
Near Infrared ◽  
Plane Deformation ◽  
Vibrational Analysis ◽  
Nir Spectroscopy ◽  
Full Potential ◽  
Molecular Models ◽  
Deformation Bands ◽  
Near Ir ◽  
Out Of Plane ◽  
First Time

AbstractNear-infrared (near-IR; NIR) spectroscopy is continuously advancing in biophysical and biochemical fields of investigation. For instance, recent progresses in NIR hyperspectral imaging of biological systems may be noted. However, interpretation of NIR bands for biological samples is difficult and creates a considerable barrier in exploring the full potential of NIR spectroscopy in bioscience. For this reason, we carried out a systematic study of NIR spectra of adenine, cytosine, guanine, and thymine in polycrystalline state. Interpretation of NIR spectra of these nucleobases was supported by anharmonic vibrational analysis using Deperturbed Vibrational Second-Order Perturbation Theory (DVPT2). A number of molecular models of nucleobases was applied to study the effect of the inter-molecular interactions on the NIR spectra. The accuracy of simulated NIR spectra appears to depend on the intra-layer interactions; in contrast, the inter-layer interactions are less influential. The best results were achieved by combining the simulated spectra of monomers and dimers. It is of particular note that in-plane deformation bands are far more populated than out-of-plane ones and the importance of ring modes is relatively small. This trend is in contrast to that observed in mid-IR region. As shown, the local, short-range chemical neighborhood of nucleobase molecules influence their NIR spectra more considerably. This suggests that NIR spectra are more sensitive probe of the nucleobase pairing than mid-IR ones. The obtained results allow, for the first time, to construct a frequency correlation table for NIR spectra of purines and pyrimidines.

THE INFRARED AND THE NEAR-ULTRAVIOLET ABSORPTION SPECTRA OF POLYPHENYL DERIVATIVES OF THE ELEMENTS OF GROUPS IVb AND Vb

1961 ◽  
Vol 39 (1) ◽  
pp. 171-179 ◽  
Author(s):  
C. N. R. Rao ◽  
J. Ramachandran ◽  
A. Balasubramanian
Keyword(s):  
Absorption Spectra ◽  
Infrared Spectra ◽  
Ultraviolet Absorption ◽  
Para Position ◽  
Near Ultraviolet ◽  
Benzene Rings ◽  
Out Of Plane ◽  
Reactivity Constant ◽  
Derivatives Of ◽  
Absorption Frequencies

The near-ultraviolet absorption spectra of polyphenyl derivatives of the IVb and Vb elements have been studied in detail. In the case of the triphenyl derivatives of the Vb elements, the unshared p-electrons on the central atoms interact strongly with the π-orbitals of the benzene rings. When the central atoms do not possess unshared electrons as in the case of the derivatives of the IVb and the pentavalent Vb elements, there appears to be no such resonance interaction. The Hammett reactivity constants of the para- and meta-trityl, triphenylsilyl, and triphenylgermanyl groups are estimated to be close to zero. However, the reactivity constant of the triphenylsilyl group in the para position of phenol is estimated to be about 0.30. The infrared spectra of the phenyl derivatives of the IVb and Vb elements show smooth trends due to mass effects of the central atoms, in the C=C skeletal, C—H out-of-plane, and other vibrations. The absorption frequencies which are assigned to the phosphorus-phenyl and silicon–phenyl bonds in the literature do not appear to be unique for these linkages.

Infrared Spectra of 2,9-Dimethyl-1,10-phenanthroline, Its Hydrates and Acid Perchlorate

1962 ◽  
Vol 15 (3) ◽  
pp. 425 ◽  
Author(s):  
ECM Grigg ◽  
JR Hall ◽  
RA Plowman
Keyword(s):  
Infrared Spectra ◽  
Plane Motion ◽  
Ring System ◽  
Hydrogen Atoms ◽  
Absorption Bands ◽  
Out Of Plane ◽  
Intense Absorption ◽  
Infrared Absorption Spectra ◽  
Stretching Vibrations ◽  
Phase Out

Infrared absorption spectra of 2,9-dimethyl-1,10-phenanthroline (dmp), dmp 0.5H2O, dmp 2H2O, and dmp HClO4 have been obtained over the range 4000-650 cm-1. Bands between 1610 and 1545 cm-1 are attributed to stretching vibrations within the phenanthroline ring system. The in-phase out-of-plane motion of the ring hydrogen atoms is associated with intense absorption at 845 cm-1. A strong band is observed at 728 cm-1 which cannot be accounted for in terms of an out-of-plane CH deformation. The perchlorate is characterized by shifts of the strongest absorption bands observed in the spectra of dmp and the hydrates.

Single Heterocyclic Compounds as Monoamine Oxidase Inhibitors: From Past to Present

2020 ◽  
Vol 20 (10) ◽  
pp. 908-920 ◽  
Author(s):  
Su-Min Wu ◽  
Xiao-Yang Qiu ◽  
Shu-Juan Liu ◽  
Juan Sun
Keyword(s):  
Monoamine Oxidase ◽  
Heterocyclic Compounds ◽  
Biological Activities ◽  
The Past ◽  
Structure Activity ◽  
Receptor Interactions ◽  
Heterocyclic Derivatives ◽  
Inhibitory Activities ◽  
Leading Compounds ◽  
Heterocyclic Moiety

Inhibitors of monoamine oxidase (MAO) have shown therapeutic values in a variety of neurodegenerative diseases such as depression, Parkinson’s disease and Alzheimer’s disease. Heterocyclic compounds exhibit a broad spectrum of biological activities and vital leading compounds for the development of chemical drugs. Herein, we focus on the synthesis and screening of novel single heterocyclic derivatives with MAO inhibitory activities during the past decade. This review covers recent pharmacological advancements of single heterocyclic moiety along with structure- activity relationship to provide better correlation among different structures and their receptor interactions.

scholarly journals Characterization and ballistic performance of thin pre-damaged resin-starved aramid-fiber composite panels

2021 ◽  
pp. 004051752110134
Author(s):  
Cerise A Edwards ◽  
Stephen L Ogin ◽  
David A Jesson ◽  
Matthew Oldfield ◽  
Rebecca L Livesey ◽  
...  
Keyword(s):  
Fiber Composite ◽  
Plane Deformation ◽  
Ballistic Impact ◽  
Image Correlation ◽  
Composite Panel ◽  
Composite Panels ◽  
Micro Computed Tomography ◽  
Ballistic Performance ◽  
Low Level ◽  
Out Of Plane

Military personnel use protective armor systems that are frequently exposed to low-level damage, such as non-ballistic impact, wear-and-tear from everyday use, and damage during storage of equipment. The extent to which such low-level pre-damage could affect the performance of an armor system is unknown. In this work, low-level pre-damage has been introduced into a Kevlar/phenolic resin-starved composite panel using tensile loading. The tensile stress–strain behavior of this eight-layer material has been investigated and has been found to have two distinct regions; these have been understood in terms of the microstructure and damage within the composite panels investigated using micro-computed tomography and digital image correlation. Ballistic testing carried out on pristine (control) and pre-damaged panels did not indicate any difference in the V50 ballistic performance. However, an indication of a difference in response to ballistic impact was observed; the area of maximal local out-of-plane deformation for the pre-damaged panels was found to be twice that of the control panels, and the global out-of-plane deformation across the panel was also larger.

scholarly journals In-Process Measurement of Three-Dimensional Deformations Based on Speckle Photography

2021 ◽  
Vol 11 (11) ◽  
pp. 4981
Author(s):  
Andreas Tausendfreund ◽  
Dirk Stöbener ◽  
Andreas Fischer
Keyword(s):  
Evaluation Method ◽  
Process Analysis ◽  
Plane Deformation ◽  
Three Dimensional ◽  
Machining Process ◽  
Image Correlation ◽  
Speckle Photography ◽  
Process Measurement ◽  
Out Of Plane ◽  
Plane Deformations

In the concept of the process signature, the relationship between a material load and the modification remaining in the workpiece is used to better understand and optimize manufacturing processes. The basic prerequisite for this is to be able to measure the loads occurring during the machining process in the form of mechanical deformations. Speckle photography is suitable for this in-process measurement task and is already used in a variety of ways for in-plane deformation measurements. The shortcoming of this fast and robust measurement technique based on image correlation techniques is that out-of-plane deformations in the direction of the measurement system cannot be detected and increases the measurement error of in-plane deformations. In this paper, we investigate a method that infers local out-of-plane motions of the workpiece surface from the decorrelation of speckle patterns and is thus able to reconstruct three-dimensional deformation fields. The implementation of the evaluation method enables a fast reconstruction of 3D deformation fields, so that the in-process capability remains given. First measurements in a deep rolling process show that dynamic deformations underneath the die can be captured and demonstrate the suitability of the speckle method for manufacturing process analysis.

Inverse algorithm for out-of-plane deformation in shearography

2021 ◽  
Vol 53 (1) ◽  
Author(s):  
Shuangle Wu ◽  
Fangyuan Sun ◽  
Haotian Xie ◽  
Qihan Zhao ◽  
Peizheng Yan ◽  
...  
Keyword(s):  
Plane Deformation ◽  
Inverse Algorithm ◽  
Out Of Plane
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