scholarly journals A study of the IR spectra of copigments formed by malvin chloride with flavones

2000 ◽  
Vol 65 (4) ◽  
pp. 245-253 ◽  
Author(s):  
Ubavka Mioc ◽  
Jasmina Dimitric-Markovic ◽  
Jelisaveta Baranac
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Formation Mechanism ◽  
Equilibrium Constants ◽  
Formed Hydrogen

Research into the essence of the process of copigmentation of anthocyan molecules was continued by applying IR spectroscopy, in an attempt to elucidate the formation mechanism of copigment molecules between malvin chloride and several variously substituted flavones. Analysis of the IR spectra of the formed copigments revealed that the process of copigmentation is achieved via the formation of hydrogen bonds. The strength of the formed hydrogen bonds was correlated with the equilibrium constants of the processes of copigmentation of these molecules. The found correlation was in accordance with the supposed mechanism of the copigmentation reaction.

scholarly journals A study of the ir spectra of the copigments of malvin chloride with organic acids

2001 ◽  
Vol 66 (7) ◽  
pp. 451-462 ◽  
Author(s):  
Jasmina Dimitric-Markovic ◽  
Ubavka Mioc ◽  
Jelisavetam Baranac ◽  
Zoran Nedic
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Thermodynamic Properties ◽  
Organic Acids ◽  
Ir Spectra ◽  
Infrared Spectra ◽  
Molecular Structures ◽  
Oxonium Ions ◽  
Hydroxy Groups ◽  
Formed Hydrogen

The infrared spectra of the copigments of malvin with several organic acids: caffeic, ferulic, sinapic, chlorogenic, and tannic, were analyzed in order to elucidate the bonding of the molecules in the copigments. It was established that copigmentation is realized through hydrogen bonding between malvin molecules and the acids under study. The infrared spectra reveal that two groups of hydrogen bonds are formed, which include interactions of different molecular structures: hydroxy groups (bands around 3500 cm-1) and oxonium ions of the molecules (bands below 3000 cm-1). The formed hydrogen bonds were found to be of different strengths. The strengths of the hydrogen bonds were tentatively correlated with thermodynamic properties of the corresponding copigmentation reactions.

Evaluation of Electrospun Poly (Vinyl Alcohol) (PVA)/Gelatin Nanofiber Membrane and Biocompatibility

2010 ◽  
Vol 97-101 ◽  
pp. 2249-2252 ◽  
Author(s):  
Chao Chiung Huang ◽  
Chao Tsang Lu ◽  
Chieh Yu Chao ◽  
Tina Cu Huang ◽  
Ching Wen Lou ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Electric Field ◽  
Ir Spectra ◽  
Vinyl Alcohol ◽  
Volume Ratio ◽  
Poly Vinyl Alcohol ◽  
Electrospun Nanofiber ◽  
Nanofiber Membrane ◽  
Intermolecular Hydrogen Bonds

PVA and gelatin mixed in various volume ratios (100:0, 90:20, 80:20, 70:30, 60:40, 50:50, to 0:100). The effects of the volume ratio on the spinnability of PVA/gelatin solutions were evaluated. The effect on the electrospun nanofiber of PVA/gelatin was examined by IR spectroscopy. Experimental results have demonstrated that solutions of PVA/gelatin in a volume ratio of 80/20 had good spinnability. As the electric field increased, the numbers of beads and droplet decreased. IR spectra demonstrated strong intermolecular hydrogen bonds between the molecules of gelatin and PVA. In this investigation, the best electric field for electrospinning was 0.68 kV/cm. The critical electric field for electrospinning is 0.5 kV/cm.

Evolution structurale de la nacrite en fonction de la nature des molécules organiques intercalees

2000 ◽  
Vol 33 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
A. Ben Haj Amara ◽  
H. Ben Rhaiem ◽  
A. Plançon
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Dimethyl Sulfoxide ◽  
Organic Molecules ◽  
Interlayer Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intercalated Compounds ◽  
Xrd Study ◽  
Intercalation Process

Nacrite has been intercalated with two polar organic molecules: dimethyl sulfoxide (DMSO) andN-methylacetamide (NMA). The homogeneous nacrite complexes have been studied by X-ray diffraction (XRD) and infrared (IR) spectroscopy. The XRD study is based on a comparison between experimental and calculated patterns. The structures of the intercalated compounds have been determined, including the mutual positions of the layers after intercalation and the positions of the intercalated molecules in the interlayer space. It has been shown that the intercalation process causes not only a swelling of the interlayer space but also a shift in the mutual in-plane positions of the layers. This shift depends on the nature of the intercalated molecules and is related to their shape and the hydrogen bonds which are established with the surrounding surfaces. For a given molecule, the intercalation process is the same for the different polytypes of the kaolinite family. These XRD results are consistent with those of IR spectroscopy.

scholarly journals Evaluation of solubility and histological effect of 11-keto-β-Boswellic acid on the diabetic mice liver using FTIR-PCA analysis and microscopy

2021 ◽  
Author(s):  
I.S. Al-Amri ◽  
F. Mabood ◽  
I.T. Kadim ◽  
A.Y. Alkindi ◽  
A. Al-Harrasi ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Liver Tissue ◽  
Diabetic Control ◽  
Control Group ◽  
Diabetic Mice ◽  
Boswellic Acid ◽  
Ft Ir ◽  
Mice Liver ◽  
Ft Ir Spectroscopy

ABSTRACTThis study was designed to develop a rapid, sensitive, accurate, and inexpensive Fourier Transform Infrared Reflectance (FT-IR) Spectroscopy coupled with Principle Component Analysis (PCA) as a detection technique to evaluate the solubility of 11-Keto-β-Boswellic acid (KBA), from the gum resin extracted from the Omani frankincense, (Boswellia sacra) in the liver of STZ induced diabetic mice. This study also investigated the effect of KBA on the histological changes of hepatocytes of diabetic mice. Liver tissue samples from three groups of mice included normal control group, diabetic control group and diabetic group treated IP with KBA were scanned with FT-IR spectrophotometer in the reflection mode. FT-IR Spectra were collected in the wavenumber range from 400 to 4000cm-1 using ATR accessorry. The results of FT-IR Spectra were analyzed by using multivariate method Principle Component Analysis. The PCA score plot is an exploratory multivariate method indicated that there was a complete segregation among the three groups of liver samples based on change in variation of position of wavenumber in FT-IR spectra, which revealed that there is a clear effect of KBA solubility on treatments. The histological features showed an improvement in the liver tissues with normal structures of hepatocytes with exhibiting mild vacuolations in their cytoplasm. In conclusion, reflectance FT-IR spectroscopy coupled with PCA could be deployed as a new detection method for rapid, low cost and non-destructive method for evaluating of treatment effects in diseased liver tissue based on the solubility of KBA. Histological findings demonstrated the protective effective of KBA on improving the morphology of liver tissue in diabetic mice which resulted in complete recovery to the damage observed in diabetic control group.Summary StatementReflectance FT-IR spectroscopy coupled with PCA has been deployed as a new rapid, inexpensive and non-destructive detection method to examine the solubility of 11-keto-β-Boswellic acid (KBA) in streptozotocin (STZ) induced-diabetes mice liver tissue following intraperitoneal treatment. Moreover, microscopic study of liver tissue histopathology revealed that KBA has a protecting effect against STZ damage.

A Zinc(II)-Silver(I) Bimetallic Coordination Polymer Assembled Through Argentophilic and π-π Interactions, f[Zn(phen)2(H2O) {Ag(CN)2g][Ag(CN)2]·MeOH}n (phen=1,10-Phenanthroline)

2013 ◽  
Vol 68 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Muhammad Monim-ul-Mehbooba ◽  
Muhammad Ramzan ◽  
Tobias Rüffe ◽  
Heinrich Lang ◽  
Shafqat Naddem ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Ir Spectroscopy ◽  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
X Ray ◽  
Π Interactions ◽  
X Ray Crystallography ◽  
3D Network ◽  
Argentophilic Interactions

A cyanido-bridged Zn(II)-Ag(I) bimetallic coordination polymer, {[Zn(phen)2(H2O){Ag(CN)2}] [Ag(CN)2]·MeOH}n (1), was prepared using ZnCl2, 1,10-phenanthroline (phen) and K[Ag(CN)2] and characterized by IR spectroscopy, thermal analysis and X-ray crystallography. The crystal structure of 1 consists of dinuclear [Zn(phen)2(H2O){Ag(CN)2}]+ cations, [Ag(CN)2]- anions and a methanol molecule. The non-coordinated [Ag(CN)2]- anions are linked to the [Zn(phen)2(H2O){Ag(CN)2}]+ complex cations through argentophilic interactions leading to the formation of chains. The chains are connected by hydrogen bonds and π-π interactions to give a 3D network.

Influence of KBr conditioning on the infrared hydroxyl-stretching region of saponites

Clay Minerals ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 439-445 ◽  
Author(s):  
M. Pelletier ◽  
L. J. Michot ◽  
O. Barrès ◽  
B. Humbert ◽  
S. Petit ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Clay Minerals ◽  
Diffuse Reflectance ◽  
Layer Charge ◽  
Tetrahedral Sheet ◽  
Stretching Vibration ◽  
Sheet Charge

AbstractIn order to assess the influence of tetrahedral sheet charge on the hydroxyl-stretching vibration in clay minerals, a series of synthetic Na-saponites, with increasing layer charge, was studied by infrared (IR) spectroscopy. When recorded after KBr dilution either in transmission or diffuse reflectance, the IR spectra exhibit a component at ~3710 cm-1, the intensity of which increases linearly with increasing layer charge. When experiments are carried out without any dilution of the samples, this component is not observed, suggesting a Na+/K+ exchange upon mixing of the sample with KBr. The spectra obtained for K-saponite confirm this exchange. This shows that the dilution procedure can lead to serious misinterpretations of IR spectra in the OH-stretching region.

scholarly journals Application of FT-IR spectroscopy in detection of food hydrocolloids  in confectionery jellies and food supplements

2013 ◽  
Vol 19 (No. 2) ◽  
pp. 51-56 ◽  
Author(s):  
J. Čopíková ◽  
M. Černá ◽  
M. Novotná ◽  
J. Kaasová ◽  
A. Synytsya
Keyword(s):  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Food Products ◽  
Food Supplements ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

FT-IR spectra of isolated high molecule fractions were measured and used for identification of food hydrocolloids in confectionery jellies and food supplements. The simple comparison of spectra of standards and samples proved that this technique is useful for the monitoring of food hydrocolloids in particular food products.

An infrared study of the interaction between ethyl N-(diphenylmethylene)glycinate with proton donors: comparison with N-benzylidenemethylamine

1986 ◽  
Vol 64 (12) ◽  
pp. 2305-2309 ◽  
Author(s):  
Marleen Ruysen ◽  
Thérèse Zeegers-Huyskens
Keyword(s):  
Hydrogen Bond ◽  
Ir Spectra ◽  
Equilibrium Constants ◽  
Lone Pair ◽  
Imino Group ◽  
Infrared Study ◽  
Hydrogen Bond Formation ◽  
Hydroxy Proton ◽  
Proton Donors ◽  
Intramolecular Hydrogen

The interaction between ethyl N-(diphenylmethylene)glycinate (DPG) and hydroxy proton donors or pyrrole has been investigated by ir spectrometry. The equilibrium constants, enthalpies, and entropies of complex formation have been determined in carbon tetrachloride solution and compared with the data obtained for the complexes involving N-benzylidene-methylamine and the same proton donors. The ir spectra studied mainly in the νOH, νC=N, νC=O, and νC—O regions suggest that hydrogen bond formation occurs at the N atom of the imino group and at the O atom of the carbonyl group. The results are discussed in terms of the basicity at the two acceptor sites and of the accessibility of the lone pair of electrons. The ir spectra of the solid adduct of DPG with HCl show that protonation takes place on the N atom. The protonated structure is possibly stabilized by an intramolecular hydrogen bond.

scholarly journals Discussion on the formation mechanism of polycarbosilane by IR spectroscopy.

1987 ◽  
pp. 1573-1579 ◽  
Author(s):  
Hiroshi ICHIKAWA ◽  
Haruo TERANISHI ◽  
Toshikatsu ISHIKAWA
Keyword(s):  
Ir Spectroscopy ◽  
Formation Mechanism

Cycloalkylidenselenoketene durch Pyrolyse von 1,2,3-Selenadiazolen — Untersuchungen mit der temperaturabhängigen PE-Spektroskopie und Matrix-IR-Spektroskopie [1]

1984 ◽  
Vol 39 (11) ◽  
pp. 1536-1540 ◽  
Author(s):  
Reinhard Schulz ◽  
Armin Schweig
Keyword(s):  
Liquid Phase ◽  
Ir Spectroscopy ◽  
Ir Spectra ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Variable Temperature ◽  
Matrix Ir Spectroscopy

Abstract The gas-phase pyrolysis of cyclohexeno-1,2,3-selenadiazole and cycloocteno-1,2,3-selenadiazole has been investigated by variable temperature photoelectron spectroscopy and matrix IR spectroscopy. The ring contracted, highly reactive products cyclopentylidenselenoketene (cyclopentylidenmethanselone) and cycloheptylidenselenoketene (cycloheptylidenmethanselone) - which had not been found in liquid phase thermolysis experiments - have been detected. Additionally HeI photoelectron and IR spectra of analogous ketenes and thioketenes are presented for comparative reasons.

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