Synthesis and Infrared Spectroscopic Investigation of Hydrogen-Bonded Complexes between 1,8-Bis(Dimethylamino)Naphthalene and 2,6-Dihydroxynaphthalene in 2:1 and 1:2 Ratios in the Crystalline forms and in Acetonitrile

2003 ◽  
Vol 2003 (7) ◽  
pp. 448-450 ◽  
Author(s):  
Moustafa M. Habeeb ◽  
Mohamed A. Kharaba
Keyword(s):  
Ir Spectra ◽  
Spectroscopic Investigation ◽  
The Other ◽  
Other Hand ◽  
Infrared Spectroscopic ◽  
Crystalline Forms ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Two hydrogen bonded complexes between 1,8- bis(dimethylamino) naphthalene (DMAN) and 2,6-dihydroxynaphthalene (DHN) in 2:1 and 1:2 ratios were synthesised and studied using FTIR the spectra of the solid 2:1 complex revealed incomplete protonation of DMAN with the appearance of two broad absorptions representing ν(NHN)+ and ν(OHN) in the ranges 700–400 and 1600–700 cm−1 respectively, while the 1:2 complex indicated the complete protonation of DMAN with the appearance of two broad absorptions representing ν(NHN)+ and ν(OHO-) in the ranges 700–400 and 1600–700 cm−1 respectively. On the other hand the IR spectra in acetonitrile indicated that the 1:2 complex is more stable than the 2:1 complex.

The Infrared Spectrum of Vulcanized Rubber and the Chemical Reaction between Rubber and Sulfur

1948 ◽  
Vol 21 (4) ◽  
pp. 799-800 ◽  
Author(s):  
N. Sheppard ◽  
G. B. M. Sutherland
Keyword(s):  
Infrared Spectrum ◽  
Physical Properties ◽  
Chemical Reaction ◽  
Spectroscopic Investigation ◽  
The Other ◽  
Characteristic Absorption ◽  
Vulcanized Rubber ◽  
Other Hand ◽  
Infrared Spectroscopic

Abstract In an earlier paper we described an infrared spectroscopic investigation of the vulcanization of rubber, and drew attention to a band at 10.4 µ (960 cm.−1) which appeared in the spectrum of both straight and accelerated vulcanization. We have investigated further this phenomenon, and find that the intensity of this band correlates well with the proportion of sulfur chemically incorporated, but not with the degree of vulcanization as reflected in the physical properties of the finished product. We were unable to explain this band in a convincing manner in terms of C—S linkages, but more recently have found a band in the same position (10.4 µ) and another at 11.2 µ (890 cm.−1) in certain thermally degraded rubbers. Since in this case the two new bands are obviously due, respectively, to the development of new CHR:CHR′ and CRR′:CH2 groups, it seemed probable that the 10.4 µ band might also be caused by new groupings of the former type. An investigation of the spectrum of an ebonite (in which the rubber-sulfur reaction has been carried to an extreme) confirmed this idea. In this spectrum, absorptions in the region of 6 µ showed that a considerable number of bonds remained, but the characteristic absorption at 12.0 µ arising from CRR′: CHR″groups in rubber had largely disappeared. On the other hand, the band at 10.4 µ (although shifted to slightly longer wave lengths) had increased greatly in intensity.

Polymorphs of phenazine hexacyanoferrate(II) hydrate: supramolecular isomerism in a 2D hydrogen-bonded network

2021 ◽  
Vol 77 (2) ◽  
pp. 211-218
Author(s):  
Ivica Cvrtila ◽  
Vladimir Stilinović
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
The Other ◽  
Two Dimensional ◽  
Structural Motifs ◽  
Supramolecular Isomerism ◽  
Other Hand ◽  
Π Stacking ◽  
Hydrogen Bonded

The crystal structures of two polymorphs of a phenazine hexacyanoferrate(II) salt/cocrystal, with the formula (Hphen)3[H2Fe(CN)6][H3Fe(CN)6]·2(phen)·2H2O, are reported. The polymorphs are comprised of (Hphen)2[H2Fe(CN)6] trimers and (Hphen)[(phen)2(H2O)2][H3Fe(CN)6] hexamers connected into two-dimensional (2D) hydrogen-bonded networks through strong hydrogen bonds between the [H2Fe(CN)6]2− and [H3Fe(CN)6]− anions. The layers are further connected by hydrogen bonds, as well as through π–π stacking of phenazine moieties. Aside from the identical 2D hydrogen-bonded networks, the two polymorphs share phenazine stacks comprising both protonated and neutral phenazine molecules. On the other hand, the polymorphs differ in the conformation, placement and orientation of the hydrogen-bonded trimers and hexamers within the hydrogen-bonded networks, which leads to different packing of the hydrogen-bonded layers, as well as to different hydrogen bonding between the layers. Thus, aside from an exceptional number of symmetry-independent units (nine in total), these two polymorphs show how robust structural motifs, such as charge-assisted hydrogen bonding or π-stacking, allow for different arrangements of the supramolecular units, resulting in polymorphism.

scholarly journals Effect of additional side groups on the vibrational frequencies of benzoquinone molecules

BIBECHANA ◽  
2016 ◽  
Vol 14 ◽  
pp. 66-76
Author(s):  
Nabin Kumar Raut ◽  
Hari Prasad Lamichhane
Keyword(s):  
Ir Spectra ◽  
Gas Phase ◽  
Vibrational Frequencies ◽  
The Other ◽  
Methyl Groups ◽  
Computational Investigation ◽  
Strongly Coupled ◽  
Solvent Phase ◽  
Other Hand

The present work enumerates detailed computational investigation into the IR spectra in gas phase and in solvent of 1, 4- Benzoquinone family (benzoquinone (BQ), duroquinone (DQ), plastoquinone (PQ), ubiquinone (UQ), and dimethoxy dimethyl benzoquinone (MQo)). In  the spectra of BQ, PQ, and DQ, we observed separate intense carbonyl (C=O) and C=C bands respectively around 1730 cm-1 (intense), 1645 cm-1 (weak). On the other hand, for UQ and MQo, three prominent bands around 1652, 1703, and 1733 cm-1 were observed, where two C=O modes were uncoupled but one of the carbonyl is strongly coupled with C=C vibrations. The additional methyl groups downshift the intense carbonyl bands and upshift C=C mode frequencies. The carbonyl modes further downshifted in the solvent phase calculation.BIBECHANA 14 (2017) 66-76

FT-IR Spectroscopic Study of 1,5-Pentanedithiol and 1,6-Hexanedithiol Adsorbed on NaA, CaA and NaY Zeolites

2005 ◽  
Vol 60 (8-9) ◽  
pp. 633-636 ◽  
Author(s):  
Nuri Öztürk ◽  
Çağrı Çırak ◽  
Semiha Bahçeli
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectra ◽  
Spectroscopic Study ◽  
The Other ◽  
Other Hand ◽  
Liquid Phases ◽  
Stretching Vibration ◽  
Ft Ir ◽  
Ir Spectroscopic ◽  
Nay Zeolites

The adsorption of 1,5-pentanedithiol (1,5-PDT) and 1,6-hexanedithiol (1,6-HDT) in liquid phases on NaA (or 4A-type), CaA (or 5A-type) and NaY zeolites has been studied by using infrared spectroscopy. From the IR spectra it is found that the peak positions of the symmetric as well as the antisymmetric modes of the methylene (CH2) groups are observed at almost the same band values for the title dithiolates adsorbed on the A-type and NaY zeolites. On the other hand, the weak SH stretching vibration, observed for all samples, can be attributed to the sulphure atoms of 1,5-PDT and 1,6-HDT coordinatively adsorbed on cationic sites of the zeolites.

Infrared spectroscopic studies of hydrogen-bonded complexes in cryogenic sulutions

1987 ◽  
Vol 112 (3) ◽  
pp. 379-386 ◽  
Author(s):  
T.A. Iskanderov ◽  
Ya.M. Kimel'fel'd ◽  
E.M. Smirnova
Keyword(s):  
Spectroscopic Studies ◽  
Infrared Spectroscopic ◽  
Bonded Complexes ◽  
Hydrogen Bonded
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