Geometric correlations and infrared spectrum of adenine–uracil hydrogen bonds in CDCl3 solution

2010 ◽  
Vol 12 (48) ◽  
pp. 15695 ◽  
Author(s):  
Yun-an Yan ◽  
Oliver Kühn
2014 ◽  
Vol 541-542 ◽  
pp. 343-348
Author(s):  
Xiu Jie Jia ◽  
Jian Feng Li ◽  
Fang Yi Li

Biomass cushioning packaging material has been gaining attention in the properties of the materials because of biodegradable and green environmental protection, and the starch plastics play an important role. Urea, formamide, glycerol, ethylene glycol four material compounded with starch respectively, for the purpose to forming hydrogen bonds by the test in this paper, the ability to hydrogen bond with the starch has been observed by infrared spectrum analysis. The results showed that urea, formamide as strong electronegative group stronger binding, glycerol and ethylene glycol are more preferably to form hydrogen bonds with the starch because of more hydroxyl group content.


1963 ◽  
Vol 41 (6) ◽  
pp. 1477-1484 ◽  
Author(s):  
J. P. Guertin ◽  
M. Onyszchuk

Silicon tetrafluoride reacts with methanol in a 1:4 mole ratio, forming the complex SiF4.4CH3OH, which freezes to a glass at about −20° and is completely dissociated in the gaseous phase at 25°. Conductivity measurements show clearly that it is a very weak electrolyte in methanol solution. Its infrared spectrum does not contain an Si—O bond stretching absorption band. Proton magnetic resonance measurements provide strong evidence of hydrogen bonding between silicon tetrafluoride and methanol. These results indicate that the structure of the complex requires tetracovalent rather than hexacovalent silicon and strong hydrogen bonds between methanol and each of the four fluorine atoms.


1972 ◽  
Vol 50 (21) ◽  
pp. 3443-3449 ◽  
Author(s):  
J. E. Bertie ◽  
D. A. Othen

The infrared spectra of authenticated samples of ethylene oxide hydrate and deuterate at 100 °K have been measured between 360 and 20 cm−1. The spectra confirm that the water molecules are orientationally-disordered and reorient slowly compared to far-infrared frequencies. An empirical correlation is suggested between the frequencies of strong absorption and the number of non-equivalent hydrogen bonds, their length and distribution. The contribution to the spectrum by the ethylene oxide intermolecular vibrations is discussed.


2014 ◽  
Vol 16 (45) ◽  
pp. 24685-24690 ◽  
Author(s):  
Nicolai Bork ◽  
Ville Loukonen ◽  
Henrik G. Kjaergaard ◽  
Hanna Vehkamäki

Molecular dynamics simulations reveal that the asymmetric peak seen in IR spectra of acetonitrile–HCl molecular complexes are due to high population of complexes with partially broken hydrogen bonds.


1972 ◽  
Vol 26 (6) ◽  
pp. 599-605 ◽  
Author(s):  
Deepali Sinha ◽  
J. E. Katon

The complete vibrational spectra of cyanoacetic acid and sodium cyanoacetate have been recorded. A tentative vibrational assignment for both molecules is proposed. The results appear to be most consistent with a hydrogen-bonded polymer structure of cyanoacetic acid. The marked effect of temperature on the infrared spectrum of the acid has been explained in terms of an order-disorder transition involving the position of the hydrogen atoms forming the hydrogen bonds in the crystal.


1977 ◽  
Vol 30 (12) ◽  
pp. 2591 ◽  
Author(s):  
SD Hamann ◽  
E Spinner

The infrared spectra of the title compounds have been measured over the pressure range 0-42 kbar at 25�C. The phase change at c. 12 kbar is accompanied by an increase in the NH stretching frequencies and other well-defined spectral changes. Vibrational coupling in phase II of HCO2NH4 between CH in-plane bending in HCO2- and a bending motion in NH4+, and its counterpart for DCO2ND4, account for some unusual frequency changes arising from isotopic substitution in the counter ion. The spectral changes suggest that during the phase change I → II the NH...O hydrogen bonds are weakened and the cations move to positions in close proximity beside the CH bonds.


1960 ◽  
Vol 38 (1) ◽  
pp. 34-44 ◽  
Author(s):  
C. Brissette ◽  
C. Sandorfy

The infrared spectra of a number of amine hydrohalides have been measured in the lithium fluoride region.Hydrogen bonding and the torsional oscillations of the [Formula: see text] groups influence these spectra characteristically. The [Formula: see text] stretching frequencies give broad or fairly broadbands. They are near 3000 cm−1 for aliphatic primary amine salts. The corresponding band lies at somewhat lower frequencies for secondary amine salts and much lower for tertiary ones. The aromatic amine hydrohalides exhibit these bands at lower frequencies than do the aliphatic amine salts of the same order. There is a shift to higher frequencies in the series hydrochloride, hydrobromide, hydriodide.All these spectra contain a number of sharper bands which may or may not coincide with the hydrogen-bonded stretching bands. These are combination bands involving mainly deformation vibrations, and they shift to lower frequencies, throughout the series hydrochloride, hydrobromide, hydriodide.The importance of electrical anharmonicity for the appearance of these bands is stressed.The hydrogen bonds in amine hydrohalides appear to be largely electrostatic in character.


2011 ◽  
Vol 391-392 ◽  
pp. 912-916
Author(s):  
Jun Li Ren ◽  
Xin Wen Peng ◽  
Run Cang Sun ◽  
Hua Yu Qiu

A novel cationic gelatin graft copolymer was developed by the graft copolymerization reaction of gelatin with acrylamide (AM) and methacryloyloxyethyl trimethylammonium chloride (DMC) in this paper. The structure of graft copolymer was analyzed briefly by the analysis of infrared spectrum, and it was found that monomers (AM and DMC) actually were grafted onto the backbone of gelatin. The effect of reaction conditions such as the weight ratios of AM/gelatin or AM/DMC on grafting parameters and the application of the cationic graft copolymer as the dry strength agent in papermaking were investigated. Experiments showed that a graft copolymer with high the percent grafting and the grafting efficiency could be obtained by controlling the AM/gelatin weight ratio and AM/DMC weight ratio. The application test showed that the results obtained from the physical intensities of handsheets under the treatment of the grafted gelatin [gel-g-P(AM-co-DMC)] were great better than the control sample, which was due to the hydrogen bonds and ionic bonds among fibres in pulp and cationic graft copolymer.


1993 ◽  
Vol 71 (4) ◽  
pp. 549-560 ◽  
Author(s):  
Jacques Poitras ◽  
Martin Leduc ◽  
André L. Beauchamp

Dark-red crystals of (H2aza)5[Cu5Cl14(H2O)4]Cl were obtained by addition of HCl to equimolar amounts of 7-azaindole (Haza) and CuCl2•2H2O in methanol. They were shown by X-ray diffraction (triclinic, [Formula: see text] a = 9.396(1), b = 9.894(1), c = 15.958(1), Å, α = 106.10(1)°, β = 98.25(1)°, γ = 105.56(1)°, Z = 1, R = 0.031) to contain infinite chains in which the basic [Cu5Cl14(H2O)4]4− pattern is built up from trans-CuCl2(H2O)2, [CuCl3(H2O)]−, and dichlorobridged [Cu2Cl6]2− species. In the idealized chain, these units occur in the 1:2:1 ratio, but disorder is present and some of the CuCl2(H2O)2 units are randomly replaced by [CuCl3(H2O)]−. The Cu atoms have a roughly square-planar primary coordination, and connection along the chain is achieved by weaker apical Cu–Cl bridging interactions. All azaindole molecules are present as uncoordinated N7-protonated monocations. A related (H2aza)3[Cu3Cl8(H2O)3]Cl salt was obtained as a side-product of the reaction of 7-azaindole with excess CuCl2•2H2O in methanol without acid. In these brown crystals (triclinic, [Formula: see text] a = 9.308(1), b = 9.964(1), c = 19.212(4) Å, α = 76.67(1)°, β = 79.35(1)°, γ = 75.27(1)°, Z = 2, R = 0.046), the [Cu6Cl16(H2O)6]4− pattern of the chain contains the same three building units as above, but in the 2:2:1 ratio. In both salts, the polymeric chloro-copper chains are parallel and separated by azaindolium cations stacked along the same direction. The structures are stabilized by networks of hydrogen bonds involving the azaindolium cations, the chlorine atoms, and water molecules in the chloro-copper chain, and a noncoordinated Cl− ion. Most of the azaindolium cations are disordered. The influence of N7-protonation on the infrared spectrum of azaindole is discussed.


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