The covalence and infrared spectra of cationic hydrogen bonds and dihydrogen bonds

2014 ◽  
Vol 13 (07) ◽  
pp. 1450060 ◽  
Author(s):  
Boaz G. Oliveira
Keyword(s):  
Hydrogen Bonds ◽  
Bond Length ◽  
Infrared Spectra ◽  
Theoretical Study ◽  
Interaction Strength ◽  
Covalent Character ◽  
Frequency Shifts ◽  
Dihydrogen Bonds ◽  
Length Reduction ◽  
Ethyl Cation

A theoretical study of hydrogen bonds and dihydrogen bonds formed by ethyl cation, hydrocarbons and magnesium hydride is presented with calculations performed at the BHandHLYP/6-31G(d,p) level of theory. The structural results and IR analyses demonstrated great insights, mainly the strengthening and weakness of the CC bond of the ethyl cation and π or pseudo-π bonds, respectively. The interaction strength was measured through the supermolecule as well as by means of additional approaches. The QTAIM calculations were applied to characterize not only the intermolecular interactions but specifically the covalent character in the H + ⋯ π, H + ⋯ pseudo-π and H + ⋯ H contacts. The NBO calculations were useful to interpret the polarization on the CC bond and whether this effect is related with the bond length reduction as well as increase of charge density and frequency shifts.

scholarly journals The formation of hydride bonds in cationic complexes of nBeH2•••mX with n=1 or 2, m=1 or 2 and X = Li+ or Na+

2014 ◽  
Vol 79 (11) ◽  
pp. 1413-1420
Author(s):  
Boaz Oliveira
Keyword(s):  
Charge Density ◽  
Intermolecular Interaction ◽  
Infrared Spectra ◽  
Interaction Strength ◽  
Covalent Character ◽  
Topological Parameters ◽  
Density Concentration ◽  
Optimized Geometries

Through the BH and HLYP/6-31G(d,p) calculations, the optimized geometries and topological parameters of the BeH2???Na+, BeH2???Li+, 2BeH2???Na+, BeH2???2Na+, 2BeH2???Li+ and BeH2???2Li+ cationic complexes were obtained. One or two hydride bonds formed simultaneously on the same hydride center. The analysis of the infrared spectra revealed the existence of red-shifts and blue-shifts on the BeH bonds, whose effects are not in line with the intermolecular interaction strength determined by means of the supermolecule approach. The QTAIM calculations were developed to measure the charge density concentration on the H???Na+ and H???Li+ hydride bonds. Moreover, the covalent character of these interactions interpreted on the basis of the ratio between kinetic and potential electronic energies was also examined.

A SPECTROSCOPIC STUDY OF HYDROGEN BONDING IN PERFORMIC AND PERACETIC ACIDS

1952 ◽  
Vol 30 (11) ◽  
pp. 821-830 ◽  
Author(s):  
Paul A. Giguère ◽  
A. Weingartshofer Olmos
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Peracetic Acid ◽  
The Other ◽  
Frequency Shifts ◽  
Vapor State ◽  
Nonpolar Solvents ◽  
Intramolecular Hydrogen

The infrared spectra of concentrated performic and peracetic acids were measured in the rock-salt region. The most significant features are theO—H stretching frequency at 3310–3350 cm−1 and the OH bending frequency at 1450 cm−1 which, for both peracids, remain essentially the same in the vapor state as in the liquid or in solution in nonpolar solvents. This is attributed to intramolecular hydrogen bonds resulting in particularly stable five-membered rings,[Formula: see text]Steric conditions in the percarboxylic group are favourable to such ring formation or chelation. From the observed frequency shifts the energy of these hydrogen bonds is estimated to be about 7 kcal. per mole. No evidence for unchelated molecules was found even in very dilute solutions of peracetic acid in nonpolar solvent nor in the vapour at low pressure and moderate temperature. Tentative assignments of the other frequencies in the spectra of the peracids are made by comparison with those of formic and acetic acids.The danger involved in handling these peracids in concentrated form is emphasized.

Hydrogen bonds between phthalimide and hydrogen fluoride: A theoretical study

2011 ◽  
Vol 111 (7-8) ◽  
pp. 1387-1394 ◽  
Author(s):  
NatháLia B. de Lima ◽  
Victor H. Rusu ◽  
Mozart N. Ramos
Keyword(s):  
Hydrogen Bonds ◽  
Hydrogen Fluoride ◽  
Theoretical Study

scholarly journals Theoretical Study and X-ray Determination of Bianthrones:  Long C−C Bond Length and Preferred Gauche Conformation

2003 ◽  
Vol 68 (6) ◽  
pp. 2528-2528
Author(s):  
Pai-Chi Li ◽  
Tsung-Shing Wang ◽  
Gen-Hsian Lee ◽  
Yi-Hong Liu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Bond Length ◽  
Theoretical Study ◽  
Gauche Conformation ◽  
X Ray

Infrared spectra of the ammonium ion in crystals. Part VIII. Spectroscopic criteria of highly-bent hydrogen bonds

1980 ◽  
Vol 58 (9) ◽  
pp. 867-874 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Ammonium Ion ◽  
Temperature Transition ◽  
Increasing Temperature

Available evidence suggests that (1) the stretching frequencies of highly-bent hydrogen bonds decrease with increasing temperature, regardless of whether the bonds are static or dynamic in character, to a single acceptor or to several competing acceptors; and (2) departures from symmetric trifurcation (or bifurcation) toward asymmetric situations lower the stretching frequency. In further support of these criteria isotopic probe ion spectra between 10 K and room temperature have been obtained for taurine and for trigonal (NH4)2MF6 (M = Si, Ge, Sn, Ti). Evidence of a low-temperature transition at 100(10) K in trigonal (NH4)2SnF6 is presented, and existence of the previously reported transition at 38.6 K in trigonal (NH4)2SiF6 is confirmed. Symmetry changes associated with these transitions are discussed.

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