Investigating the Resonance in Nitric Acid and the Nitrate Anion Based on a Modern Bonding Analysis

2018 ◽  
Vol 71 (4) ◽  
pp. 227 ◽  
Author(s):  
Malte Fugel ◽  
Florian Kleemiss ◽  
Lorraine A. Malaspina ◽  
Rumpa Pal ◽  
Peter R. Spackman ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Double Bond ◽  
Theoretical Calculations ◽  
Valence Bond ◽  
Nbo Analysis ◽  
Nitrate Anion ◽  
Resonance Structures ◽  
Bonding Analysis ◽  
Experimental Electron Density ◽  
Bond Character

The nitrate anion, NO3−, is often regarded as a textbook example for the very fundamental concept of resonance. Usually, three equivalent resonance structures with one N–O double bond and two N–O single bonds are considered. Consequently, each of the three N–O bonds should have a partial double bond character. In this study, we analyse the resonance in NO3− in comparison with the related species HNO3 and FNO3 by applying a combination of the Quantum Theory of Atoms in Molecules (QTAIM), a natural bond orbital (NBO) analysis, the electron localizability indicator (ELI), and valence bond (VB) calculations. Despite the fundamental importance of nitrate salts and nitric acid for the environment, chemistry, and industry, a bonding analysis is absent from the literature so far. The classical resonance structures are clearly reflected by the bond analysis tools, but are not the only contributions to the bonding situation. The resonance in HNO3 and FNO3 is greatly perturbed by the hydrogen and fluorine atoms. In addition to theoretical calculations, experimental electron density and wave function refinements were carried out on a KNO3 crystal.

Theoretical insight into the role of urea in the hydrolysis reaction of NO2 as a source of HONO and aerosols

2018 ◽  
Vol 15 (6) ◽  
pp. 372 ◽  
Author(s):  
Shuang Lv ◽  
Feng-Yang Bai ◽  
Xiu-Mei Pan ◽  
Liang Zhao
Keyword(s):  
Nitric Acid ◽  
Energy Barrier ◽  
Computational Study ◽  
Theoretical Calculations ◽  
Nbo Analysis ◽  
Hydrolysis Reaction ◽  
Hydrogen Bond Interaction ◽  
Distribution Maps ◽  
Urea Nitrate

Environmental contextUrea is an important component of dissolved organic nitrogen in rainfall and aerosols, but the sources and the mechanisms of its production are not well understood. This computational study explores the effects of urea and water on the hydrolysis of NO2 and urea nitrate production. The results will aid our interpretation of the role of urea in the formation of atmospheric secondary nitrogen contaminants and aerosols. AbstractThe effects of urea on the hydrolysis reaction 2NO2 + mH2O (m = 1–3) have been investigated by theoretical calculations. The energy barrier (−2.67 kcal mol−1) of the urea-promoted reaction is lower than the naked reaction by 14.37 kcal mol−1. Urea also has a better catalytic effect on the reaction than methylamine and ammonia. Urea acts as a catalyst and proton transfer medium in this process, and the produced HONO may serve as a source of atmospheric nitrous acid. In addition, the subsequent reactions include clusters of nitrite, urea, and nitric acid. Then urea nitrate (UN), which is a typical HNO3 aerosol, can be formed in the subsequent reactions. The production of the acid-base complex (UN-2) is more favourable with an energy barrier of 0.10 kcal mol−1, which is 3.88 kcal mol−1 lower than that of the zwitterions NH2CONH3+NO3− (UN-1). The formation of zwitterions and the hydrolysis reaction are affected by humidity. The multi water-promoted hydrolysis reactions exhibit better thermodynamic stability when the humidity is increased. The extra water molecules act as solvent molecules to reduce the energy barrier. The natural bond orbital (NBO) analysis is employed to describe the donor-acceptor interactions of the complexes. The hydrogen bond interaction between the urea carbonyl and nitric acid of UN-2 is the strongest. The potential distribution maps of the urea nitrate and hydrate are examined, and the result shows that they tend to form zwitterions.

The E2C mechanism in elimination reactions. IX. Re-examination of the olefin-like transition-state

1983 ◽  
Vol 36 (9) ◽  
pp. 1667 ◽  
Author(s):  
DM Muir ◽  
AJ Parker
Keyword(s):  
Double Bond ◽  
Transition State ◽  
Valence Bond ◽  
Large Degree ◽  
Apparent Lack ◽  
Bond Model ◽  
Leaving Group ◽  
Elimination Reactions ◽  
Kinetics Of ◽  
Bond Character

The kinetics and product olefins arising from E2C-like elimination reactions of secondary bromides and tosylates having various alkyl and conjugating substituents at Cα and Cβ are re-examined in the light of the theoretical Pross-Shaik valence-bond model and the apparent lack of a β-phenyl effect. Comparison of the effect of substituents at Cα and Cβ shows that whilst there are differences in reactivity and products of E2C reactions there is also a large degree of double-bond character in the transition state. There is a good correlation between the kinetics of E2C reactions and the double-bond stabilization energy arising from both alkyl and conjugating substituents. Contributing valence-bond structures, giving asymmetry and partial charge at Cα and Cβ appear to vary in importance according to leaving group and substituent type.

Synthesis and properties of 1,3-bis(4-nitrophenyl)-1-butene

1980 ◽  
Vol 45 (7) ◽  
pp. 2120-2124 ◽  
Author(s):  
Gabriel Čík ◽  
Anton Blažej ◽  
Kamil Antoš ◽  
Igor Hrušovský
Keyword(s):  
Acetic Acid ◽  
Nitric Acid ◽  
Double Bond ◽  
Fuming Nitric Acid

1,3-Bis(4-nitrophenyl)-1-butene was prepared by nitration of 1,3-diphenyl-1-butene (I) with fuming nitric acid in acetic acid. The double bond in I was protected by addition of bromine which was eliminated after the nitration. The UV, IR and 1H- spectra of the synthesized compounds are interpreted.

scholarly journals Improvements in the profiles and distributions of nitric acid and nitrogen dioxide with the LIMS version 6 dataset

2010 ◽  
Vol 10 (10) ◽  
pp. 4741-4756 ◽  
Author(s):  
E. Remsberg ◽  
M. Natarajan ◽  
B. T. Marshall ◽  
L. L. Gordley ◽  
R. E. Thompson ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Nitrogen Dioxide ◽  
Theoretical Calculations ◽  
Spin Splitting ◽  
Oxides Of Nitrogen ◽  
Polar Night ◽  
Chemical Effects ◽  
Satellite Sensors ◽  
Precision And Accuracy

Abstract. The quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) nitric acid (HNO3) and nitrogen dioxide (NO2) profiles and distributions of 1978/1979 are described after their processing with an updated, Version 6 (V6) algorithm and subsequent archival in 2002. Estimates of the precision and accuracy of both of those species are developed and provided herein. The character of the V6 HNO3 profiles is relatively unchanged from that of the earlier LIMS Version 5 (V5) profiles, except in the upper stratosphere where the interfering effects of CO2 are accounted for better with V6. The accuracy of the retrieved V6 NO2 is also significantly better in the middle and upper stratosphere, due to improvements in its spectral line parameters and in the reduced biases for the accompanying V6 temperature and water vapor profiles. As a result of these important updates, there is better agreement with theoretical calculations for profiles of the HNO3/NO2 ratio, day-to-night NO2 ratio, and with estimates of the production of NO2 in the mesosphere and its descent to the upper stratosphere during polar night. In particular, the findings for middle and upper stratospheric NO2 should also be more compatible with those obtained from more recent satellite sensors because the effects of the spin-splitting of the NO2 lines are accounted for now with the LIMS V6 algorithm. The improved precisions and more frequent retrievals of the LIMS profiles along their orbit tracks provide for better continuity and detail in map analyses of these two species on pressure surfaces. It is judged that the chemical effects of the oxides of nitrogen on ozone can be studied quantitatively throughout the stratosphere with the LIMS V6 data.

scholarly journals Crystal structure ofN′′-benzyl-N′′-[3-(benzyldimethylazaniumyl)propyl]-N,N,N′,N′-tetramethylguanidinium bis(tetraphenylborate)

2015 ◽  
Vol 71 (12) ◽  
pp. o1086-o1087
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Positive Charge ◽  
Planar Geometry ◽  
Methyl Groups ◽  
Two Dimensional ◽  
Single Bond ◽  
Double Bond Character ◽  
Bond Lengths ◽  
Bond Character

In the crystal structure of the title salt, C24H38N42+·2C24H20B−, the C—N bond lengths in the central CN3unit of the guanidinium ion are 1.3364 (13), 1.3407 (13) and 1.3539 (13) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3plane. The bonds between the N atoms and the terminal methyl groups of the guanidinium moiety and the four C—N bonds to the central N atom of the (benzyldimethylazaniumyl)propyl group have single-bond character. In the crystal, C—H...π interactions between the guanidinium H atoms and the phenyl C atoms of the tetraphenylborate ions are present, leading to the formation of a two-dimensional supramolecular pattern parallel to theacplane.

scholarly journals 3-Phenyl-N,N,N′,N′-tetramethyl-1-ethyne-1-carboximidamidium bromide

2012 ◽  
Vol 68 (6) ◽  
pp. o1812-o1812 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Triple Bond ◽  
Positive Charge ◽  
Bond Distance ◽  
Double Bond Character ◽  
Acetylenic Bond ◽  
Compound C ◽  
Bond Character

The reaction of 3,3,3-tris(dimethylamino)-1-phenylprop-1-yne with bromine in pentane yields the title compound, C13H17N2 +·Br−. The acetylenic bond distance [1.197 (2) Å] is consistent with a C[triple-bond]C triple bond. The amidinium C=N bonds [1.325 (2) and 1.330 (2) Å] have double-bond character and the positive charge is delocalized between the two dimethylamino groups.

scholarly journals Reactions of Dihaloboranes with Electron-Rich 1,4-Bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadienes

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2875
Author(s):  
Li Ma ◽  
Xiaolin Zhang ◽  
Wenbo Ming ◽  
Shengxin Su ◽  
Xiaoyong Chang ◽  
...  
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
Diffraction Analysis ◽  
1H Nmr Spectroscopy ◽  
Variable Temperature ◽  
Organosilicon Compounds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multinuclear Nmr Spectroscopy ◽  
Bond Character

The reactions of electron-rich organosilicon compounds 1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (1), 2,3,5,6-tetramethyl-1,4-bis(trimethylsilyl)-1,4-diaza-2,5-cyclohexadiene (2), and 1,1′-bis(trimethylsilyl)-1,1′-dihydro-4,4′-bipyridine (12) with B-amino and B-aryl dihaloboranes afforded a series of novel B=N-bond-containing compounds 3–11 and 13. The B=N rotational barriers of 7 (>71.56 kJ/mol), 10 (58.79 kJ/mol), and 13 (58.65 kJ/mol) were determined by variable-temperature 1H-NMR spectroscopy, thus reflecting different degrees of B=N double bond character in the corresponding compounds. In addition, ring external olefin isomers 11 were obtained by a reaction between 2 and DurBBr2. All obtained B=N-containing products were characterized by multinuclear NMR spectroscopy. Compounds 5, 9, 10a, 11, and 13a were also characterized by single-crystal X-ray diffraction analysis.

THE SOLVOLYSIS OF THE ALPHA- AND BETA-3,4,6-TRI-O-ACETYL-D-GLUCOPYRANOSYL CHLORIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 128-133 ◽  
Author(s):  
R. U. Lemieux ◽  
G. Huber
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Positive Charge ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Double Bond Character ◽  
Ionic Reactions ◽  
Oxygen Bond ◽  
Bond Character ◽  
Anomeric Center

3,4,6-Tri-O-acetyl-β-D-glucopyranosyl chloride was found to undergo solvolysis in acetic acid to form 1,3,4,6-tetra-O-acetyl-α-D-glucopyranose as the main reaction product. The much less reactive anomeric α-chloride also appeared to undergo solvolysis with extensive inversion of the anomeric center. It is submitted that the tendencies for inversion obtained in these ionic reactions are due to the conformations imposed on the intermediate ions through distribution of the positive charge to the ring oxygen and the consequent introduction of double-bond character to the carbon-1 to ring-oxygen bond.

13C Isotopic Effect on the Raman Spectrum and Structure of C60 Fullerene

1994 ◽  
Vol 359 ◽  
Author(s):  
Pham V. Huong ◽  
Denis JÉrÔme ◽  
Pascale Auban-Senzier ◽  
Patrick Bernier
Keyword(s):  
Raman Spectrum ◽  
Double Bond ◽  
Frequency Shift ◽  
Organic Compounds ◽  
Isotopic Effect ◽  
Experimental Result ◽  
C60 Fullerene ◽  
Strongly Coupled ◽  
Stretching Vibration ◽  
Bond Character

ABSTRACTThe Raman spectrum of 13C enriched C60 samples is recorded and analyzed in comparison with that of undoped 12C60. Comparison with the isotopic effect in diamond and in other infinite solid networks is also made.A frequency shift depending on the amount of 13C is observed for the C=C stretching vibration, without any splitting. This effect is unusual and is a proof that the C=C is not localized and its double bond character is not isolated but strongly coupled with other bonds in the cage. If the CC bond was independent as in small or non-spherical molecules such as organic compounds, an isotopic effect of Δv ≃ 30 cm-1 for 12C=13C and Δv ≃ 60 cm−1 for 13C=13C could be expected and a splitting could appear in the case of uncompleted 13C substitution and variable relative intensities could be observed. It is not the case of 13C60.In isotopic C60, all C=C vibrations in the spherical network are stronglycoupled ; an average isotopic mass must be considered for the randomly distributed isotopic atoms in the material to interpret the experimental result. C60 has thus more solid than molecule behavior.

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