Conformational Stability of Tetrafluorohydrazine, N<sub>2</sub>F<sub>4</sub>

Durig, J. R.; Shen, Zhongnan

doi:10.1021/jp9700995

Cited by 9 publications

(2 citation statements)

References 20 publications

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“…The energy‐partitioning analysis of F 2 NNF 2 was carried out by using the gauche conformation of the molecule (Figure 4b) in order to compare the results with those for the hydrazine molecule, which has a gauche equilibrium geometry. A recent experimental study of the conformational stability of N 2 F 4 by Raman spectroscopy showed that the gauche and trans conformations are energetically nearly degenerate 49. The enthalpy difference was determined to be 0.197±0.017 kcal mol −1 with the trans conformer the most stable rotamer.…”

Section: Resultsmentioning

confidence: 96%

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

Kovács

Esterhuysen

Frenking

2005

Chemistry A European J

138

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The nature of the chemical bond in nonpolar molecules has been investigated by energy-partitioning analysis (EPA) of the ADF program using DFT calculations. The EPA divides the bonding interactions into three major components, that is, the repulsive Pauli term, quasiclassical electrostatic interactions, and orbital interactions. The electrostatic and orbital terms are used to define the nature of the chemical bond. It is shown that nonpolar bonds between main-group elements of the first and higher octal rows of the periodic system, which are prototypical covalent bonds, have large attractive contributions from classical electrostatic interactions, which may even be stronger than the attractive orbital interactions. Fragments of molecules with totally symmetrical electron-density distributions, like the nitrogen atoms in N(2), may strongly attract each other through classical electrostatic forces, which constitute 30.0 % of the total attractive interactions. The electrostatic attraction can be enhanced by anisotropic charge distribution of the valence electrons of the atoms that have local areas of (negative) charge concentration. It is shown that the use of atomic partial charges in the analysis of the nature of the interatomic interactions may be misleading because they do not reveal the topography of the electronic charge distribution. Besides dinitrogen, four groups of molecules have been studied. The attractive binding interactions in H(n)E-EH(n) (E=Li to F; n=0-3) have between 20.7 (E=F) and 58.4 % (E=Be) electrostatic character. The substitution of hydrogen by fluorine does not lead to significant changes in the nature of the binding interactions in F(n)E-EF(n) (E=Be to O). The electrostatic contributions to the attractive interactions in F(n)E-EF(n) are between 29.8 (E=O) and 55.3 % (E=Be). The fluorine substituents have a significant effect on the Pauli repulsion in the nitrogen and oxygen compounds. This explains why F(2)N-NF(2) has a much weaker bond than H(2)N-NH(2), whereas the interaction energy in FO-OF is much stronger than in HO-OH. The orbital interactions make larger contributions to the double bonds in HB=BH, H(2)C=CH(2), and HN=NH (between 59.9 % in B(2)H(2) and 65.4 % in N(2)H(2)) than to the corresponding single bonds in H(n)E-EH(n). The orbital term Delta E(orb) (72.4 %) makes an even greater contribution to the HC triple bond CH triple bond. The contribution of Delta E(orb) to the H(n)E=EH(n) bond increases and the relative contribution of the pi bonding decreases as E becomes more electronegative. The pi-bonding interactions in HC triple bond CH amount to 44.4 % of the total orbital interactions. The interaction energy in H(3)E-EH(3) (E=C to Pb) decreases monotonically as the element E becomes heavier. The electrostatic contributions to the E-E bond increases from E=C (41.4 %) to E=Sn (55.1 %) but then decreases when E=Pb (51.7 %). A true understanding of the strength and trends of the chemical bonds can only be achieved when the Pauli repulsion is considered. In an absolute sense the rep...

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Section: Resultsmentioning

confidence: 96%

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

Kovács

Esterhuysen

Frenking

2005

Chemistry A European J

138

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“…We have been interested in the conformational stability and/or barriers of internal rotation of organoamine molecules of general formula RNH 2 where R is CH 3 CH 2 −, (CH 3 ) 2 −, (CH 3 ) 2 CH−, c-C 3 H 5 −, , c-C 4 H 7 −, CH 3 CH 2 CH 2 −, c-C 3 H 5 CH 2 −, and substituted hydrazines. − For hydrazine, N 2 H 4 , − and tetramethylhydrazine, N 2 (CH 3 ) 4 , only the gauche conformer is stable whereas for tetrafluorohydrazine, N 2 F 4 , both the gauche and trans conformers are present in the fluid phases at ambient temperature with an enthalpy difference of 69 ± 6 cm -1 (0.83 ± 0.07 kJ/mol). This value of the enthalpy difference was obtained from variable-temperature FT-IR spectra of xenon solutions of N 2 F 4 .…”

Section: Introductionmentioning

confidence: 99%

Conformational Stability from Temperature-Dependent FT-IR Spectra of Liquid Xenon Solutions, ab Initio Calculations, and r₀ Parameters for Methylhydrazine^,

et al. 2002

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Variable-temperature (−55 to −100 °C) studies of the infrared spectra (3500−400 cm-1) of methylhydrazine, CH3NHNH2, dissolved in liquid xenon have been recorded. From these data the enthalpy difference has been determined to be 323 ± 30 cm-1 (3.86 ± 0.36 kJ/mol) with the inner conformer (methyl group staggered and between the two hydrogens of the NH2 group) the more stable rotamer. A complete vibrational assignment is presented for the inner conformer, and several of the fundamentals of the outer conformer have been assigned. These assignments are consistent with the predicted wavenumbers obtained from ab initio MP2/6-31G(d) calculations utilizing three scaling factors. The optimized geometries, conformational stabilities, harmonic force fields, infrared intensities, Raman activities, and depolarization ratios have been obtained from RHF/6-31G(d) and/or MP2/6-31G(d) ab initio calculations. Hybrid density functional theory (DFT) calculations to obtain the structural parameters and conformational stability by the B3LYP method were also carried out. These quantities are compared to the corresponding experimental quantities when appropriate. Additionally conformational stabilities and structural parameters have also been predicted from MP2 level calculations with full electron correlation with 6-311+G(d,p) and 6-311+G(2d,2p) basis sets. The r 0 structural parameters have been obtained from a combination of the previously reported microwave rotational constants and ab initio MP2/6-311+G(d,p) predicted parameters. The results are compared to some corresponding quantities for some similar molecules.

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Synthesis of a GaN Cage Compound with a Hydrazinetetraide Fragment, [NN]⁴⁻, Stabilised by Six Gallium Atoms

Uhl

Rezaeirad

Layh

et al. 2010

Chemistry A European J

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Conformational Stability of Tetrafluorohydrazine, N₂F₄

Cited by 9 publications

References 20 publications

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

Conformational Stability from Temperature-Dependent FT-IR Spectra of Liquid Xenon Solutions, ab Initio Calculations, and r₀ Parameters for Methylhydrazine^,

Synthesis of a GaN Cage Compound with a Hydrazinetetraide Fragment, [NN]⁴⁻, Stabilised by Six Gallium Atoms

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Conformational Stability of Tetrafluorohydrazine, N2F4

Cited by 9 publications

References 20 publications

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

The Nature of the Chemical Bond Revisited: An Energy‐Partitioning Analysis of Nonpolar Bonds

Conformational Stability from Temperature-Dependent FT-IR Spectra of Liquid Xenon Solutions, ab Initio Calculations, and r0 Parameters for Methylhydrazine,

Synthesis of a GaN Cage Compound with a Hydrazinetetraide Fragment, [NN]4−, Stabilised by Six Gallium Atoms

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Product

Resources

About

Conformational Stability of Tetrafluorohydrazine, N₂F₄

Conformational Stability from Temperature-Dependent FT-IR Spectra of Liquid Xenon Solutions, ab Initio Calculations, and r₀ Parameters for Methylhydrazine^,

Synthesis of a GaN Cage Compound with a Hydrazinetetraide Fragment, [NN]⁴⁻, Stabilised by Six Gallium Atoms