Liaison hydrogène des arylamines : compétition des sites π et N

2004 ◽  
Vol 82 (9) ◽  
pp. 1413-1422 ◽  
Author(s):  
Eric Marquis ◽  
Jérôme Graton ◽  
Michel Berthelot ◽  
Aurélien Planchat ◽  
Christian Laurence
Keyword(s):  
Hydrogen Bonding ◽  
Lone Pair ◽  
Molecular Electrostatic Potentials ◽  
Hydrogen Bond Donor ◽  
Complexation Constant ◽  
Steric Factors ◽  
Troger's Base ◽  
Nitrogen Lone Pair ◽  
Ir Study ◽  
Hydrogen Bonded

An IR study, in the region of OH stretching, of a reference hydrogen-bond donor, 4-fluorophenol, hydrogen bonded to primary, secondary, and tertiary arylamines differently substituted on the ring and on the nitrogen, shows the formation of two kinds of 1:1 complexes in CCl4 solution: an OH···π and an OH···N hydrogen-bonded complex. The IR method gives only access to a global complexation constant Kt. A method is proposed for separating Kt into a Kπ component for hydrogen bonding to the π system and a KN component for hydrogen bonding to the nitrogen atom. This method is validated by comparing the estimated Kπ and KN values to theoretically calculated descriptors of basicity: the nitrogen lone pair orientation towards the aromatic ring, the molecular electrostatic potentials around the nitrogen and the π cloud, and the enthalpy of hydrogen bonding of hydrogen fluoride with the π system of selected arylamines. The main electronic and steric factors governing the competition between π and N sites are analysed. The strongest π and N bases among the arylamines are julolidine and Tröger's base, respectively. Triphenylamine and diphenylamine, which are nitrogen Brønsted bases, become π bases in hydrogen bonding. Moreover, there is no correlation between the pKHB and the pKBH+ scales of basicity of arylamines. The use of the pKBH+ scale is therefore not recommended in hydrogen-bonding studies.Key words: hydrogen bonding, arylamines, pKHB scale, competition of π and N hydrogen-bonded sites.

L'échelle pKHB de basicité de liaison hydrogène des amines tertiaires aliphatiques

2002 ◽  
Vol 80 (10) ◽  
pp. 1375-1385 ◽  
Author(s):  
Jérôme Graton ◽  
François Besseau ◽  
Michel Berthelot ◽  
Ewa D Raczynska ◽  
Christian Laurence
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Amino Nitrogen ◽  
Lone Pair ◽  
Steric Effects ◽  
Tertiary Amines ◽  
Complexation Constant ◽  
Hydrogen Bond Acceptor ◽  
Nitrogen Lone Pair ◽  
Hydrogen Bond Basicity

The hydrogen bond acceptor strength of 40 tertiary amines has been measured by Fourier transform – infrared (FTIR) spectrometry from their 1:1 complexation constant towards 4-fluorophenol in CCl4 at 25°C (the pKHB scale). Also measured was the frequency shift, Δν(OH), of the ν(OH) band of methanol hydrogen-bonded to these amines. The comparison of the thermodynamic hydrogen bond basicity scale, pKHB, with the spectroscopic one, Δν(OH), and with the Brønsted pKa scale, points to the great sensitivity of pKHB to steric effects. The pKHB scale of tertiary amines extends from 2.71 for quinuclidine to –0.34 for N,N-diisopropyl-3-pentylamine. The main factors governing this important variation (17 kJ·mol–1 on the Gibbs energy scale) are the electron-withdrawing inductive effect and various kinds of steric effects (e.g., opening of the CNC angles and hindrance to OH fixation on the nitrogen lone pair). Infrared (IR) spectra show the attachment of 4-fluorophenol to the nitrile nitrogen of Me2NCH2C[Formula: see text]N and Me2NCH2CH2C[Formula: see text]N, to the oxygen of N-methylmorpholine, and to the π electrons of (HC[Formula: see text]CCH2)3N and (PhCH2)3N, in addition to the attachment to the amino nitrogen. In (PhCH2)3N, the electron-withdrawing effect of the three benzyl substituents and, mainly, the very important congestion of the nitrogen lone pair reduce the nitrogen hydrogen-bond basicity almost to nothing, so that tribenzylamine, a nitrogen Brønsted base, turns to a π base in hydrogen bonding. From this example, the large differences between the pKHB and pKa scales of organic bases are emphasized.Key words: basicity, hydrogen bonding, tertiary amines, pKHB scale.

scholarly journals The N-atom in [N(PR3)2]+ cations (R = Ph, Me) can act as electron donor for (pseudo) anti-electrostatic interactions

CrystEngComm ◽  
2015 ◽  
Vol 17 (20) ◽  
pp. 3768-3771 ◽  
Author(s):  
Antonio Bauzá ◽  
Antonio Frontera ◽  
Tiddo J. Mooibroek ◽  
Jan Reedijk
Keyword(s):  
Hydrogen Bonding ◽  
Electron Donor ◽  
Molecular Hydrogen ◽  
Electrostatic Interactions ◽  
Lone Pair ◽  
Dft Study ◽  
Nitrogen Lone Pair

A CSD analysis and DFT study reveal that the nitrogen lone-pair in [N(PPh3)2]+ is partially intact and involved in intramolecular hydrogen bonding.

Photoelectron studies on intramolecularly hydrogen-bonded systems. I. The photoelectron spectra of cis- and trans-2-aminocyclopentanol, and cis- and trans-2-(N,N-dimethylamino)cyclopentanol

1976 ◽  
Vol 54 (4) ◽  
pp. 642-646 ◽  
Author(s):  
R. S. Brown
Keyword(s):  
Hydrogen Bonding ◽  
Ionization Energy ◽  
Lone Pair ◽  
Intramolecular Hydrogen Bonding ◽  
Photoelectron Spectra ◽  
Hydrogen Bonded Systems ◽  
Intramolecular Hydrogen ◽  
Cis And Trans ◽  
Infrared Data ◽  
Hydrogen Bonded

The photoelectron spectra of cis- and trans-2-aminocyclopentanol and cis- and trans-2-(N,N,-dimethylamino)cyclopentanol have been recorded and interpreted. The cis isomers exhibit N lone pair ionizations at higher ionization energy, and O lone pair ionizations at lower ionization energy than their trans isomers.The results are most consistent with the existence and observation of intramolecular hydrogen-bonding in the cis isomers. Infrared data on these systems also show that the cis isomers exist in the intramolecularly hydrogen-bonded state.

N.M.R. spectra and stereochemistry of the bipyridyls. III. 2,2'-Bipyridyl and dimethyl derivatives, 3,3'- bipyridyl, and 4,4' - bipyridyl

1967 ◽  
Vol 20 (6) ◽  
pp. 1227 ◽  
Author(s):  
TM Spotswood ◽  
CI Tanzer
Keyword(s):  
Hydrogen Bonding ◽  
Electrostatic Field ◽  
Field Effect ◽  
Chemical Shifts ◽  
Lone Pair ◽  
Diamagnetic Anisotropy ◽  
Equal Importance ◽  
Nitrogen Lone Pair ◽  
Lone Pair Electrons ◽  
Derivatives Of

The analysis of the n.m.r, spectra of 2,2?-, 3,3?-, and 4,4?-bipyridyl and three dimethyl-2,2?-bipyridyls is reported and the factors determining the relative chemical shifts of the ring protons and methyl groups in several solvents are discussed. The diamagnetic anisotropy of the neighbouring ring and electrostatic field effect of the nitrogen lone pair electrons are shown to be of roughly equal importance for derivatives of 2,2?-bipyridyl except in hydrogen bonding solvents. Attenuation of the electrostatic field effect in polar, and particularly in hydrogen bonding solvents, is established for 4- picoline, and for the bipyridyls, and this effect is responsible for striking changes in the spectrum of 2,2?-bipyridyl in hydrogen bonding solvents. An approximate interplanar angle of 58� is derived for 3,3?- dimethyl-2,2?-bipyridyl, and 2,2?-bipyridyl and its 4,4?- and 5,5?- dimethyl derivatives appear to be trans coplanar in all solvents. 3,3?- Bipyridyl and 4,4?-bipyridyl are probably highly twisted in all solvents, or alternatively, behave as essentially free rotors. The predicted conformations are in good agreement with the electronic spectral data.

Hydrogen Bonding to Thiocyanate Anions: Statistical and Quantum-Chemical Analyses

1998 ◽  
Vol 54 (3) ◽  
pp. 316-319 ◽  
Author(s):  
J. P. M. Lommerse ◽  
J. C. Cole
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Statistical Analysis ◽  
Lone Pair ◽  
Unexpected Result ◽  
Acta Cryst ◽  
Energy Calculations ◽  
Acceptor Atom ◽  
Detailed Statistical Analysis ◽  
Nitrogen Lone Pair

A statistical analysis of entries from the CSD (Cambridge Structural Database) showed that the average hydrogen-bond geometry to the nitrogen acceptor atom of the thiocyanate anion was not collinear with respect to the molecular axis of the anion and so not collinear with the nitrogen lone pair [Tchertanov & Pascard (1996). Acta Cryst. B52, 685–690]. This somewhat unexpected result has been investigated further using theoretical energy calculations applying Intermolecular Perturbation Theory in combination with a more detailed statistical analysis of an appropriate CSD dataset. The energy calculations pointed to the formation of the strongest hydrogen bonds in the nitrogen lone-pair direction. The statistical analysis showed that this directionality occurs in cases where the N atom accepts one hydrogen bond only. The non-linear average hydrogen-bond geometry observed in the earlier study can be attributed to multiple hydrogen bonding to the N atom. In such cases, there is a shift away from the optimum orientation.

Taking the halogen bonding–hydrogen bonding competition one step further: complexes of difluoroiodomethane with trimethylphosphine, dimethyl sulfide and chloromethane

2017 ◽  
Vol 73 (2) ◽  
pp. 168-178 ◽  
Author(s):  
Yannick Geboes ◽  
Frank De Proft ◽  
Wouter A. Herrebout
Keyword(s):  
Hydrogen Bonding ◽  
Dimethyl Sulfide ◽  
Halogen Bonding ◽  
Hydrogen Bond Donor ◽  
Lewis Bases ◽  
One Step ◽  
Fourier Transform Ir ◽  
Binary Associations ◽  
Bonded Complexes ◽  
Hydrogen Bonded

To rationalize the driving factors in the competition of halogen bonding and hydrogen bonding, the complexes of the combined halogen-/hydrogen-bond donor difluoroiodomethane with the Lewis bases trimethylphosphine, dimethyl sulfide and chloromethane are studied. For all Lewis bases,ab initiocalculations lead to halogen- and hydrogen-bonded complexes. Fourier transform–IR experiments involving solutions of mixtures of difluoroiodomethane with trimethylphosphine(-d9) or dimethyl sulfide(-d6) in liquid krypton confirm the coexistence of a halogen-bonded and hydrogen-bonded complex. Also for solutions containing chloromethane, evidence of the formation of binary associations is found, but no definitive assignment of the multiple complex bands could be made. Using van't Hoff plots, the experimental complexation enthalpies for the halogen- and hydrogen-bonded complex of difluoroiodomethane with trimethylphosphine are determined to be −15.4 (4) and −10.5 (3) kJ mol−1, respectively, while for the halogen- and hydrogen-bonded complexes with dimethyl sulfide, the values are −11.3 (5) and −7.7 (6) kJ mol−1, respectively. The experimental observation that for both trimethylphospine and dimethyl sulfide the halogen-bonded complex is more stable than the hydrogen-bonded complex supports the finding that softer Lewis bases tend to favor iodine halogen bonding over hydrogen bonding.

NUCLEAR MAGNETIC RESONANCE MEASUREMENTS IN SOLUTIONS OF ACETYLACETONE: THE EFFECT OF SOLVENT INTERACTIONS ON THE TAUTOMERIC EQUILIBRIUM

1957 ◽  
Vol 35 (11) ◽  
pp. 1351-1365 ◽  
Author(s):  
L. W. Reeves
Keyword(s):  
Chemical Shifts ◽  
Lone Pair ◽  
Tautomeric Equilibrium ◽  
Keto Form ◽  
Solvent Interaction ◽  
Solvent Interactions ◽  
Tautomeric Forms ◽  
Interacting Systems ◽  
Nitrogen Lone Pair ◽  
Hydrogen Bonded

A modified assignment of the PMR signals in acetylacetone is confirmed. The changes in intensity of selected signals with temperature are used to calculate an enthalpy of conversion of 2700 ± 100 cal. between keto and enol forms in pure acetylacetone.Interactions, which perturb the equilibrium between the tautomeric forms in dilute solution by formation of solution complexes, are studied by observing dilution chemical shifts in various solvents. The ratio of keto to enol forms is estimated from measurements of signal intensities at several dilutions in each solvent. The deviations from the correlations of Bernstein and Powling (5) between solvent dielectric constant and molar volume, and the position of the tautomeric equilibrium in dilute solutions, have been used as a criterion of solvent interaction. They are consistent with the present measurements.Typical basic, acidic, amphoteric, and neutral solvents have been chosen to investigate possible types of interaction. Cyclohexane and acetic acid do not perturb the equilibrium by any interactions. Triethylamine forms a hydrogen bonded complex through the enolic—OH group and the nitrogen lone pair, thus converting acetylacetone completely to enol form. Pyrrole forms a weakly hydrogen bonded complex through the carbonyl oxygens of the keto form. Freezing diagrams in the interacting systems are consistent with the complexes suggested by the PMR measurements.

Rage Against Conformity: Ruthenium(ɪɪ) Bisterpyridine Complexes Respond to Crystal Engineering Instructions with Whelming Results

2017 ◽  
Vol 70 (5) ◽  
pp. 529 ◽  
Author(s):  
Hasti Iranmanesh ◽  
Kasun S. A. Arachchige ◽  
William A. Donald ◽  
Niamh Kyriacou ◽  
Chao Shen ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Single Crystal ◽  
Crystal Engineering ◽  
Intermolecular Hydrogen Bonding ◽  
Hydrogen Bond Donor ◽  
One Dimensional ◽  
X Ray ◽  
Hydrogen Bonded

Four heteroleptic ruthenium(ii) complexes of 4′-functionalised 2,2′:6′,2′′-terpyridine are reported, along with their solid-state single-crystal X-ray structures. The complexes feature complementary hydrogen-bond donor (phenol) and acceptor (pyridyl) groups designed to assemble into one-dimensional polymers. In one example, the system obeys the programmed instructions to form a one-dimensional, self-complementary hydrogen-bonded polymer. In one other example, a water-bridged hydrogen-bonded polymer is formed. In the remaining two structures, aryl–aryl interactions dominate the intermolecular interactions, and outweigh the contribution of intermolecular hydrogen bonding.

Hydrogen bonding between phenols and cyanides

1966 ◽  
Vol 291 (1427) ◽  
pp. 460-468 ◽  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbon Tetrachloride ◽  
Equilibrium Constants ◽  
Lone Pair ◽  
Frequency Shifts ◽  
Tertiary Butyl ◽  
Group Frequency ◽  
Steric Factors ◽  
Lone Pair Electrons

The association between phenols and cyanides, dissolved in carbon tetrachloride, has been measured. The shifts of the bonded OH group frequency have been determined for a range of cyanides, and correlated with the Taft inductive factors of the groups concerned. Equilibrium constants for the formation of the complexes have been determined and correlated with the frequency shifts. The influence of steric factors has been studied, and it has been found that tertiary butyl groups in the ortho positions of phenol restrict the formation of the hydrogen bond. In most cases, the C≡N group frequency is displaced to higher frequency when bonded to a phenol. This effect is unusual, and suggests that the bonding occurs through the lone pair electrons on the nitrogen atom. Some data on the widths of the association bands have been given.

Solid-state structure of a layered hydrogen-bonded salt: guanidinium 5-benzoyl-4-hydroxy-2-methoxybenzenesulfonate methanol solvate

1996 ◽  
Vol 52 (1) ◽  
pp. 209-214 ◽  
Author(s):  
V. A. Russell ◽  
M. D. Ward
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Lone Pair ◽  
Carbonyl Oxygen ◽  
Two Dimensional ◽  
State Structure ◽  
Hydroxyl Proton ◽  
Intramolecular Hydrogen ◽  
Oxygen Lone Pair ◽  
Hydrogen Bonded

Guanidinium 5-benzoyl-4-hydroxy-2-methoxybenzene-sulfonate methanol solvate [C(NH2)3 +.(C14H11O3)SO3 −.CH3OH] crystallizes into a layered structure containing a two-dimensional hydrogen-bonded network typical of guanidinium alkane- and arenesulfonates. All six guanidinium protons and six sulfonate oxygen lone-pair acceptors participate in hydrogen bonding to form nearly planar pseudohexagonal hydrogen-bonded sheets, which can be viewed as parallel connected hydrogen-bonded ribbons. The 5-benzoyl-4-hydroxy-2-methoxybenzene groups are oriented to the same side of each ribbon, but the orientation of these groups on adjacent ribbons alternates with respect to the hydrogen-bonded sheet. The planar sheets stack with interdigitation of the arene groups, resulting in a structure in which layers of 5-benzoyl-4-hydroxy-2-methoxybenzene groups are separated by ionic hydrogen-bonded sheets. Each methanol molecule forms a hydrogen bond to one of the sulfonate O atoms, resulting in this oxygen forming a total of three hydrogen bonds, and fills void volume between the interdigitated 5-benzoyl-4-hydroxy-2-methoxybenzene groups of neighboring sheets. The benzophenone hydroxyl proton forms an intramolecular hydrogen bond to the carbonyl oxygen.

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