scholarly journals Proton Transfer Equilibria and Critical Behavior of H-Bonding

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
L. Sobczyk ◽  
B. Czarnik-Matusewicz ◽  
M. Rospenk ◽  
M. Obrzud

The aim of the present paper is an analysis of the hydrogen bond properties for the acid-base systems depending on the ability to the proton transfer in the formulation of the Brönsted approach. After definition of the proton transfer equilibrium expressed by using the equation log KPT=ξΔpKN, various examples of different physical properties, such as dipole moments, IR spectra, and nuclear magnetic resonances, are presented which correlate with the ΔpKN value. In such a way, a critical state of hydrogen bonding can be defined that corresponds to the potential of the proton motion for either single minimum or double minimum with low barrier. A particular attention in this paper found electronic spectra which have not been analysed so far and the quantitative analysis of the vibrational polarizability which can reach very high values of the order of electronic polarizability.

Author(s):  
Graham Smith ◽  
Urs D. Wermuth

In the structure of the brucinium salt of 4-aminophenylarsonic acid (p-arsanilic acid), systematically 2,3-dimethoxy-10-oxostrychnidinium 4-aminophenylarsonate tetrahydrate, (C23H27N2O4)[As(C6H7N)O2(OH)]·4H2O, the brucinium cations form the characteristic undulating and overlapping head-to-tail layered brucine substructures packed along [010]. The arsanilate anions and the water molecules of solvation are accommodated between the layers and are linked to them through a primary cation N—H...O(anion) hydrogen bond, as well as through water O—H...O hydrogen bonds to brucinium and arsanilate ions as well as bridging water O-atom acceptors, giving an overall three-dimensional network structure.


2013 ◽  
Vol 69 (10) ◽  
pp. 1164-1169 ◽  
Author(s):  
Balasubramanian Sridhar ◽  
Jagadeesh Babu Nanubolu ◽  
Krishnan Ravikumar

Lamotrigine, an antiepileptic drug, has been complexed with three aromatic carboxylic acids. All three compounds crystallize with the inclusion ofN,N-dimethylformamide (DMF) solvent,viz.lamotriginium [3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazin-2-ium] 4-iodobenzoateN,N-dimethylformamide monosolvate, C9H8Cl2N5+·C7H4IO2−·C3H7NO, (I), lamotriginium 4-methylbenzoateN,N-dimethylformamide monosolvate, C9H7Cl2N5+·C8H8O2−·C3H7NO, (II), and lamotriginium 3,5-dinitro-2-hydroxybenzoateN,N-dimethylformamide monosolvate, C9H8Cl2N5+·C7H3N2O7−·C3H7NO, (III). In all three structures, proton transfer takes place from the acid to the lamotrigine molecule. However, in (I) and (II), the acidic H atom is disordered over two sites and there is only partial transfer of the H atom from O to N. In (III), the corresponding H atom is ordered and complete proton transfer has occurred. Lamotrigine–lamotrigine, lamotrigine–acid and lamotrigine–solvent interactions are observed in all three structures and they thereby exhibit isostructurality. The DMF solvent extends the lamotrigine–lamotrigine dimers into a pseudo-quadruple hydrogen-bonding motif.


2008 ◽  
Vol 120 (6) ◽  
pp. 613-620 ◽  
Author(s):  
Reji Thomas ◽  
Shrinwantu Pal ◽  
Ayan Datta ◽  
Mariusz K. Marchewka ◽  
Henryk Ratajczak ◽  
...  

2008 ◽  
Vol 07 (06) ◽  
pp. 1171-1186 ◽  
Author(s):  
SALMA PARVEEN ◽  
SUBOJIT DAS ◽  
ASIT K. CHANDRA ◽  
THERESE ZEEGERS-HUYSKENS

Hydrogen bonding interactions between trimethylamine (TMA) and a series of para substituted phenols (X– C 6 H 4 OH , X = H , CH 3, NH 2, Cl , CN , and NO 2) are studied by using density functional theory with the hybrid B3LYP functional and the 6-31++G(d,p) basis set. Both electron donor and acceptor substituents (X) are chosen to study systematically the relation between the proton donor ability of the phenols and the strength of the OH … N hydrogen bond. The effect of hydrogen bonding on spectral and structural parameters and their inter relation are discussed. The natural bond orbital (NBO) analysis (occupation of σ* orbitals, hyperconjugative energies and atomic charges) is also carried out to elucidate the reason behind the spectral and structural changes due to hydrogen bond formation. Several correlations between hydrogen bond strength and bond properties are discussed.


1979 ◽  
Vol 44 (8) ◽  
pp. 2494-2506 ◽  
Author(s):  
Otto Exner ◽  
Jorga Smolíková ◽  
Václav Jehlička ◽  
Ahmad S. Shawali

Substituted 2-bromo-1-phenylglyoxal 2-phenylhydrazones IIIa-f exist in tetrachloromethane or benzene solutions prevailingly in E-configuration and in conformation A with an intramolecular hydrogen bond. The latter was evidenced by the N-H valence frequency at 3 290 cm-1 and by 1H NMR shifts with reference to derivatives without a carbonyl group - α-chlorobenzaldehyde phenylhydrazones V. From dipole moments of IIIa-d, measured in benzene solution, the contribution of the hydrogen bond (μH) was evaluated to 17 . 10-30 C m. This quantity is twice larger than in any other reported compound but the direction of the vector is as usual: approximately from H to N. In structurally similar derivatives of hydroxylamine, substituted 2-phenylglyoxylhydroximoyl chlorides IVa-d, no intramolecular hydrogen bond was detected; the dipole moments found were interpreted in terms of the Z-configuration and the prevailing conformation G.


2015 ◽  
Vol 177 ◽  
pp. 51-64 ◽  
Author(s):  
Elangannan Arunan ◽  
Devendra Mani

In this discussion, we show that a static definition of a ‘bond’ is not viable by looking at a few examples for both inter- and intra-molecular hydrogen bonding. This follows from our earlier work (Goswami and Arunan,Phys. Chem. Chem. Phys.2009,11, 8974) which showed a practical way to differentiate ‘hydrogen bonding’ from ‘van der Waals interaction’. We report results fromab initioand atoms in molecules theoretical calculations for a series of Rg⋯HX complexes (Rg = He/Ne/Ar and X = F/Cl/Br) and ethane-1,2-diol. Results for the Rg⋯HX/DX complexes show that Rg⋯DX could have a ‘deuterium bond’ even when Rg⋯HX is not ‘hydrogen bonded’, according to the practical criterion given by Goswami and Arunan. Results for ethane-1,2-diol show that an ‘intra-molecular hydrogen bond’ can appear during a normal mode vibration which is dominated by the O⋯O stretching, though a ‘bond’ is not found in the equilibrium structure. This dynamical ‘bond’ formation may nevertheless be important in ensuring the continuity of electron density across a molecule. In the former case, a vibration ‘breaks’ an existing bond and in the later case, a vibration leads to ‘bond’ formation. In both cases, the molecule/complex stays bound irrespective of what happens to this ‘hydrogen bond’. Both these cases push the borders on the recent IUPAC recommendation on hydrogen bonding (Arunanet al. Pure. Appl. Chem.2011,831637) and justify the inclusive nature of the definition.


2014 ◽  
Vol 50 (95) ◽  
pp. 15026-15029 ◽  
Author(s):  
Zhiyun Zhang ◽  
Yen-Hao Hsu ◽  
Yi-An Chen ◽  
Chi-Lin Chen ◽  
Tzu-Chieh Lin ◽  
...  

The six- and seven-membered ring pyrrole–pyridine hydrogen bonding systems are developed, which undergo excited-state intramolecular proton transfer with distinct reaction dynamics.


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