Does the topological approach characterize the hydrogen bond?

Chemistry - A European Journal, 2010

Journal of The American Chemical Society, 1975

Hydrogen-bonded dimers involving first-and second-row hydrides have been studied theoretically with ab initio molecular orbital methods, using a 431G basis set. Certain generalizations about H-bonded dimers found in a previous stu-dyZa of first-row dimers (those involving "3, H20, and HF) are supported by this study; others require modification. In addition to studying the dependence of H-bond energy and properties on the row of the periodic table, we examine the dependence of H-bond energies on the "hybridization" of the electron donor, including HCN, H2C0, H2CS, HNC, and HCP as electron donors. We have also studied ionic H bonds, ''P" H bonds, and H-bonded trimers in an attempt to relate their properties to those of the more conventional H-bonded dimers. Can a C-H bond be an effective H-bond proton donor? We attempt to answer this question by examining the proton donor ability of CH4 and CHF3. Electrostatic potentials turn out to facilitate our understanding of H-bond energies and structures, being more useful than Mulliken populations in rationalizing H-bond energies. Finally we address ourselves to the question of predicting dimer H-bond energies from the monomers involved. Using a very simple algebraic model, we are able to predict the H-bond energy of a total 144 H-bonded complexes, using as a basis our theorctical calculations on 25 complexes.

Journal of Molecular Structure, 1976

INDO localized molecular orbitals (LMO's) are utilized for investigating the nature of intermolecular hydrogen bonding in the fully geometry optimized dimers (HFh, (Hz0)2, (NH3)2, FH-OH 2 , HOH-FH, FH-NH 3 , H 2 NH-FH, H20-HNH2, HOH-NH3, HCN-HF, and HzCO-HF. The results suggest that a reasonable measure of relative hydrogen bond strengths should be the intra bond, two-center, one-electron interference energy connecting the acceptor atom and donated proton. This approach views the net stabilization energy of a hydrogen bonded dimer as arising from a large energy decrease due to formation of the hydrogen bond, modified by smaller energy increases due to internal decreases in monomer bond energies upon formation of the dimer. Hydrogen bond stabilization app.ears to be closely related to the extent of charge transfer within the hydrogen bonded complex. The calculated transfer of charge can largely be explained in terms of electron density shifts within the acceptor lone pairs, while the decrease in electron density on the proton is discussed in terms of the donor XH bond. The approach presented should be particularly useful for analyzing intramolecular hydrogen bonding systems where the hydrogen bond energy is not simply obtainable from monomer-dimer energy differences.

Canadian Journal of Chemistry, 2018

Herein, we present a novel study of hydrogen bonding using the localized pair model. Using localized molecular orbitals, we examine how the two localized electron pairs involved in hydrogen bonding change upon the formation of the interaction, as well as while the distance between the two species within the complex change. This is achieved through the use of extracule densities, which describe the probability associated with the centre of mass of an electron pair. Quantitative assessments are performed by analyzing the extracule density demonstrating that this method is on par with other density-based tools for the analysis of hydrogen bonds and their strengths.

Physical Chemistry Chemical Physics, 2014

Table 1 QTAIM parameters (electron density (ρHBCP), Laplacian (∇ 2 ρHBCP), kinetic electron energy density (GHBCP), potential electron energy density (VHBCP) and the total electron energy density (HHBCP) at the hydrogen bond critical point), hydrogen bond donor charge (QX-H) and the interaction energy calculated with the counterpoise procedure (∆ECP) changes for the HF• • • HF complex in the presence of the confining potential of cylindrical symmetry. All calculations have been performed using 6-311++G(2df,2pd) basis set. The results are based on the geometry optimized in vacuum (ω=0.0). All parameters except ∆ECP , which is in kcal/mol, are given in atomic units. M06-2X ω ρHBCP ∇ 2 ρHBCP GHBCP VHBCP HHBCP QX-H ∆E CP 0.00

Molecular Simulation, 2014

2014): Quantum chemical topological analysis of hydrogen bonding in HX…HX and CH 3 X…HX dimers (X = Br, Cl, F), Molecular Simulation, We present a systematic investigation of the nature and strength of the hydrogen bonding in HX···HX and CH 3 X· · ·HX (X ¼ Br, Cl and F) dimers using ab initio MP2/aug-cc-pVTZ calculations in the framework of the quantum theory of atoms in molecules (QTAIM) and electron localisation functions (ELFs) methods. The electron density of the complexes has been characterised, and the hydrogen bonding energy, as well as the QTAIM and ELF parameters, is consistent, providing deep insight into the origin of the hydrogen bonding in these complexes. It was found that in both linear and angular HX· · ·HX and CH 3 X· · ·HX dimers, F atoms form stronger HB than Br and Cl, but they need short (, 2 Å ) X· · ·HX contacts.

Chemical Physics, 2009

Individual hydrogen bond (HB) energies have been estimated in several systems involving multiple HBs such as adenine-thymine and guanine-cytosine using electron charge densities calculated at XÁ Á ÁH hydrogen bond critical points (HBCPs) by atoms in molecules (AIM) method at B3LYP/6-311++G ** and MP2/6-311++G ** levels. A symmetrical system with two identical H bonds has been selected to search for simple relations between q HBCP and individual E HB . Correlation coefficient between E HB and q HBCP in the base of linear, quadratic, and exponential equations are acceptable and equal to 0.95. The estimated individual binding energies E HB are in good agreement with the results of atom-replacement approach and natural bond orbital analysis (NBO). The E HB values estimated from q values at HÁ Á ÁX BCP are in satisfactory agreement with the main geometrical parameter HÁ Á ÁX. With respect to the obtained individual binding energies, the strength of a HB depends on the substituent and the cooperative effects of other HBs.

2003

Delocalization indices, as defined in the atoms in molecules theory, have been calculated between hydrogen-bonded atoms in 20 molecular complexes that are formed between several H-donor and acceptor molecules. In general, the delocalization index associated to an intermolecular hydrogen bond depends on the interaction energy of the complex, but also on the nature of the H-donor and acceptor atoms.

Structural Chemistry, 2005

The topological analysis of the electron localization function, (ELF) provides a convenient mathematical framework enabling an unambiguous characterization of bonds, and more particularly in terms of bond types. In this communication we present an overview of the application of this approach to hydrogen bonding in which we attempt to answer the following questions: 1. What is the ELF based topological definition of the hydrogen bond? 2. Is a hydrogen bonded complex a molecule or an assembly of molecules? 3. Is there a topological descriptor of the hydrogen bond strength? 4. Is it possible to provide a sub-classification of hydrogen bonds? 5. Is the topological approach predictive of the structure of the complex?

Journal of Molecular Structure, 1975

The Journal of Physical Chemistry A, 1997

A theoretical study of the linear and multiple approximation in a series of complexes formed by molecules with electron-rich hydrogen atoms has been carried out. The interaction energy (taking into account the zero-point energy and the basis set superposition error), the atomic charges, and the electron density of the monomers and complexes have been evaluated at the MP2/6-311++G** level. The linear complexes, which show a strong similarity to the standard hydrogen bonds except for the reverse direction of the electron transfer, could be defined as inverse hydrogen bonds.

Chemistry (Weinheim an der Bergstrasse, Germany), 2016

A theoretical study on some carboxylic acid dimers formed by positively or negatively charged molecules has been carried out by using DFT methods. The resulting dimers possess either a charge of +2 or -2. In addition, the corresponding neutral complexes have also been considered. The electron density distribution described by the atoms in molecules and the natural bond orbital methods, as well as the electric field maps of the systems, have been analyzed and compared without finding significant differences between the neutral and ionic complexes. The interaction energy along the dissociation path of the charged dimers shows both a local minimum and a local maximum, defining a stability region between them. When this energetic profile is recalculated by removing the repulsion between the charged groups, it resembles to those of the neutral molecules. Hence, the characteristics of the charged dimers are similar to those of the neutral ones: the addition of a repulsion term for the cha...

Chemical physics, 1998

. Ž . Density functional theory DFT calculations with B3LYP exchange-correlation functional and using 6-31 qqG d,p Ž . basis functions have been performed on weakly bound hydrogen bonded complexes between HX X s F,Cl and alkenes and Ž . alkynes, such as C H , C HX X s H,F,Cl , C H and allene. Calculations have also been carried out at MP2 s full level 2 4 2 4 2 of theory and using the same basis set as mentioned above for comparison with the DFT results. It has been observed that the BSSE uncorrected binding energies obtained from the B3LYP calculations are always lower than the corresponding MP2 results whereas opposite trend has been observed after BSSE correction. Hydrogen bond lengths obtained from MP2 and B3LYP calculations differ insignificantly. The H-X frequency shift due to complex formation has been well reproduced by the B3LYP method. q 1998 Elsevier Science B.V. All rights reserved. 0301-0104r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII: S 0 3 0 1 -0 1 0 4 9 8 0 0 1 1 1 -6

Pure and Applied …, 2011

1Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India; 2Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India; 330 Kimberley Road, Chesterton, Cambridge, CB4 1HH, UK; 4Department ...

Physical chemistry chemical physics : PCCP, 2015

Agostic bonding is of paramount importance in C-H bond activation processes. The reactivity of the σ C-H bond thus activated will depend on the nature of the metallic center, the nature of the ligand involved in the interaction and co-ligands, as well as on geometric parameters. Because of their importance in organometallic chemistry, a qualitative classification of agostic bonding could be very much helpful. Herein we propose descriptors of the agostic character of bonding based on the electron localization function (ELF) and Quantum Theory of Atoms in Molecules (QTAIM) topological analysis. A set of 31 metallic complexes taken, or derived, from the literature was chosen to illustrate our methodology. First, some criteria should prove that an interaction between a metallic center and a σ X-H bond can indeed be described as "agostic" bonding. Then, the contribution of the metallic center in the protonated agostic basin, in the ELF topological description, may be used to ev...