1
|
A QCT View of the Interplay between Hydrogen Bonds and Aromaticity in Small CHON Derivatives. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27186039. [PMID: 36144774 PMCID: PMC9504421 DOI: 10.3390/molecules27186039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/07/2022] [Accepted: 09/13/2022] [Indexed: 11/18/2022]
Abstract
The somewhat elusive concept of aromaticity plays an undeniable role in the chemical narrative, often being considered the principal cause of the unusual properties and stability exhibited by certain π skeletons. More recently, the concept of aromaticity has also been utilised to explain the modulation of the strength of non-covalent interactions (NCIs), such as hydrogen bonding (HB), paving the way towards the in silico prediction and design of tailor-made interacting systems. In this work, we try to shed light on this area by exploiting real space techniques, such as the Quantum Theory of Atoms in Molecules (QTAIM), the Interacting Quantum Atoms (IQA) approaches along with the electron delocalisation indicators Aromatic Fluctuation (FLU) and Multicenter (MCI) indices. The QTAIM and IQA methods have been proven capable of providing an unbiased and rigorous picture of NCIs in a wide variety of scenarios, whereas the FLU and MCI descriptors have been successfully exploited in the study of diverse aromatic and antiaromatic systems. We used a collection of simple archetypal examples of aromatic, non-aromatic and antiaromatic moieties within organic molecules to examine the changes in π delocalisation and aromaticity induced by the Aromaticity and Antiaromaticity Modulated Hydrogen Bonds (AMHB). We observed fundamental differences in the behaviour of systems containing the HB acceptor within and outside the ring, e.g., a destabilisation of the rings in the former as opposed to a stabilisation of the latter upon the formation of the corresponding molecular clusters. The results of this work provide a physically sound basis to rationalise the strengthening and weakening of AMHBs with respect to suitable non-cyclic non-aromatic references. We also found significant differences in the chemical bonding scenarios of aromatic and antiaromatic systems in the formation of AMHB. Altogether, our investigation provide novel, valuable insights about the complex mutual influence between hydrogen bonds and π systems.
Collapse
|
2
|
Gallo-Bueno A, Kohout M, Francisco E, Martín Pendás Á. Localization and Delocalization in Solids from Electron Distribution Functions. J Chem Theory Comput 2022; 18:4245-4254. [PMID: 35678769 DOI: 10.1021/acs.jctc.2c00234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The extent of electron localization and delocalization in molecular and condensed phases has been the subject of intense scrutiny over the years. In Chemistry, where real, instead of momentum space viewpoints are many times closer to intuition, a plethora of localization descriptors exist, including a family of indices invariant under orbital transformations that rely only on an underlying partition of the physical space into meaningful regions. These localization and delocalization indices measure the fluctuation of the electron population contained in such domains, and have been rigorously related to the insulating or conductive character of extended systems. Knowledge of the full electron population probability distribution function is also available in molecules, where it has provided many meaningful results as well as uncovered exotic interaction regimes in excited states. Electron distribution functions (EDFs), which can be seen as real space analogs of Pauling resonance structures, are now reported in periodic systems. In agreement with what is known in finite systems, ionic compounds display narrow EDFs that get wider as covalency sets in. Contrarily to conventional wisdom, most electrons delocalize over their nearest neighbors, even in quasi electron-gas metals like sodium, and it is only in the decay rate of the probability distribution where conductors and insulators can be distinguished.
Collapse
Affiliation(s)
- A Gallo-Bueno
- Center for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), Álava Technology Park, Albert Einstein 48, 01510 Vitoria-Gasteiz, Spain
| | - M Kohout
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
| | - E Francisco
- Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Á Martín Pendás
- Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33006 Oviedo, Spain
| |
Collapse
|
3
|
Guevara-Vela JM, Gallegos M, Valentín-Rodríguez MA, Costales A, Rocha-Rinza T, Pendás ÁM. On the Relationship between Hydrogen Bond Strength and the Formation Energy in Resonance-Assisted Hydrogen Bonds. Molecules 2021; 26:4196. [PMID: 34299473 PMCID: PMC8303970 DOI: 10.3390/molecules26144196] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 11/16/2022] Open
Abstract
Resonance-assisted hydrogen bonds (RAHB) are intramolecular contacts that are characterised by being particularly energetic. This fact is often attributed to the delocalisation of π electrons in the system. In the present article, we assess this thesis via the examination of the effect of electron-withdrawing and electron-donating groups, namely -F, -Cl, -Br, -CF3, -N(CH3)2, -OCH3, -NHCOCH3 on the strength of the RAHB in malondialdehyde by using the Quantum Theory of Atoms in Molecules (QTAIM) and the Interacting Quantum Atoms (IQA) analyses. We show that the influence of the investigated substituents on the strength of the investigated RAHBs depends largely on its position within the π skeleton. We also examine the relationship between the formation energy of the RAHB and the hydrogen bond interaction energy as defined by the IQA method of wave function analysis. We demonstrate that these substituents can have different effects on the formation and interaction energies, casting doubts regarding the use of different parameters as indicators of the RAHB formation energies. Finally, we also demonstrate how the energy density can offer an estimation of the IQA interaction energy, and therefore of the HB strength, at a reduced computational cost for these important interactions. We expected that the results reported herein will provide a valuable understanding in the assessment of the energetics of RAHB and other intramolecular interactions.
Collapse
Affiliation(s)
- José Manuel Guevara-Vela
- Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán, Mexico City C.P. 04510, Mexico; (J.M.G.-V.); (T.R.-R.)
| | - Miguel Gallegos
- Department of Analytical and Physical Chemistry, University of Oviedo, 33006 Oviedo, Spain; (M.G.); (A.C.)
| | - Mónica A. Valentín-Rodríguez
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas (IFF-CSIC), Serrano 123, 28006 Madrid, Spain;
| | - Aurora Costales
- Department of Analytical and Physical Chemistry, University of Oviedo, 33006 Oviedo, Spain; (M.G.); (A.C.)
| | - Tomás Rocha-Rinza
- Institute of Chemistry, National Autonomous University of Mexico, Circuito Exterior, Ciudad Universitaria, Delegación Coyoacán, Mexico City C.P. 04510, Mexico; (J.M.G.-V.); (T.R.-R.)
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo, 33006 Oviedo, Spain; (M.G.); (A.C.)
| |
Collapse
|
4
|
Understanding Topological Insulators in Real Space. Molecules 2021; 26:molecules26102965. [PMID: 34067586 PMCID: PMC8156361 DOI: 10.3390/molecules26102965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/14/2021] [Accepted: 05/04/2021] [Indexed: 11/16/2022] Open
Abstract
A real space understanding of the Su–Schrieffer–Heeger model of polyacetylene is introduced thanks to delocalization indices defined within the quantum theory of atoms in molecules. This approach enables to go beyond the analysis of electron localization usually enabled by topological insulator indices—such as IPR—enabling to differentiate between trivial and topological insulator phases. The approach is based on analyzing the electron delocalization between second neighbors, thus highlighting the relevance of the sublattices induced by chiral symmetry. Moreover, the second neighbor delocalization index, δi,i+2, also enables to identify the presence of chirality and when it is broken by doping or by eliminating atom pairs (as in the case of odd number of atoms chains). Hints to identify bulk behavior thanks to δ1,3 are also provided. Overall, we present a very simple, orbital invariant visualization tool that should help the analysis of chirality (independently of the crystallinity of the system) as well as spreading the concepts of topological behavior thanks to its relationship with well-known chemical concepts.
Collapse
|
5
|
Gil-Guerrero S, Peña-Gallego Á, Ramos-Berdullas N, Martín Pendás Á, Mandado M. Assessing the Reversed Exponential Decay of the Electrical Conductance in Molecular Wires: The Undeniable Effect of Static Electron Correlation. NANO LETTERS 2019; 19:7394-7399. [PMID: 31525054 DOI: 10.1021/acs.nanolett.9b03063] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An extraordinary new family of molecular junctions, inaccurately referred to as "anti-Ohmic" wires in the recent literature, has been proposed based on theoretical predictions. The unusual electron transport observed for these systems, characterized by a reversed exponential decay of their electrical conductance, might revolutionize the design of molecular electronic devices. This behavior, which has been associated with intrinsic diradical nature, is reexamined in this work. Since the diradical character arises from a near-degeneracy of the frontier orbitals, the employment of a multireference approach is mandatory. CASSCF calculations on a set of nanowires based on polycyclic aromatic hydrocarbons (PAHs) demonstrate that, in the frame of an appropriate multireference treatment, the ground state of these systems shows the expected exponential decay of the conductance. Interestingly, these calculations do evidence a reversed exponential decay of the conductance, although now in several excited states. Similar results have been obtained for other recently proposed candidates to "anti-Ohmic" wires. These findings open new horizons for possible applications in molecular electronics of these promising systems.
Collapse
Affiliation(s)
- Sara Gil-Guerrero
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| | - Ángeles Peña-Gallego
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| | - Nicolás Ramos-Berdullas
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
- Institute of Theoretical Chemistry , University of Vienna , Währinger Str. 17 , 1090 Vienna , Austria
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry , University of Oviedo , Calle Julián Clavería 8 , 33006 Oviedo , Spain
| | - Marcos Mandado
- Department of Physical Chemistry , University of Vigo , Lagoas-Marcosende s/n , 36310 Vigo , Spain
| |
Collapse
|
6
|
Pendás ÁM, Francisco E. Chemical Bonding from the Statistics of the Electron Distribution. Chemphyschem 2019; 20:2722-2741. [DOI: 10.1002/cphc.201900641] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Ángel Martín Pendás
- Departamento de Química Física y Analítica, Facultad de QuímicaUniversidad de Oviedo 33006- Oviedo Spain
| | - Evelio Francisco
- Departamento de Química Física y Analítica, Facultad de QuímicaUniversidad de Oviedo 33006- Oviedo Spain
| |
Collapse
|
7
|
Gil-Guerrero S, Ramos-Berdullas N, Martín Pendás Á, Francisco E, Mandado M. Anti-ohmic single molecule electron transport: is it feasible? NANOSCALE ADVANCES 2019; 1:1901-1913. [PMID: 36134239 PMCID: PMC9417330 DOI: 10.1039/c8na00384j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/07/2019] [Indexed: 06/10/2023]
Abstract
Hitherto, only molecular wires with a regular ohmic behavior in which the electric conductance decreases with the wire length have been synthesized. Implementation of molecular conductors with reversed conductance/length trend (anti-ohmic) might revolutionize the field of molecular electronics, allowing the development of electronic devices with extraordinary properties. It is for this reason that, recently, theoretical efforts have been focused on this topic and different structures have been proposed to show reversed conductance/length behavior on the basis of density functional theory non-equilibrium Green function approach (DFT-NEGF) and topological models. From the previous works, it can be stated that an anti-ohmic molecular wire must display a very small HOMO-LUMO gap and a reversed bond alternation pattern in the case of polyenes and related conjugated systems. In this work, the pursuit of a mechanism by which the anti-ohmic electron transport may arise was carried out by studying the paradigmatic anti-ohmic p-xylylene chain (pX2) at the DFT level in combination with topological models. It has been found that the electron transport in the anti-ohmic regime is favored by a long-range superexchange mechanism, which, contrary to what is expected, is reinforced by the increase in the length of the chain. Moreover, strong links between anti-ohmic character in molecular wires and one-dimensional topological insulator models have been established. Due to the small HOMO-LUMO gap predicted at DFT level, the anti-ohmic character has been put to the proof using a multireference scenario. Preliminary results point out to the presence of different ohmic and anti-ohmic electronic states. In the particular case of pX2 the anti-ohmic states do not correspond to the ground state. These findings require a reconsideration of previous studies on the reversed conductance/length behavior using single reference methodologies.
Collapse
Affiliation(s)
- Sara Gil-Guerrero
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
| | - Nicolás Ramos-Berdullas
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
- Institute of Theoretical Chemistry, University of Vienna Währinger Str. 17 1090 Vienna Austria
| | - Ángel Martín Pendás
- Department of Analytical and Physical Chemistry, University of Oviedo Calle Julían Clavería 8 33006 Oviedo Spain
| | - Evelio Francisco
- Department of Analytical and Physical Chemistry, University of Oviedo Calle Julían Clavería 8 33006 Oviedo Spain
| | - Marcos Mandado
- Department of Physical Chemistry, University of Vigo Lagoas-Marcosende s/n 36310 Vigo Spain
| |
Collapse
|
8
|
Aray Y, Barrios AD. Exploring the electron density localization in MoS 2 nanoparticles using a localized-electron detector: Unraveling the origin of the one-dimensional metallic sites on MoS 2 catalysts. Phys Chem Chem Phys 2018; 20:20417-20426. [PMID: 30042989 DOI: 10.1039/c8cp03387k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The nature of the electron density localization in two MoS2 nanoclusters containing eight rows of Mo atoms, one with 100% sulphur coverage at the Mo edges (n8_100S) and the other with 50% coverage (n8_50S) was studied using a localized-electron detector function defined in the local moment representation. For n8_100S, pairs of neighboring S2 dimers cover the edges and the electron density localization function analysis shows the presence of a local triangular-shaped ring zone of highly delocalized electrons along these edges, which corresponds to a good metallic conductor zone. The optimized geometry analysis shows that the Mo-S2 bond length is much longer than that of the Mo-S bonds inside the cluster. The removal of one S atom from each sulphur dimer to create a cluster with 50% coverage produces a general compressive stress on the cluster optimized geometry, which shortens the Mo-S bond length, particularly at the edge. The electron density location function analysis shows that close to the cluster corners, a zone of highly delocalized electron zones with a characteristic semiconductor pattern and broken one-dimensional metallic ring was generated. These results suggest that the Mo-S2 bond elongation produced by the sulphur dimers is similar to a MoS2 monolayer under tensile strain and is the origin of the one-dimensional metallic sites at the Mo-edges. In general, the present findings show excellent agreement with the key features of the reported ambient pressure X-ray photoemission spectra and the corresponding simulated scanning tunneling microscopy images.
Collapse
Affiliation(s)
- Yosslen Aray
- Universidad de Ciencias Aplicadas y Ambientales, UDCA, Facultad de Ciencias, Campus Universitario Norte, Calle 222 No 55-37, Bogotá, Colombia.
| | | |
Collapse
|
9
|
Martín Pendás A, Francisco E. Real space bond orders are energetic descriptors. Phys Chem Chem Phys 2018; 20:16231-16237. [DOI: 10.1039/c8cp02485e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Orbital invariant position space techniques are used to show a theoretical link between the conventional concept of bond order and the energetics of chemical interactions.
Collapse
Affiliation(s)
- A. Martín Pendás
- Departamento de Química Física y Analítica
- Universidad de Oviedo
- Oviedo
- Spain
| | - E. Francisco
- Departamento de Química Física y Analítica
- Universidad de Oviedo
- Oviedo
- Spain
| |
Collapse
|
10
|
Aray Y, Paredes R, Álvarez LJ, Martiz A. On the electron density localization in elemental cubic ceramic and FCC transition metals by means of a localized electrons detector. J Chem Phys 2017; 146:224504. [PMID: 29166084 DOI: 10.1063/1.4985253] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The electron density localization in insulator and semiconductor elemental cubic materials with diamond structure, carbon, silicon, germanium, and tin, and good metallic conductors with face centered cubic structure such as α-Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au, was studied using a localized electrons detector defined in the local moment representation. Our results clearly show an opposite pattern of the electron density localization for the cubic ceramic and transition metal materials. It was found that, for the elemental ceramic materials, the zone of low electron localization is very small and is mainly localized on the atomic basin edges. On the contrary, for the transition metals, there are low-valued localized electrons detector isocontours defining a zone of highly delocalized electrons that extends throughout the material. We have found that the best conductors are those in which the electron density at this low-value zone is the lowest.
Collapse
Affiliation(s)
- Yosslen Aray
- Centro de Química, Facultad de Ciencias, Universidad de Ciencias Aplicadas y Ambientales, UDCA, Campus Universitario Norte, Calle 222 No. 55-37, Bogotá, Colombia
| | - Ricardo Paredes
- Facultad de Ingeniería en Ciencias de la Tierra, Escuela Superior Politécnica del Litoral, Km 30.5 Via Perimetral, Guayaquil, Ecuador
| | - Luis Javier Álvarez
- Laboratorio de Simulación, Unidad Cuernavaca, Instituto de Matemáticas, Universidad Nacional Autónoma de México, AP-273-3, Cuernavaca, Morelos 62251, Mexico
| | - Alejandro Martiz
- Department of Inorganic Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1521 Budapest, Hungary
| |
Collapse
|
11
|
Manz TA. Introducing DDEC6 atomic population analysis: part 3. Comprehensive method to compute bond orders. RSC Adv 2017. [DOI: 10.1039/c7ra07400j] [Citation(s) in RCA: 230] [Impact Index Per Article: 32.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A new method to compute accurate bond orders for metallic, covalent, polar-covalent, ionic, multi-centered, aromatic, dative, dispersion, and hydrogen bonding.
Collapse
Affiliation(s)
- Thomas A. Manz
- Department of Chemical & Materials Engineering
- New Mexico State University
- Las Cruces
- USA
| |
Collapse
|