Role of H-optimization in the computed intermolecular interactions and charge-transfer integrals in diketopyrrolopyrroles

Jesus Calvo-Castro, Alan R. Kennedy, Callum J. McHugh

Research output: Contribution to journalArticle

Abstract

Small organic conjugated systems displaying one-dimensional stacking motifs in the solid state that facilitate charge propagation are highly desirable. Noncovalent interactions, although weak, can synergistically provide those supramolecular architectures with large binding energies and associated thermal integrity. Amongst the plethora of intermolecular interactions contributing toward the overall lattice energy and stability of the charge-propagation supramolecular architectures, H-bonding interactions are well-known to play a pivotal role. Despite their critical contribution, the positions of hydrogen atoms in X-ray crystallographic data are parameterized, which can lead to significant changes in the computed intermolecular interactions. Herein, we report for the first time an analysis of the role that the optimization of the H atoms in X-ray structures has in the computed intermolecular interactions energies in diketopyrrolopyrroles (DPPs). A large dataset comprising 94 dimer pairs from 19 different DPP-based systems, including three pigment analogues, was employed. In total, more than 1400 H–X chemical bonds were considered and optimized using the M06-2X density functional at the 6-311G(d) level. Intermolecular interactions were computed for the H-optimized geometries and compared to those from nonoptimized counterparts. We report that in 35 out of the 94 dimer pairs investigated (37%), the computed intermolecular interactions were at least 2.5 kJ mol–1 larger on progression to the H-optimized geometries. In turn, lower computed values were yielded upon H-optimization computed for 8 out of the 94 dimer pairs (8%), with one case exhibiting a difference greater than 2.5 kJ mol–1. In line with the negligible changes to electron density and wavefunction overlap, the computed changes on the transfer integrals for the hole and electron were always lower than 1 kJ mol–1. The observed changes to computed intermolecular interactions can play a critical role in determining the thermal integrity of the supramolecular structures and charge propagation channels, and thus in the absence of neutron diffraction data, H atoms should be optimized prior to computation. We envisage that the results herein will be of interest to the extensive scientific community devoted to the understanding of intermolecular interactions in organic conjugated systems and the realization of superior charge-transfer-mediating materials, and given the plethora of intermolecular interactions investigated, the results are not solely limited to DPP-based architectures.
Original languageEnglish
Pages (from-to)3185−3193
Number of pages9
JournalJournal of Physical Chemistry A
Volume123
Issue number14
Early online date21 Mar 2019
DOIs
Publication statusPublished - 11 Apr 2019

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Dimers
Charge transfer
Atoms
X rays
Geometry
Chemical bonds
Neutron diffraction
Wave functions
Binding energy
Pigments
Carrier concentration
Hydrogen
Electrons
Hot Temperature

Cite this

@article{d79d8f909f9c48b9a42f6039149e2011,
title = "Role of H-optimization in the computed intermolecular interactions and charge-transfer integrals in diketopyrrolopyrroles",
abstract = "Small organic conjugated systems displaying one-dimensional stacking motifs in the solid state that facilitate charge propagation are highly desirable. Noncovalent interactions, although weak, can synergistically provide those supramolecular architectures with large binding energies and associated thermal integrity. Amongst the plethora of intermolecular interactions contributing toward the overall lattice energy and stability of the charge-propagation supramolecular architectures, H-bonding interactions are well-known to play a pivotal role. Despite their critical contribution, the positions of hydrogen atoms in X-ray crystallographic data are parameterized, which can lead to significant changes in the computed intermolecular interactions. Herein, we report for the first time an analysis of the role that the optimization of the H atoms in X-ray structures has in the computed intermolecular interactions energies in diketopyrrolopyrroles (DPPs). A large dataset comprising 94 dimer pairs from 19 different DPP-based systems, including three pigment analogues, was employed. In total, more than 1400 H–X chemical bonds were considered and optimized using the M06-2X density functional at the 6-311G(d) level. Intermolecular interactions were computed for the H-optimized geometries and compared to those from nonoptimized counterparts. We report that in 35 out of the 94 dimer pairs investigated (37{\%}), the computed intermolecular interactions were at least 2.5 kJ mol–1 larger on progression to the H-optimized geometries. In turn, lower computed values were yielded upon H-optimization computed for 8 out of the 94 dimer pairs (8{\%}), with one case exhibiting a difference greater than 2.5 kJ mol–1. In line with the negligible changes to electron density and wavefunction overlap, the computed changes on the transfer integrals for the hole and electron were always lower than 1 kJ mol–1. The observed changes to computed intermolecular interactions can play a critical role in determining the thermal integrity of the supramolecular structures and charge propagation channels, and thus in the absence of neutron diffraction data, H atoms should be optimized prior to computation. We envisage that the results herein will be of interest to the extensive scientific community devoted to the understanding of intermolecular interactions in organic conjugated systems and the realization of superior charge-transfer-mediating materials, and given the plethora of intermolecular interactions investigated, the results are not solely limited to DPP-based architectures.",
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Role of H-optimization in the computed intermolecular interactions and charge-transfer integrals in diketopyrrolopyrroles. / Calvo-Castro, Jesus; Kennedy, Alan R. ; McHugh, Callum J.

In: Journal of Physical Chemistry A, Vol. 123, No. 14, 11.04.2019, p. 3185−3193.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Role of H-optimization in the computed intermolecular interactions and charge-transfer integrals in diketopyrrolopyrroles

AU - Calvo-Castro, Jesus

AU - Kennedy, Alan R.

AU - McHugh, Callum J.

PY - 2019/4/11

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N2 - Small organic conjugated systems displaying one-dimensional stacking motifs in the solid state that facilitate charge propagation are highly desirable. Noncovalent interactions, although weak, can synergistically provide those supramolecular architectures with large binding energies and associated thermal integrity. Amongst the plethora of intermolecular interactions contributing toward the overall lattice energy and stability of the charge-propagation supramolecular architectures, H-bonding interactions are well-known to play a pivotal role. Despite their critical contribution, the positions of hydrogen atoms in X-ray crystallographic data are parameterized, which can lead to significant changes in the computed intermolecular interactions. Herein, we report for the first time an analysis of the role that the optimization of the H atoms in X-ray structures has in the computed intermolecular interactions energies in diketopyrrolopyrroles (DPPs). A large dataset comprising 94 dimer pairs from 19 different DPP-based systems, including three pigment analogues, was employed. In total, more than 1400 H–X chemical bonds were considered and optimized using the M06-2X density functional at the 6-311G(d) level. Intermolecular interactions were computed for the H-optimized geometries and compared to those from nonoptimized counterparts. We report that in 35 out of the 94 dimer pairs investigated (37%), the computed intermolecular interactions were at least 2.5 kJ mol–1 larger on progression to the H-optimized geometries. In turn, lower computed values were yielded upon H-optimization computed for 8 out of the 94 dimer pairs (8%), with one case exhibiting a difference greater than 2.5 kJ mol–1. In line with the negligible changes to electron density and wavefunction overlap, the computed changes on the transfer integrals for the hole and electron were always lower than 1 kJ mol–1. The observed changes to computed intermolecular interactions can play a critical role in determining the thermal integrity of the supramolecular structures and charge propagation channels, and thus in the absence of neutron diffraction data, H atoms should be optimized prior to computation. We envisage that the results herein will be of interest to the extensive scientific community devoted to the understanding of intermolecular interactions in organic conjugated systems and the realization of superior charge-transfer-mediating materials, and given the plethora of intermolecular interactions investigated, the results are not solely limited to DPP-based architectures.

AB - Small organic conjugated systems displaying one-dimensional stacking motifs in the solid state that facilitate charge propagation are highly desirable. Noncovalent interactions, although weak, can synergistically provide those supramolecular architectures with large binding energies and associated thermal integrity. Amongst the plethora of intermolecular interactions contributing toward the overall lattice energy and stability of the charge-propagation supramolecular architectures, H-bonding interactions are well-known to play a pivotal role. Despite their critical contribution, the positions of hydrogen atoms in X-ray crystallographic data are parameterized, which can lead to significant changes in the computed intermolecular interactions. Herein, we report for the first time an analysis of the role that the optimization of the H atoms in X-ray structures has in the computed intermolecular interactions energies in diketopyrrolopyrroles (DPPs). A large dataset comprising 94 dimer pairs from 19 different DPP-based systems, including three pigment analogues, was employed. In total, more than 1400 H–X chemical bonds were considered and optimized using the M06-2X density functional at the 6-311G(d) level. Intermolecular interactions were computed for the H-optimized geometries and compared to those from nonoptimized counterparts. We report that in 35 out of the 94 dimer pairs investigated (37%), the computed intermolecular interactions were at least 2.5 kJ mol–1 larger on progression to the H-optimized geometries. In turn, lower computed values were yielded upon H-optimization computed for 8 out of the 94 dimer pairs (8%), with one case exhibiting a difference greater than 2.5 kJ mol–1. In line with the negligible changes to electron density and wavefunction overlap, the computed changes on the transfer integrals for the hole and electron were always lower than 1 kJ mol–1. The observed changes to computed intermolecular interactions can play a critical role in determining the thermal integrity of the supramolecular structures and charge propagation channels, and thus in the absence of neutron diffraction data, H atoms should be optimized prior to computation. We envisage that the results herein will be of interest to the extensive scientific community devoted to the understanding of intermolecular interactions in organic conjugated systems and the realization of superior charge-transfer-mediating materials, and given the plethora of intermolecular interactions investigated, the results are not solely limited to DPP-based architectures.

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M3 - Article

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SP - 3185−3193

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

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