Relation between bond order and delocalization index of QTAIM

Ab initio quantum chemistry is an independent source of information supplying an ever widening group of experimental chemists. However, bridging the gap between these ab initio data and chemical insight remains a challenge. In particular, there is a need for a bond order index that characterizes novel bonding patterns in a reliable manner, while recovering the familiar effects occurring in well-known bonds. In this article, through a large body of calculations, we show how the delocalization index derived from Quantum Chemical Topology (QCT) serves as such a bond order. This index is defined in a parameter-free, intuitive and consistent manner, and with little qualitative dependency on the level of theory used. The delocalization index is also able to detect the subtler bonding effects that underpin most practical organic and inorganic chemistry. We explore and connect the properties of this index and open the door for its extensive usage in the understanding and discovery of novel chemistry.

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Revitalizing the Concept of Bond Order Through Delocalization Measures in Real Space

10.26434/chemrxiv.6015848 ◽

2018 ◽

Author(s):

Carlos Outeiral Rubiera ◽

Mark Vincent ◽

Ángel Martín Pendás ◽

Paul L. A. Popelier

Keyword(s):

Ab Initio ◽

Quantum Chemical ◽

Bond Order ◽

Large Body ◽

Real Space ◽

Chemical Topology ◽

Delocalization Index ◽

Consistent Manner ◽

Quantum Chemical Topology ◽

Source Of Information

Ab initio quantum chemistry is an independent source of information supplying an ever widening group of experimental chemists. However, bridging the gap between these ab initio data and chemical insight remains a challenge. In particular, there is a need for a bond order index that characterizes novel bonding patterns in a reliable manner, while recovering the familiar effects occurring in well-known bonds. In this article, through a large body of calculations, we show how the delocalization index derived from Quantum Chemical Topology (QCT) serves as such a bond order. This index is defined in a parameter-free, intuitive and consistent manner, and with little qualitative dependency on the level of theory used. The delocalization index is also able to detect the subtler bonding effects that underpin most practical organic and inorganic chemistry. We explore and connect the properties of this index and open the door for its extensive usage in the understanding and discovery of novel chemistry.

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New Methods for Prediction of Bond Order of Mono and Diatomic Homo and Hetero Nuclear Molecules or Ions Having (1-20) E¯S and Oxide Based Acid Radicals Without Mot – A Rapid Innovative Approach

Indian Journal Of Applied Research ◽

10.15373/2249555x/nov2013/13 ◽

2011 ◽

Vol 3 (11) ◽

pp. 41-43

Author(s):

ARIJIT DAS ◽

Keyword(s):

Bond Order ◽

Innovative Approach ◽

New Methods ◽

Nuclear Molecules

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Bond order indices of iodine: from molecular complexes to crystals

Журнал структурной химии ◽

10.26902/jsc20180819 ◽

2018 ◽

Vol 59 (8) ◽

Keyword(s):

Bond Order ◽

Molecular Complexes

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Ion conformation and orientational order in a dicationic ionic liquid crystal studied by solid-state nuclear magnetic resonance spectroscopy

Scientific Reports ◽

10.1038/s41598-021-85021-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Debashis Majhi ◽

Sergey V. Dvinskikh

Keyword(s):

Ionic Liquid ◽

Ionic Liquids ◽

Liquid Crystals ◽

Bond Order ◽

Van Der Waals ◽

Orientational Order ◽

Smectic Phase ◽

Side Chains ◽

Dicationic Ionic Liquid ◽

Ionic Liquid Crystals

AbstractIonic liquids crystals belong to a special class of ionic liquids that exhibit thermotropic liquid-crystalline behavior. Recently, dicationic ionic liquid crystals have been reported with a cation containing two single-charged ions covalently linked by a spacer. In ionic liquid crystals, electrostatic and hydrogen bonding interactions in ionic sublayer and van der Waals interaction in hydrophobic domains are the main forces contributing to the mesophase stabilization and determining the molecular orientational order and conformation. How these properties in dicationic materials are compared to those in conventional monocationic analogs? We address this question using a combination of advanced NMR methods and DFT analysis. Dicationic salt 3,3′-(1,6-hexanediyl)bis(1-dodecylimidazolium)dibromide was studied. Local bond order parameters of flexible alkyl side chains, linker chain, and alignment of rigid polar groups were analyzed. The dynamic spacer effectively “decouples” the motion of two ionic moieties. Hence, local order and alignment in dicationic mesophase were similar to those in analogous single-chain monocationic salts. Bond order parameters in the side chains in the dicationic smectic phase were found consistently lower compared to double-chain monocationic analogs, suggesting decreasing contribution of van der Waals forces. Overall dication reorientation in the smectic phase was characterized by low values of orientational order parameter S. With increased interaction energy in the polar domain the layered structure is stabilized despite less ordered dications. The results emphasized the trends in the orientational order in ionic liquid crystals and contributed to a better understanding of interparticle interactions driving smectic assembly in this and analogous ionic mesogens.

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DFT Study of Electronic Structure and Optical Properties of Kaolinite, Muscovite, and Montmorillonite

Crystals ◽

10.3390/cryst11060618 ◽

2021 ◽

Vol 11 (6) ◽

pp. 618

Author(s):

Layla Shafei ◽

Puja Adhikari ◽

Wai-Yim Ching

Keyword(s):

Mechanical Properties ◽

Optical Properties ◽

Electronic Structure ◽

Hydrogen Bonds ◽

Clay Minerals ◽

Clay Mineral ◽

Bond Order ◽

Deep Understanding ◽

Pharmaceutical Applications ◽

Structure Properties

Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

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