Intuitive Understanding of σ Delocalization in Loose and σ Localization in Tight Helical Conformations of an Oligosilane Chain

Jovanović, Milena; Antic, Dean; Rooklin, David; Bande, Annika; Michl, Josef

doi:10.1002/asia.201700226

Cited by 19 publications

(35 citation statements)

References 49 publications

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“…Michl and coworkers disclosed the importance of geminal delocalization in oligosilanes . These fully saturated chains with an all‐silicon backbone have interesting optical properties that are highly sensitive to the backbone conformation.…”

Section: Types Of Hyperconjugationmentioning

confidence: 99%

Hyperconjugation

Alabugin

Gomes

Abdo

2018

WIREs Comput Mol Sci

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This review outlines the role of hyperconjugative interactions in the structure and reactivity of organic molecules. After defining the common hyperconjugative patterns, we discuss the main factors controlling the magnitude of hyperconjugative effects, including orbital symmetry, energy gap, electronegativity, and polarizability. The danger of underestimating the contribution of hyperconjugative interactions are illustrated by a number of spectroscopic, conformational, and structural effects. The stereoelectronic nature of hyperconjugation offers useful ways for control of molecular stability and reactivity. New manifestations of hyperconjugative effects continue to be uncovered by theory and experiments. This article is categorized under: Structure and Mechanism > Molecular Structures Software > Molecular Modeling Structure and Mechanism > Reaction Mechanisms and Catalysis

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Section: Types Of Hyperconjugationmentioning

confidence: 99%

Hyperconjugation

Alabugin

Gomes

Abdo

2018

WIREs Comput Mol Sci

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“…Permethylation also induces a helical twist in the chain but this does not appear to change the nature of the current density. 58,59 Conclusion To summarize, we have shown that while the chemical frameworks normally used to understand the structure-property relationships work well for conjugated molecules, they break down for saturated molecules. In alkanes, the current density showed a pipe-like character where the charge takes the shortest path possible and the nuclei define the diameter of the pipe.…”

Section: Increasing σ-Conjugationmentioning

confidence: 97%

When Current Does Not Follow Bonds: Current Density in Saturated Molecules

2019

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The tools commonly used to understand structure-property relationships in molecular conductance, inter-atomic currents and conductance eigenchannels, generally give us a sense of familiarity, with the chemical bonding framework and molecular orbitals reflected in the current. Here we show that while this picture is true for conjugated molecules, it breaks down in saturated systems. We investigate the current density in saturated chains of alkanes, silanes and germanes and show that the current density does not follow the bonds, but rather the nuclei define the diameter of a pipe through which the current flows. We discuss how this picture of current density can be used to understand details about the electron transport properties of these molecules. Understanding the spatial distribution of current through molecules, rather than simply the magnitude, provides a powerful tool for chemical insight into physical properties of molecules that are related to current flow.

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“…Altering the molecular structure allows a finetuning of the s-interference effect. Understanding this interplay between the different atoms in sconjugated molecules using simple electronic structure models [20][21] will be an important goal for future work. A special property of Si222 is that the insulating bicyclic unit is, in theory, more insulating than a gap the same dimensions.…”

Section: Scheme 2 Variation Of the Bicyclo[222]octane Motifmentioning

confidence: 99%

The Bicyclo[2.2.2]octane Motif: A Class of Saturated Group 14 Quantum Interference Based Single-molecule Insulators

Garner¹,

Koerstz²,

Jensen

et al. 2018

Preprint

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The electronic transmission through σ-conjugated molecules can be fully suppressed by destructive quantum interference, which makes them potential candidates for single-molecule insulators. The first molecule with clear suppression of the single-molecule conductance due to σ-interference was recently found in the form of a functionalized bicyclo[2.2.2]octasilane. Here we continue the search for potential single-molecule insulators based on saturated group 14 molecules. Using a high-throughput screening approach, we assess the electron transport properties of the bicyclo[2.2.2]octane class by systematically varying the constituent atoms between carbon, silicon, and germanium, thus exploring the full chemical space of 771 different molecules. The majority of the molecules in the bicyclo[2.2.2]octane class are found to be highly insulating molecules. Though the all-silicon molecule is a clear-cut case of σ-interference, it is not unique within its class and there are many potential molecules that we predict to be more insulating. The finding of this class of quantum interference based single-molecule insulators indicates that a broad range of highly insulating saturated group 14 molecules are likely to exist

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Intuitive Understanding of σ Delocalization in Loose and σ Localization in Tight Helical Conformations of an Oligosilane Chain

Cited by 19 publications

References 49 publications

Hyperconjugation

Hyperconjugation

When Current Does Not Follow Bonds: Current Density in Saturated Molecules

The Bicyclo[2.2.2]octane Motif: A Class of Saturated Group 14 Quantum Interference Based Single-molecule Insulators

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