Highly Strained Phenylene Bicyclophanes

Ohlendorf, Gabi; Mahler, Christian; Jester, Stefan‐S.; Schnakenburg, Gregor; Höger, Sigurd

doi:10.1002/ange.201306299

Cited by 18 publications

(4 citation statements)

References 32 publications

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“…The orientation of long chain alkanes and their derivatives (acids, alcohols, amines, etc.) including the precise arrangement of their atoms on the basal plane of graphite has been studied and evaluated both theoretically and experimentally in numerous works (e.g., see refs − ). Despite the fact that the first model of alkane chain orientation on graphite appeared long before the invention of scanning probe microscopy (SPM), nowadays, SPM, primarily scanning tunneling microscopy (STM) and atomic force microscopy (AFM), is the main experimental approach for the investigation of self-assembled monolayers because high-resolution images of molecular nanotemplates can be acquired.…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

2014

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In this work, we have studied the conformation of DNA molecules aligned on the nanotemplates of octadecylamine, stearyl alcohol, and stearic acid on highly oriented pyrolytic graphite (HOPG). For this purpose, fluctuations of contours of adsorbed biopolymers obtained from atomic force microscopy (AFM) images were analyzed using the wormlike chain model. Moreover, the conformations of adsorbed biopolymer molecules were characterized by the analysis of the scaling exponent ν, which relates the mean squared end-to-end distance and contour length of the polymer. During adsorption on octadecylamine and stearyl alcohol nanotemplates, DNA forms straight segments, which order along crystallographic axes of graphite. In this case, the conformation of DNA molecules can be described using two different length scales. On a large length scale (at contour lengths l > 200-400 nm), aligned DNA molecules have either 2D compact globule or partially relaxed 2D conformation, whereas on a short length scale (at l ≤ 200-400 nm) their conformation is close to that of rigid rods. The latter type of conformation can be also assigned to DNA adsorbed on a stearic acid nanotemplate. The different conformation of DNA molecules observed on the studied monolayers is connected with the different DNA-nanotemplate interactions associated with the nature of the functional group of the alkane derivative in the nanotemplate (amine, alcohol, or acid). The persistence length of λ-DNA adsorbed on octadecylamine nanotemplates is 31 ± 2 nm indicating the loss of DNA rigidity in comparison with its native state. Similar values of the persistence length (34 ± 2 nm) obtained for 24-times shorter DNA molecules adsorbed on an octadecylamine nanotemplate demonstrate that this rigidity change does not depend on biopolymer length. Possible reasons for the reduction of DNA persistence length are discussed in view of the internal DNA structure and DNA-surface interaction.

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Section: Introductionmentioning

confidence: 99%

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

2014

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“…Though these conformational energies might seem daunting, synthetic chemists have created and stabilized molecules with strain energies over 300 kJ mol −1 . 79,80 For certain TADF emitters, the maximum TADF conformation might be synthesizable using suitable modifications in the real universe.…”

Section: Other Model Systemsmentioning

confidence: 99%

Maximizing TADF via Conformational Optimization

Kim

Voorhis

2021

J. Phys. Chem. A

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We investigate a new strategy to enhance thermally activated delayed fluorescence (TADF) in organic light-emitting diodes (OLEDs). Given that the TADF rate of a molecule depends on its conformation, we hypothesize that there exists a conformation that maximizes the TADF rate. In order to test this idea, we use time-dependent density functional theory (TDDFT) to simulate the TADF rates of several TADF emitters, while shifting their geometries towards higher TADF rates in a select subspace of internal coordinates. We find that geometric changes in this subspace can increase the TADF rate up to three orders of magnitude with respect to the minimum energy conformation, and the simulated TADF rate can even be brought into the submicrosecond timescales under the right conditions. Furthermore, the TADF rate enhancement can be maintained with a conformational energy that might be within the reach of modern synthetic chemistry. Analyzing the maximum TADF conformation, we extract a number of structural motifs that might provide a useful handle on the TADF rate of a donor-acceptor (DA) system. The incorporation of conformational engineering into the TADF technology could usher in a new paradigm of OLEDs.

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“…Though these conformational energies might seem daunting, synthetic chemists have created and stabilized molecules with strain energies over 300 kJ mol −1 . 78,79 For certain TADF emitters, the maximum TADF conformation might be accessible using suitable techniques in the real universe.…”

Section: Dcztrzmentioning

confidence: 99%

Maximizing TADF via Conformational Optimization

Kim

Voorhis²

2021

Preprint

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We investigate a new strategy to enhance thermally activated delayed fluorescence (TADF) in organic light-emitting diodes (OLEDs). Given that the TADF rate of a molecule depends on its conformation, we hypothesize that there exists a conformation that maximizes the TADF rate. In order to test this idea, we use time-dependent density functional theory (TD-DFT) to simulate the TADF rates of several TADF emitters, while shifting their geometries towards higher TADF rates in a select subspace of internal coordinates. We find that geometric changes in this subspace can increase the TADF rate up to three orders of magnitude with respect to the minimum energy conformation, and the simulated TADF rate can even be brought into the submicrosecond timescales under the right conditions. Furthermore, the rate enhancement can be maintained with a conformational energy that are within the reach of modern synthetic chemistry. Analyzing the maximum TADF conformation, we extract a number of structural motifs that might provide a useful handle on the TADF rate of a donor-acceptor (DA) system. The incorporation of conformational engineering into the TADF technology could usher in a new paradigm of OLEDs.

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Highly Strained Phenylene Bicyclophanes

Cited by 18 publications

References 32 publications

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

Statistical Analysis of Molecular Nanotemplate Driven DNA Adsorption on Graphite

Maximizing TADF via Conformational Optimization

Maximizing TADF via Conformational Optimization

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