Structural Dynamics of Overcrowded Alkene-Based Molecular Motors during Thermal Isomerization

Cnossen, Arjen; Kistemaker, Jos C. M.; Kojima, Tatsuo; Feringa, Bernard

doi:10.1021/jo402301j

Cited by 56 publications

(96 citation statements)

References 39 publications

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“…As a very valuable complement to these experimental efforts, a number of computational studies have been performed to investigate the mechanisms of both the photoisomerizations [50–55] and the thermal isomerizations [29, 50, 56–58] of overcrowded alkene-based motors, or to suggest alternative motor designs [59–65], including systems whose photochemical steps may be particularly efficient [65] or whose rotary cycles may consist of photochemical steps only [63, 64]. Although the thermal isomerization mechanisms of both first and second-generation motors have been explored using semiempirical [50, 56], DFT [29, 58], and Monte Carlo-like methods [57], until recently, there had been no systematic quantum chemical study of ways to lower the thermal free-energy barriers of overcrowded alkene-based motors.…”

Section: Introductionmentioning

confidence: 99%

“…Although the thermal isomerization mechanisms of both first and second-generation motors have been explored using semiempirical [50, 56], DFT [29, 58], and Monte Carlo-like methods [57], until recently, there had been no systematic quantum chemical study of ways to lower the thermal free-energy barriers of overcrowded alkene-based motors. Therefore, we decided to take a first step toward filling this gap by investigating the possibility to accelerate the thermal isomerizations of motor 1a through modulation of steric interactions [42, 66].…”

Section: Introductionmentioning

confidence: 99%

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On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

Oruganti

Durbeej

2016

J Mol Model

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We employ computational methods to investigate the possibility of using electron-donating or electron-withdrawing substituents to reduce the free-energy barriers of the thermal isomerizations that limit the rotational frequencies achievable by synthetic overcrowded alkene-based molecular motors. Choosing as reference systems one of the fastest motors known to date and two variants thereof, we consider six new motors obtained by introducing electron-donating methoxy and dimethylamino or electron-withdrawing nitro and cyano substituents in conjugation with the central olefinic bond connecting the two (stator and rotator) motor halves. Performing density functional theory calculations, we then show that electron-donating (but not electron-withdrawing) groups at the stator are able to reduce the already small barriers of the reference motors by up to 18 kJ mol−1. This result outlines a possible strategy for improving the rotational frequencies of motors of this kind. Furthermore, exploring the origin of the catalytic effect, it is found that electron-donating groups exert a favorable steric influence on the thermal isomerizations, which is not manifested by electron-withdrawing groups. This finding suggests a new mechanism for controlling the critical steric interactions of these motors.Graphical AbstractThe introduction of electron-donating groups in one of the fastest rotary molecular motors known to date is found to reduce the free-energy barriers of the thermal steps that limit the rotational frequencies by up to 18 kJ mol−1.Electronic supplementary materialThe online version of this article (doi:10.1007/s00894-016-3085-y) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

Oruganti

Durbeej

2016

J Mol Model

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“…The other approach uses reversible photoswitches that can exist in two stable states. Azobenzenes,21–23 spiropyrans,24–28 diarylethenes,29–33 fulgide,34–36 fulgimide,37, 38 hemithioindigos,39–41 and overcrowded alkenes42, 43 are prominent switches, and most of these switches have already been applied to the regulation of nucleic acids. For the light control of nucleic acids, the photoswitch itself and the linker that connects the photoswitch to the oligonucleotide are very important for an effective regulation event.…”

Section: Introductionmentioning

confidence: 99%

Azobenzene C‐Nucleosides for Photocontrolled Hybridization of DNA at Room Temperature

Goldau

Murayama

Brieke

et al. 2015

Chemistry A European J

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Herein, we report the reversible light-regulated destabilization of DNA duplexes by using azobenzene C-nucleoside photoswitches. The incorporation of two different azobenzene residues into DNA and their photoswitching properties are described. These new residues demonstrate a photoinduced destabilization effect comparable to the widely applied D-threoninol-linked azobenzene switch, which is currently the benchmark. The photoswitches presented herein show excellent photoswitching efficiencies in DNA duplexes - even at room temperature - which are superior to commonly used azobenzene-based nucleic acid photoswitches. In addition, these photoswitching residues exhibit high thermal stability and excellent fatigue resistance, thus rendering them one of the most efficient candidates for the regulation of duplex stability with light.

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“…Feringa et al designed UV/Vis and NIR light-responsive spiropyran self-assembled monolayers on polycrystalline gold surfaces. Interestingly, a series of first-generation light-driven molecular motors based on overcrowded alkenes and chiral Nalkyl imines [34] has been synthesized [35][36][37][38][39][40]. Interestingly, a series of first-generation light-driven molecular motors based on overcrowded alkenes and chiral Nalkyl imines [34] has been synthesized [35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Isatin N²-diphenylhydrazones: new easily synthesized Vis-Vis molecular photoswitches

et al. 2015

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The photochromic properties of isatin N 2 -diphenylhydrazones as a new type of molecular switches were investigated. Interestingly, dimerization stabilizes the formation of only E-isomers in synthesis, even without Z-isomer presence in the mother liquor. The irradiation of E-isomers in solution at their absorption maxima leads to the formation of the corresponding Z-isomers. Although the shift in absorption maximum is not large and photochemical quantum yields are lower compared than in commonly used photoswitches, the absorbance changes are sufficient for potential practical use of these compounds as On-Off switches when the readout wavelength is optimally selected. The process is reversible and switching cycles can be repeated many times in both directions. Determined thermodynamic parameters and calculated geometry of the transition state clearly indicate the inverse mechanism of thermally initiated slow back Z-E isomerization. Due to the Vis-Vis character of molecular photoswitching and significant geometric changes during the switching process, isatin N 2 -diphenylhydrazones are eminently suitable for molecular switching in biological/biotechnological applications. Moreover, the interaction of isatin N 2 -diphenylhydrazones with strongly basic anions increases their functionality and creates a four-state On-Off switch in one molecule. This four-state switch includes the unique E-Z isomerization induced photochemical switching between two stable tautomeric forms of organic amide anion. Simple synthesis of these derivatives and their sufficiently sensitive response to external stimuli promote isatin N 2 -diphenylhydrazones as suitable candidates for both discussed photochemistry areas (molecular switching and actinometry).

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Structural Dynamics of Overcrowded Alkene-Based Molecular Motors during Thermal Isomerization

Cited by 56 publications

References 39 publications

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

Azobenzene C‐Nucleosides for Photocontrolled Hybridization of DNA at Room Temperature

Isatin N²-diphenylhydrazones: new easily synthesized Vis-Vis molecular photoswitches

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Structural Dynamics of Overcrowded Alkene-Based Molecular Motors during Thermal Isomerization

Cited by 56 publications

References 39 publications

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

On the possibility to accelerate the thermal isomerizations of overcrowded alkene-based rotary molecular motors with electron-donating or electron-withdrawing substituents

Azobenzene C‐Nucleosides for Photocontrolled Hybridization of DNA at Room Temperature

Isatin N2-diphenylhydrazones: new easily synthesized Vis-Vis molecular photoswitches

Contact Info

Product

Resources

About

Isatin N²-diphenylhydrazones: new easily synthesized Vis-Vis molecular photoswitches