The Hammett Relationship and Reactions in the Excited Electronic State:  Hemithioindigo<i>Z</i>/<i>E</i>-Photoisomerization

Cordes, Thorben; Schadendorf, Torsten; Priewisch, Beate; Rück‐Braun, K.; Zinth, Wolfgang

doi:10.1021/jp077472l

Cited by 76 publications

(73 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The derivatives which include a strong donor-acceptor X-Y pair followed another trend of reactivity. The Hammett relationship has also been found for hemithioindigo Z/E photoisomerization [12]. There are other reports concerning the experimentally investigated substituent dependence of the reaction kinetics in the first excited state; for example, proton transfer in 3-hydroxyflavones [13] and dissociation of phosphate esters [14].…”

Section: Introductionmentioning

confidence: 74%

Excited state substituent constants: to Hammett or not?

Sadlej-Sosnowska

Kijak

2011

Struct Chem

View full text Add to dashboard Cite

In this study, an answer has been sought to several questions: Can substituents' impact on the electronic properties of molecules in the excited singlet states be summed up by a set of substituent constants? Are the well known, ground state Hammett r constants practical for this purpose? To answer these questions, the potentials and charges on atoms of the functional groups in two classes of compounds, p-substituted benzoic acids and p-substituted nitrosobenzenes, were regressed against r p . It appeared that all correlations found in the ground state of the molecules also hold in the excited state, with lower correlation coefficients in the latter. An attempt has also been made to find a molecular characteristic which could be useful in a comparison of the acidic properties of benzoic acids (in gas phase) in the first excited and ground states.

show abstract

Section: Introductionmentioning

confidence: 74%

Excited state substituent constants: to Hammett or not?

Sadlej-Sosnowska

Kijak

2011

Struct Chem

View full text Add to dashboard Cite

show abstract

“…The substitution dependence of the speed and yield of photoisomerization was demonstrated by Zinth and co‐workers and could be used for optimization of HTI properties . Considering the polarity of the HTI molecule, electron‐donating and ‐withdrawing groups had an inverse effect on the photoisomerization speed, depending on the part of the HTI molecule where they were attached.…”

Section: Photochromism and Switching Mechanism Of Hti And Its Amino mentioning

confidence: 93%

“…The spectroscopic properties of HTI‐based photoswitches were established in recent years and a detailed reaction model of the molecular mechanism of the photochemical reactions Z → E and E → Z became available . This model describes both the reaction pathways and their intermediate states, and highlights an important feature of HTI: the ultrafast nature of the isomerization processes with a speed limit of about 1–2 ps that is triggered by near‐UV and visible light .…”

Section: Introductionmentioning

confidence: 99%

Light‐Switchable Peptides with a Hemithioindigo Unit: Peptide Design, Photochromism, and Optical Spectroscopy

et al. 2016

Self Cite

View full text Add to dashboard Cite

This Minireview focuses on the hemithioindigo photoswitch and its use for the reversible control of three-dimensional peptide structure and related biological functions. Both the general design aspects and biophysical properties of various hemithioindigo-based chromopeptides are summarized. Hemithioindigo undergoes reversible Z→E photoisomerization after absorption of visible light. The unique ultrafast switching mechanism of hemithioindigo combines picosecond isomerization kinetics with strong double-bond torsion after light absorption, making it the ideal tool for instantaneous modulation of biological structure. Various inhibitors and model peptides based on hemithioindigo are described that can directly regulate biological signaling or allow the fastest events in peptide folding to be studied. Finally, a diverse range of chromopeptides with photoswitchable β-hairpin structures based on azobenzenes, stilbenes, and hemithioindigo are compared to emphasize the unique properties of hemithioindigo.

show abstract

“…The introduction of electron‐donating substituents at the para ‐position of the sulfur atom in the thioindigo fragment allows circumventing this problem entirely, leading to photoswitches with vastly improved switching behavior. A methyl substituent in the para ‐position to the sulfur (HTI 4 ) leads to no significant shift in the absorption spectrum compared to 1 but a notable decrease in extinction. Similar to HTI 1 very high isomer yields are obtained in the PSS when using blue (405 nm, >80 % E isomer) and green (505 or 530 nm, >99 % Z isomer) light for irradiation.…”

Section: Figurementioning

confidence: 99%

Bistable Photoswitching of Hemithioindigo with Green and Red Light: Entry Point to Advanced Molecular Digital Information Processing

Kink

Collado

Wiedbrauk

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

Photoswitches reacting to visible light instead of harmful UV irradiation are of very high interest due to the mild and broadly compatible conditions of their operation. Shifting the absorption into the red region of the electromagnetic spectrum usually comes at the cost of losing thermal stability of the metastable state-the switch switches off by itself. Only recently have photoswitches become available that combine visible light responsiveness with high bistability. However, shifting the wavelengths for bistable photoswitching beyond 600 nm is still a great challenge without involving secondary processes such as two-photon absorption or sensitization. We present a simple hemithioindigo photoswitch that can efficiently be photoisomerized using green and red light while maintaining a high thermal barrier of the metastable state. This highly sought after properties allow for selective switching in a mixture of hemithioindigo dyes. In addition, protonation can be used as second independent input altering the light response of the switch and allowing construction of advanced molecular digital information processing devices. This is demonstrated by realizing a broad variety of logical operations covering combinational and sequential logic behavior. By making use of the protonation-induced loss of thermal bistability, a high security keypad lock could be realized, which distinguishes the sequences of three different inputs and additionally erases its unlocked state after a short time.

show abstract

The Hammett Relationship and Reactions in the Excited Electronic State: HemithioindigoZ/E-Photoisomerization

Cited by 76 publications

References 34 publications

Excited state substituent constants: to Hammett or not?

Excited state substituent constants: to Hammett or not?

Light‐Switchable Peptides with a Hemithioindigo Unit: Peptide Design, Photochromism, and Optical Spectroscopy

Bistable Photoswitching of Hemithioindigo with Green and Red Light: Entry Point to Advanced Molecular Digital Information Processing

Contact Info

Product

Resources

About