scholarly journals A bisazobenzene crosslinker that isomerizes with visible light

2012 ◽  
Vol 8 ◽  
pp. 2184-2190 ◽  
Author(s):  
Subhas Samanta ◽  
Harris I Qureshi ◽  
G Andrew Woolley
Keyword(s):  
Visible Light ◽  
Thermal Relaxation ◽  
Bright Light ◽  
Large Change ◽  
Light Sources ◽  
Functional Changes ◽  
End Distance ◽  
End To End ◽  
Azobenzene Derivatives

Background: Large conformational and functional changes of azobenzene-modified biomolecules require longer azobenzene derivatives that undergo large end-to-end distance changes upon photoisomerization. In addition, isomerization that occurs with visible rather than UV irradiation is preferred for biological applications. Results: We report the synthesis and characterization of a new crosslinker in which a central piperazine unit links two azobenzene chromophores. Molecular modeling indicates that this crosslinker can undergo a large change in end-to-end distance upon trans,trans to cis,cis isomerization. Photochemical characterization indicates that it does isomerize with visible light (violet to blue wavelengths). However, the thermal relaxation rate of this crosslinker is rather high (τ½ ~ 1 s in aqueous buffer at neutral pH) so that it is difficult to produce large fractions of the cis,cis-species without very bright light sources. Conclusion: While cis-lifetimes may be longer when the crosslinker is attached to a biomolecule, it appears the para-piperazine unit may be best suited for applications where rapid thermal relaxation is required.

scholarly journals Sulfur and azobenzenes, a profitable liaison: straightforward synthesis of photoswitchable thioglycosides with tunable properties

2021 ◽  
Author(s):  
Jonathan Berry ◽  
Thisbe Lindhorst ◽  
Guillaume Despras
Keyword(s):  
Physicochemical Properties ◽  
Visible Light ◽  
Protein Interactions ◽  
Thermal Relaxation ◽  
Sulfur Oxidation ◽  
Coupling Method ◽  
One Pot ◽  
Molecular Systems ◽  
The Core ◽  
Azobenzene Derivatives

Azobenzene photoswitches are valuable tools for controlling properties of molecular systems with light. In particular, we have been investigating azobenzene glycoconjugates to probe carbohydrate-protein interactions and also to design photoresponsive glycomacrocycles with modulable chiroptical and physicochemical properties. To date, direct conjugation of glycosides to azobenzenes was performed by reactions providing target compounds in limited yields. We therefore sought for a more effective and reliable coupling method. In this paper, we report on a straightforward thioarylation of azobenzene derivatives with glycosyl thiols as well as other thiol substrates, increasing the scope of azobenzene conjugation. Importantly, red-shifted azoswitches that can be addressed with visible light were easily functionalized and challenging unsymmetrical conjugates were prepared in good yields via sequential or one pot procedures. In addition, we took advantage of the presence of the sulfide bridge to tune both photochromic and thermal relaxation properties of the core azobenzene via sulfur oxidation. Based on our photochemical investigations, we finally demonstrated orthogonal three-state photoswitching in mixtures containing two distinct azobenzene thioglycosides.

scholarly journals Sulfur and azobenzenes, a profitable liaison: straightforward synthesis of photoswitchable thioglycosides with tunable properties

2021 ◽  
Author(s):  
Jonathan Berry ◽  
Thisbe Lindhorst ◽  
Guillaume Despras
Keyword(s):  
Physicochemical Properties ◽  
Visible Light ◽  
Protein Interactions ◽  
Thermal Relaxation ◽  
Sulfur Oxidation ◽  
Coupling Method ◽  
One Pot ◽  
Molecular Systems ◽  
The Core ◽  
Azobenzene Derivatives

Azobenzene photoswitches are valuable tools for controlling properties of molecular systems with light. In particular, we have been investigating azobenzene glycoconjugates to probe carbohydrate-protein interactions and also to design photoresponsive glycomacrocycles with modulable chiroptical and physicochemical properties. To date, direct conjugation of glycosides to azobenzenes was performed by reactions providing target compounds in limited yields. We therefore sought for a more effective and reliable coupling method. In this paper, we report on a straightforward thioarylation of azobenzene derivatives with glycosyl thiols as well as other thiol substrates, increasing the scope of azobenzene conjugation. Importantly, red-shifted azoswitches that can be addressed with visible light were easily functionalized and challenging unsymmetrical conjugates were prepared in good yields via sequential or one pot procedures. In addition, we took advantage of the presence of the sulfide bridge to tune both photochromic and thermal relaxation properties of the core azobenzene via sulfur oxidation. Based on our photochemical investigations, we finally demonstrated orthogonal three-state photoswitching in mixtures containing two distinct azobenzene thioglycosides.

Visible-light-responsive lanthanide coordination polymers for highly efficient photocatalytic aerobic oxidation of amines and thiols

2021 ◽  
Author(s):  
Zhifen Guo ◽  
Xin Liu ◽  
Yan Che ◽  
Hongzhu Xing ◽  
Peng Chen
Keyword(s):  
Visible Light ◽  
Molecular Oxygen ◽  
Coordination Polymers ◽  
Aerobic Oxidation ◽  
Synthesis And Characterization ◽  
Lanthanide Coordination Polymers ◽  
Highly Efficient ◽  
Photocatalytic Reactions ◽  
Energy Issues

Development of visible-light-induced photocatalytic reactions using molecular oxygen as terminal oxidant is intriguing in view of the current environmental and energy issues. We report herein the synthesis and characterization of...

Self‐avoiding walks with span limitations. I. The mean square end‐to‐end distance

1980 ◽  
Vol 72 (4) ◽  
pp. 2702-2707 ◽  
Author(s):  
Ronnie Barr ◽  
Chava Brender ◽  
Melvin Lax
Keyword(s):  
Mean Square ◽  
End Distance ◽  
The Mean ◽  
End To End ◽  
Self Avoiding Walks
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