22700-62-5Relevant academic research and scientific papers
Photoswitchable azobenzene-rhodamine tweezers for biosensing of Al3+ ions
Raman, Arunachalam,Augustine, George,Ayyadurai, Niraikulam,Easwaramoorthi, Shanmugam
, p. 9300 - 9305 (2018)
Dominant excited state photochemical deactivation over the radiative decay pathway of azobenzene enables this molecule to be non-fluorescent despite its rich π-conjugation. Partial or complete control over the photoisomerization reaction is indispensable in making this molecule fluorescent. To control the excited state properties of azobenzene, we have covalently coupled it with a spirocyclic rhodamine unit through a p-phenylmethanimine bridge. While the characteristic weak fluorescence and trans → cis photoisomerization of azobenzene have not been affected by spirocyclic rhodamine, selective Al3+ ion induced spirocyclic ring opening prevents the photoisomerization with a concomitant enhancement in fluorescence. This process is reversed by the addition of a F- ion. The occurrence of fluorescence resonance energy transfer (FRET) from azobenzene to rhodamine and light catalyzed spirocyclic ring opening reactions underscore that the azobenzene excited state can be altered without affecting its core structure. Indeed, the light catalyzed ring opening reaction helps to enhance the signal intensity, which would be advantageous in detecting Al3+ ions at lower concentrations. The applicability of the probe has been tested in prokaryotic and eukaryotic cell lines, where turn-on, intense fluorescence in the presence of Al3+ ions was observed.
Photoinduced, Direct C(sp2)?H Bond Azo Coupling of Imidazoheteroarenes and Imidazoanilines with Aryl Diazonium Salts Catalyzed by Eosin Y
Saba, Sumbal,Dos Santos, Caio R.,Zavarise, Bruno R.,Naujorks, Aline A. S.,Franco, Marcelo S.,Schneider, Alex R.,Scheide, Marcos R.,Affeldt, Ricardo F.,Rafique, Jamal,Braga, Antonio L.
supporting information, p. 4461 - 4466 (2020/02/25)
Herein, a greener approach to the eosin Y-Na2 catalyzed, C(sp2)?H bond azo coupling of imidazoheteroarene with aryl diazonium salts is described, under acid free conditions. This direct photoredox process resulted in the corresponding azo products in good to excellent yields. Besides, this new approach could also be applicable to anilines, which is a poorly reactive substrate by other methods. The main features of this reaction are that it provides high yields and is gram-scalable and applicable to biologically relevant imidazoheteroarenes and -anilines.
Studies on UV/Vis Absorption Spectra of Azo Dyes. XVIII. Substituent Effects on the Absorption Maxima of the n-->?* and ?-->?* Bands of 4-N,N-Diethylaminoazobenzenes
Haessner, Carmen,Mustroph, H.
, p. 493 - 498 (2007/10/02)
The spectra of 27 substituted 4-N,N-diethylaminoazobenzenes are determined.The band system can be separated by deconvolution into two Gaussian curves.The results so obtained show that the effects of substituents on n-->?* and ?-->?* transitions are similar and that electron withdrawing substituents in the phenylazo residue cause a bathochromic shift of both the n-->?* and the ?-->?* bands.
