Boronic acid azo dyes

Lakowicz has also prepared boronic acid azo dye molecules 41 and 42 in which direct conjugation with the boron center is possible. In particular, the azo dye 42 produces a visible color change from yellow to orange at pH 7. 

Boron complex azo dyes have also been reported. These include solvent soluble boron complexes, such as the red dye (32) used for dyeing polyester and coloring plastics25,26 and water-soluble dyes for the detection of boron (as boric acid) by a color change27 (Scheme 5). 

James and coworkers [38] have synthesized an azo dye molecule with boronic acid, receptor 40, which can act as a colorimetric sensor for detection... 

Egawa has taken a novel approach to use the N-B interaction to influence the color of azo dyes 47 and 48 on saccharide binding. The ortho boronic acid systems show substantial changes in the UV-vis absorption spectra on saccharide binding. The same system has also been attached to a poly(ethyleneimine) polymer. ... 

Villanueva-Rodrfguez M, Hemandez-Ramrrez A et al. (2009) Enhancing the electrochemical oxidation of acid-yellow 36 azo dye using boron-doped diamond electrodes by addition of ferrous ion. J Hazard Mater 167 1226-1230... 

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