Reichardt's dye (Betaine 30) is an organicdye belonging to the class of azomerocyaninebetaines. This dye is notable for its solvatochromic properties, meaning it changes color depending on the solvent in which it is dissolved. It has one of the largest solvatochromic effects ever observed,[1] with color varying across the entire visible spectrum. As a result, it gives striking visual results for chemical demonstrations.[2]
Reichardt's dye as seen in various solutions, in order of increasing polarity from left to right.
This chemical is named for Christian Reichardt [de], who developed it when working as a doctoral student in the lab of Karl Dimroth [de]. It is thus also sometimes called Dimroth–Reichardt dye. The names also sometimes refer to some close chemical analogs, in particular, the one having para substituted tert-butyl groups on the phenyl rings.[3]
^Osterby, Bruce R.; McKelvey, Ronald D. (1996). "Convergent Synthesis of Betaine-30, a Solvatochromic Dye: An Advanced Undergraduate Project and Demonstration". J. Chem. Educ. 73 (3): 260–261. Bibcode:1996JChEd..73..260O. doi:10.1021/ed073p260.
^Machado, Vanderlei Gageiro; Machado, Clodoaldo (2001). "An Easy and Versatile Experiment to Demonstrate Solvent Polarity Using Solvatochromic Dyes". J. Chem. Educ. 78 (5): 649–651. Bibcode:2001JChEd..78..649M. doi:10.1021/ed078p649.
^Reichardt, Christian (1994). "Solvatochromic Dyes as Solvent Polarity Indicators". Chem. Rev. 94 (8): 2319–2358. doi:10.1021/cr00032a005.
^Manfred A. Kessler; Otto S. Wolfbeis (January 1988), "An Improved Synthesis of the Solvatochromic Dye ET-30", Synthesis (in German), vol. 1988, no. 8, pp. 635–636, doi:10.1055/s-1988-27662
