Neutral red

Structural formula
General
Surname	Neutral red
other names	3-Amino-7-dimethylamino-2-methylphenazine · hydrochloride; N 8, N 8,3-trimethyl-2,8-phenazine diamine monohydrochloride; Toluene red; CI Basic Red 5; CI 50040;
Molecular formula	C 15 H 17 ClN 4
Brief description	dark green odorless powder
External identifiers / databases
EC number	209-035-8
ECHA InfoCard	100.008.215
PubChem	11105
Wikidata	Q417515
properties
Molar mass	288.78 g mol −1
Physical state	firmly
Melting point	290 ° C (decomposition)
solubility	moderately in water (50 g l −1 at 25 ° C) and alcohol
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Neutral Red is a red phenazine - dye .

Extraction and presentation

Neutral red can be produced from N , N- dimethyl-4-nitrosoaniline and 2,4-diaminotoluene by adding hydrochloric acid .

properties

Neutral red dyes tannic cotton purple-red. The coloring is not lightfast . The dye is used as an indicator (color change from red to yellow at pH 6.8–8.0) and as a redox indicator for biological investigations such as determining cell viability using the neutral red test , as it is non-toxic.

Neutral red is uncharged from pH 13 to 7.5 and is yellow in color. Neutral red is membrane-permeable. From pH 7.4 and more acidic, the dye is protonated and takes on red color (pK _s 5.89). As a cation, neutral red is no longer able to penetrate membranes. It therefore accumulates in acidic compartments of cells (so-called ion trapping or ion trap ).

Individual evidence

↑ ^a ^b ^c ^d data sheet neutral red (CI 50040) (PDF) from Carl Roth , accessed on October 17, 2018.
↑ ^a ^b Entry on neutral red. In: Römpp Online . Georg Thieme Verlag, accessed on November 12, 2014.
↑ seilnacht.com: neutral , accessed on 16 October 2018
^ Microscopic technique: Romeis . Springer DE, 2010, ISBN 3-8274-2254-X , p. 44 ( limited preview in Google Book search).
↑ Hermann Kölbel: On the value and reaction mechanism of the neutral red test . Medical Microbiology and Immunology, 143 (4), February 1957, doi : 10.1007 / BF02156826 .

[Carl_Roth-1] ta sheet neutral red (CI 50040) (PDF) from Carl Roth , accessed on October 17, 2018.

[roempp-2] Entry on neutral red. In: Römpp Online . Georg Thieme Verlag, accessed on November 12, 2014.

[seilnacht.com-3] seilnacht.com: neutral , accessed on 16 October 2018

[Mikroskopische_Technik-4] Microscopic technique: Romeis . Springer DE, 2010, ISBN 3-8274-2254-X , p. 44 ( limited preview in Google Book search).

[5] Hermann Kölbel: On the value and reaction mechanism of the neutral red test . Medical Microbiology and Immunology, 143 (4), February 1957, doi : 10.1007 / BF02156826 .