10229. Nile Red

Nomenclature

CAS number: 7385-67-3
9-(Diethylamino)-5H-benzo[a]phenoxazin-5-one; Nile Blue A oxazone.
C20H18N2O2; mol wt 318.37.
C 75.45%, H 5.70%, N 8.80%, O 10.05%.

Description and references

Hydrophobic fluorescent and solvatochromic dye. Prepn: R. Mhlau, K. Uhlmann, Ann. 289, 90 (1896); J. F. Thorpe, J. Chem. Soc. 1907, 324. Solvent-dependent spectrophotometric properties: M. M. Davis, H. B. Hetzer, Anal. Chem. 38, 451 (1966) DOI. Spectrofluorometric studies of lipid interactions: P. Greenspan, S. D. Fowler, J. Lipid Res. 26, 781 (1985) PubMed. Solvatochromic and thermochromic properties: C. M. Golini et al., J. Fluoresc. 8, 395 (1998) DOI; N. Ghoneim, Spectrochim. Acta A 56, 1003 (2000) DOI PubMed. Use as a fluorescent probe of hydrophobic protein sites: D. L. Sackett, J. Wolff, Anal. Biochem. 167, 228 (1987) DOI PubMed; as a stain for low density lipoproteins: P. Greenspan, R. L. Gutman, Electrophoresis 14, 65 (1993) DOI PubMed; in detection of protein aggreagates: M. Sutter et al., J. Fluoresc. 17, 181 (2007) DOI PubMed; as an optochemical humidity sensor: I. Pellejero et al., Ind. Eng. Chem. Res. 46, 2335 (2007) DOI.

Chemical structure

Properties

Brown glistening plates from light petroleum, with faint green metallic reflex, mp 205° (Thorpe). Also reported as mp 192-193° (Greenspan, Fowler). Soly in acetone: 1 mg/ml; in n-heptane: 62 μg/ml; in water: <1 μg/ml. Partition coefficient at 4° (xylene/water): 210; (chloroform/water): 196; (n-heptane/water): 58. Absorption max in cyclohexane: 490, 512.5 nm; in acetone: 533 nm; in DMF: 541 nm; in ethanol: 550 nm; in formamide: 564 nm. Emission max in acetone: 615 nm; in DMF: 625 nm; in ethanol: 635 nm; in water: 665 nm.

Use

Polarity-sensitive fluorescent probe for lipids and hydrophobic protein domains.