3377. Dithizone

Nomenclature

CAS number: 60-10-6; 760132-01-2 (E-form)
2-Phenyldiazenecarbothioic acid 2-phenylhydrazide; (phenylazo)thioformic acid 2-phenylhydrazide; diphenylthiocarbazone.
C13H12N4S; mol wt 256.33.
C 60.91%, H 4.72%, N 21.86%, S 12.51%.

Description and references

Prepn: E. Fischer, E. Besthorn, Ann. 212, 316 (1882). Use as an analytical reagent: A. Stock, E. Pohland, Angew. Chem. 39, 791 (1926); H. Fischer, ibid. 46, 442 (1933); 50, 919 (1937); Organic Reagents for Metals (Hopkins & Williams, 1934). Crystal structure: M. Laing, J. Chem. Soc. Perkin Trans. 2 1977, 1248. Conformation in soln: A. T. Hutton, H. M. Irving, Chem. Commun. 1981, 735. Monograph: Analytical Sciences Monograph No. 5 entitled “Dithizone”, H. M. Irving, Ed. (Chemical Society, London, 1977) 112 pp. Review: idem, Crit. Rev. Anal. Chem. 8, 321-405 (1980).

Chemical structure

Properties

Bluish-black cryst powder, mp 168° (dec). Insol in water. Sparingly sol in alc, freely in carbon tetrachloride, chloroform. Solns are not stable, but may be preserved by a layer of aq SO2.

Caution

Has caused glycosuria and ocular injury in exptl animals.

Use

Sensitive indicator reagent for several heavy metals, Cd, Co, Cu, Pb, and Hg; esp for the estimation of minute amounts of Pb.