ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Phthalides and 1,3-indandiones. XX. 2-(p-Halophenyl)-5-azaindan-1,3-diones as acid-base indicators

P. Hrnčiar and D. Zacharová

Komenský University, Bratislava

Abstract: cf. CA 63, 5616d. The absorption spectra of title compds. (halogen = F, Cl, or Br) were studied in visible and uv regions as a function of pH. The predominating forms appear to be Ia and Ib at pH 1.2-4.7 and 5.8-12.3, with absorption max. at 515 and 460 mμ, resp. The sharp color change from violet to orange-yellow at pH 4.7-5.8 enables these compds. to be used as acid-base indicators similar to Congo red. A still better color change, from violet-blue to green, is obtained in the presence of methylene blue.

Full paper in Portable Document Format: 204a261.pdf (in Slovak)

Chemical Papers 20 (4) 261–266 (1966)