Halochrome Molekeln. 2. Mitteilung. Synthese und acidobasisches Verhalten substituierter 6,6-Diphenyl-6H-chromenoindole

Article abstract of DOI:10.1002/hlca.19800630518

Substituted 6,6-diphenyl-6H-chromeno<4,3-b>indoles are forming with acid ring-opened, intensely coloured diphenyl-indol-3-yl-carbenium salts.The preparation of these products is described and the UV/VIS.-spectra are discussed.An investigation of the halochromic properties is made by spetrophotometric determination of ε_pH*- and ε_Ho*-curves in buffered methanol/water solutions. pK*- and pK₀*-values respectively are calculated and suitability of substituted 6H-chromeno<4,3-b>indoles as chromogens in self-duplicating stationary is discussed.