The effects of cyclic terminal groups in 4-aminoazobenzene and related azo dyes. Part 3. Electronic absorption spectra of some monoazo dyes derived from N-phenylmorpholine, N-(phenyl)thiomorpholine, N-(phenyl)thiomorpholine 1,1-dioxide, and N-acetyl-N′-phenylpiperazine

Authors:

GHGeoffrey Hallas
Geoffrey Hallas
RMRichard Marsden
Richard Marsden
JHJohn D. Hepworth
John D. Hepworth
DMDonald Mason
Donald Mason

1 January 1986

journal article
research article
Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 2

No. 1,p. 123-126
DOI:10.1039/p29860000123

Abstract

Monoazo dyes containing a terminal morpholino group absorb hypsochromically in comparision with their piperidino counterparts as a result of electron withdrawal by the oxygen atom. Similar shifts are observed with related dyes possessing other γ-heteroatoms in the donor group. In acid solution, protonation takes place at the β-azo nitrogen atom (azonium tautomer) and at the terminal nitrogen atom (ammonium tautomer) to an extent which depends on the inductive effect of the γ-substituent.

The effects of cyclic terminal groups in 4-aminoazobenzene and related azo dyes. Part 3. Electronic absorption spectra of some monoazo dyes derived from N-phenylmorpholine, N-(phenyl)thiomorpholine, N-(phenyl)thiomorpholine 1,1-dioxide, and N-acetyl-N′-phenylpiperazine

Abstract

Keywords