Über Orceinfarbstoffe, V. IR‐ und UV‐Spektren Hydroxy‐ und Amino‐Substituierter Phenoxazone

Abstract

Es wird an mehreren Hydroxy‐ und Amino‐phenoxazonen und ihren Acetaten gezeigt, daß Phenoxazone im IR‐Spektrum zwischen 6.0 und 6.5 μ drei charak‐teristische Schlüsselfrequenzen besitzen. Die Verschiebung der längstwelligen Bande im sichtbaren Spektrum dieser Verbindungen mit Säure und Alkali hängt von der Stellung der Hydroxy und Aminogruppe am Phenoxazon‐Grundgerüst ab. Sie ist für eine Substitution in 7‐Stellung besonders charakteristisch und kann mit dem Auftreten mesomerer Ionenstrukturen in bestimmten ph‐Bereichen gedeutet werden. Das chromophore Grundgerüst von allen Orcein‐komponenten wird spektroskopisch aufgeklärt.

Organic dyes in illuminated manuscripts: a unique cultural and historic record

“…The excitation spectrum displays a structured band, with a maximum at ca 574 nm and a shoulder at 550 nm (table 5). Considering that the absorption maxima values published by Musso & Matthies [32] for α-aminoand α-hydroxy-orceins, in basic methanolic solutions, were 550-560 nm and 574 nm, respectively, we can propose that it is the α-hydroxy-orcein that is contributing to the maxima observed at 570 nm (table 2). The 574 nm maximum is also in agreement with the 572 nm value published for water (basic pH) [37].…”

“…(It was not clear if the percentage refers to the weight of the extract 'orcein' mixture or to the total lichen weight.) The central rings depicted in table 1 were shown to be the main chromophores and their UVvis spectra were not relevantly influenced by the phenyl/methyl substituents [32]. It was also determined that litmus, an acid-base indicator extracted from the same lichen species by a similar process, is essentially based on 7-hydroxy-2-phenoxazone chromophores assembled in a polymeric structure [31] (table 1).…”

“…In 1957, Hans Musso and Hans-Georg Matthies provided a full comparative analysis of the main chromophores isolated from orcein lichens, based on infrared and UV-vis spectra [32]. This work would be further expanded in the 1961 Angewandte Chemie paper [33], which appeared in an English translation in 2003 [31].…”

Azine Dyes

“…Hydroxy-and aminophenoxazones exhibit characteristic key bands between 6.0 and 6.5 mm in the IR spectrum [229]. In nature, they are present as orceine dyes in lichens [230].…”

Azine Dyes

“…Hydroxy-and aminophenoxazones exhibit characteristic key bands between 6.0 and 6.5 mm in the IR spectrum [229]. In nature, they are present as orceine dyes in lichens [230].Aminophenoxazone dyes are suitable for dyeing textile material made from polypropylene [231].…”