Zur Kenntniss des Baues und der Bildung färbender Kohlenstoffverbindungen

Several stories from theoretical chemistry with some Russian flavor and implications for theorems of chemistry, vagueness of its concepts, fuzziness of its definitions, iconicity of its language, and peculiarities of its nomenclature

“…On the same grounds as in benzene one can identify π‐subsystems of a specific composition ( —almost integer; ) in other planar molecules as well observable spectrally. This sets the situation in the direct relation with the old fashioned, but very useful concept of chromophore giving to a molecule its color as proposed by the personage of Figure . We can consider an arbitrary set of orthogonal subspaces giving the complete space of those as a direct sum and check whether they satisfy “daltonistic” condition ( —almost integer; ) so that the physical quantities are “good quantum numbers” and, thus, the many‐electron state over which the averaging is assumed is at least approximately an eigenstate for the system of operators .…”

The Chemical Causes of Color

“…He suggested empirically that a colored molecule must contain an unsaturated group called a chromophore in order to exhibit color [32]. Some common chromophores are -N=N-, -C=C-, -C=O, and the phenyl group, although their presence does not necessarily give rise to color.…”

Introduction: The Evolution of Present-Day Dye Technology

“…The first real attempt to interpret the color of dyes in terms of their molecular composition was made by Witt in 1876. 5 By this time, structural chemistry had progressed to the stage where functional groups were well understood, and Witt considered that a dye molecule could be dissected into three components. Thus, there were benzene, or fused benzene, rings, and to these were attached simple unsaturated groups, e.g., -N02, -N N-, -C=O, which he called chromophores.…”