ABSORPTION SPECTRA OF CAROTENOIDS; STRUCTURE OF VITAMIN A₂

Ultraviolet Absorption of Steroids.

“…Where a steroid triene is composed of a heteroannular and a homoannular system as in 2,4,6-cholestatriene, the base value for the homoannular diene is used. The principal absorption band of heteroannular polyenes can be calculated (124) by equation 1 and that of homoannular polyenes by equation 2.…”

The synthesis characterization of historical novel azo pigments: implications for conservation science

“…The ease of synthesis of a series of pigments with a wide variety of aromatic substituents (alkyls, halides, nitro, alkoxy, cyano) in a variety of positions on the phenyl ring allows us to observe their effect on color via reflectance spectra, a fundamental question of pigment synthesis. Over the years a number of empirical attempts have been made to rationalize and quantify the substituent effect, most well-known are the Woodward Fieser rules [11][12][13]. However, these do not include -N=N-(azo) linkages, and all deal with determining the peak in the ultraviolet-visible spectroscopy, not an edge (vide supra).…”

Chemical Analysis of Pigment Produced by Haloalkalotolerent Bacteria Paracoccus Beibuensis Sl2

“…Carotenoids that contain polyene system of 10 or 11 double bonds and shows three banded absorption spectra, in which the band of maximum intensity is located at an intermediate distance from the other two bands, thus form broad bands having fine details of a shoulder. 13 According to Britton, 3 conjugated ketocarotenoids such as canthaxanthin, astaxanthin and echinenone, the spectrum consists of broad single maximum having no defined structure. The acetone extract of pigment was analyzed by spectrophotometer within range 400-600 nm.…”