Spectroscopic properties of violacein and related compounds: crystal structure of tetramethylviolacein

Abstract

Violacein and deoxyviolacein have been isolated from cultures of Alteromonas luteoviolacea. The violacein-type lactams (1) and lactones (3) have a merocyanine chromophore which was confirmed by the effects of substituents on the visible spectra and by HMO calculations. Using parameters derived from an X-ray crystal structure analysis of tetramethylviolacein, PPP calculations of the electronic spectra of violacein and isoviolacein derivatives showed good agreement with observed values.