Monobromoindigos: a new general synthesis, the characterization of all four isomers and an investigation into the purple colour of 6,6′-dibromoindigo

Autor:	Christopher J. Cooksey, Robin J. H. Clark
Rok vydání:	1999
Předmět:	Bromine Absorption spectroscopy Ft raman spectroscopy chemistry.chemical_element General Chemistry Purple colour Catalysis Indigo Characterization (materials science) symbols.namesake chemistry Materials Chemistry symbols Organic chemistry Molecule Physical chemistry van der Waals force
Zdroj:	New Journal of Chemistry. 23:323-328
ISSN:	1369-9261 1144-0546
Popis:	A new general synthesis of all four isomers of monobromoindigo is outlined, the synthesis of 4-, 6- and 7-bromoindigo being described for the first time. All four monobromoindigos as well as indigo and the historically important 6,6′-dibromoindigo (Tyrian purple) have been characterized by 1H NMR spectroscopy of their N,N′-bis(trifluoroacetyl) derivatives, by FT-IR and FT Raman spectroscopy, and by their visible absorption spectra in solution and as dyes on wool. The absorption spectra of the dyes have been calculated by molecular mechanics (MM+) and semiempirical MO (PM3) methods. The purple colour of wool dyed with 6,6′-dibromoindigo is thought to be due to the interaction of the π systems of two parallel molecules that are brought together by van der Waals attraction between the bromine atoms.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::d23d6c6e3a681f8c9aa7bdf72f2aaf7f https://doi.org/10.1039/a808562e Zobrazit plný text záznamu