N. Kuramoto, K. Natsukawa, K. Asao
1989
Citations
0
Influential Citations
29
Citations
Journal
Dyes and Pigments
Abstract
Abstract The synthesis and characterization of some deep-coloured squarylium dyes was studied with respect to the development of media in optical recording systems. The reaction of 3-ethyl-2-methylbenzothiazolium iodide and squaric acid in benzene/1-butanol gave 2,4-bis[(3-ethyl-2-benzothiazolylidene)methyl]-cyclobutadienylium-1,3-diolate (λ max 667nm) and its iodide adduct type compound as by-product. The latter was a new compound and had an absorption maximum at 796 nm. Similarly an iodide adduct of 2,4-bis[(3-ethyl-2-benzoselenazolylidene)methyl] cyclobutadienylium-1,3-diolate was also synthesized from 3-ethyl-2-methylbenzoselenazolium iodide and squaric acid. This compound had an absorption maximum at 815 nm, i.e. in the infrared wavelength region. Thus, these new dyes with an iodine atom and a butoxy group generally absorbed at a much longer wavelength (120–130 nm) than the corresponding parent dyes. The structures of the dyes is also discussed on the basis of IR and ESCA analyses.