series of push-pull butadiene dyes (new merocyanine dyes) containing 3,6-bis(dimethylamino)fluorenylidene, thioxanthenylidene, or 10-(9-xanthenylidene)-9(10H)-anthrylidene chromophore was easily synthesized from the corresponding 1,1-diaryl-2-propyn-1-ol systems. Their absorptionspectralproperties were examined and the relationship between their light absorptionproperties and chemical structures is
Among other photoinitiating systems, aromatic ketone based compounds have been largely exploited as photoinitiators (PIs). However, none of these compounds efficiently absorb above 420 nm. The search of novel architectures of Pis for getting an important red shift of the absorption is crucial for the use of visible lights for polymer synthesis. Novel bifunctional dyes derived from the Michler's ketone structure are proposed here as photoinitiators for the free radical polymerization of acrylates and the cationic polymerization of epoxides upon exposure to 457, 473, and 532 nm laser diodes and even to a green LED bulb at 514 nm. Excellent polymerization profiles are obtained. These original dyes exhibit a push-pull molecular character for a remarkable covering of the visible lights. The formation of the radicals and the ions in the two- and three-component photoinitiating systems is described and the initiation steps are discussed.
Easy entry to donor/acceptor butadiene dyes through a MW-assisted InCl3-catalyzed coupling of propargylic alcohols with indan-1,3-dione in water
作者:Javier Francos、Javier Borge、Josefina Díez、Sergio E. García-Garrido、Victorio Cadierno
DOI:10.1016/j.catcom.2014.07.028
日期:2015.3
In this contribution, the high-yield preparation and optical properties of some donor-acceptor butadiene dyes, generated by coupling of different 1,1-diaryl-2-propyn-1-ols with indan-1,3-dione, are presented. The reactions, which involve the initial Meyer–Schuster rearrangement of the aromatic alkynols and subsequent condensation of the resulting enals with the β-dicarbonyl compound, proceeded cleanly