ChemInform Abstract: Competitive Occurrence of Homolytic N—O and Heterolytic C—O Bond Cleavage in Excited‐State 1‐(Arylmethyloxy)‐2‐pyridones.

Abstract

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

1-(Arylmethyloxy)anthracenes: how substituents affect their photoreactivity and ability to initiate radical and cationic polymerizations

“…If a chargetransfer interaction in the excited state controls this photoreactivity, the reactivity order for 1a-c demonstrates that the substituted naphthyl group acts as an electron donor. As an excited-state bichromophoric interaction should be directly reflected in the emission behavior of a given molecule, 15 the fluorescence spectra of methoxy-substituted derivatives 1c-g were measured (Figures 4 and 5). Clearly, there are no significant differences in the maximum fluorescence wavelength and intensity of these derivatives in both toluene and 1,2-dimethoxyethane, suggesting a minor contribution of the above-described excited-state interaction to photoreactivity.…”

“…6,7,14 A systematic study of the photoreactivity of O-substituted anthracene-9-methanol derivatives in methanol revealed that in the singlet excited state, an intramolecular charge-transfer interaction assisted in the heterolytic CH 2 -O bond cleavage to generate ion and radical pairs. 15 Therefore, these derivatives are good candidates for a novel hybrid-type photoinitiator that does not require halogen or metal. Although O-acyl anthracene-9-methanol functioned as a photoinitiator for the radical polymerization of styrene (St), it induced the cationic polymerization of cyclohexene oxide (CHO) to only a minor extent.…”

“…17 There was a decreased ability to initiate cationic photopolymerization of CHO, thus owing to the weak absorption of the cyano-substituted naphthol chromophore at wavelengths greater than 320 nm. 17 Considering the strong absorption of the anthracene chromophore at these wavelengths, 7,15 we designed the 1-arylmethyloxyanthracene photoinitiator 1 shown in Figure 1. Furthermore, to develop an efficient hybrid photoinitiator, we closely examined the effect that structural changes have on the ability of the initiator-derived reactive species to initiate polymerization.…”