A glance at violet LED sensitive photoinitiators based on the spiroxanthene scaffold

Abstract

International audienceA novel photoinitiator based on a spiroxanthene scaffold in the presence of an iodonium salt is proposed for the cationic ring-opening polymerization of a diepoxide, as well as for the free-radical polymerization of an acrylate upon violet LED exposure (385 and 405 nm). Good-to-excellent rates of polymerization and final conversions are obtained. These systems are characterized by a higher reactivity compared with that of anthracene/iodonium salt used as reference for cationic near UV polymerization. The addition of a poly(ionic liquid) improves the cationic polymerization profiles. The photochemical mechanisms are studied by steady-state photolysis, fluorescence, and electron spin resonance spin-trapping techniques. Molecular orbital calculations give an insight into the light absorption properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 4321

Rigidly Fused Spiro‐Conjugated π‐Systems

“…To enlarge the scope of spiro-fused compounds for electronics, Poriel et al developed spiro fluorene xanthene (SFX) derivatives 61 and 62 (Scheme 20) with remarkable PLQYs of 63 % and 91 %, respectively. [47][48][49] The Stokes shifts of both 61 and 62 compounds were 3 and 4 nm, respectively. In comparison with their 1 and 14 carbon equivalents (respectively), compounds 61 and 62 presented analogous gaps and frontier orbital energy levels, demonstrating that the primary properties of these systems are induced by their corresponding central cores.…”

“…To enlarge the scope of spiro‐fused compounds for electronics, Poriel et al. developed spiro fluorene xanthene (SFX) derivatives 61 and 62 (Scheme 20) with remarkable PLQYs of 63 % and 91 %, respectively [47–49] . The Stokes shifts of both 61 and 62 compounds were 3 and 4 nm, respectively.…”

Review on UV-Induced Cationic Frontal Polymerization of Epoxy Monomers

“…[ 88 , 89 , 90 , 91 , 92 ]. In addition, several new compounds have also shown broad visible light absorption in the cationic polymerization of epoxides, such as azahelicenes [ 93 ], rubrene [ 94 ], N -[2-(dimethylamino)ethyl]-1,8-naphthalimide [ 95 ], spiroxanthene [ 96 ], polyoxometalate [ 97 ], nanoparticles and ferrocenium salts [ 98 ], etc.…”

Fluorene–Carbazole-Based Porous Polymers by Photoinduced Electron Transfer Reactions

“…The photochemical interaction of the fluorene scaffold with iodonium ions was demonstrated by using various spectroscopy and laser flash photolysis studies. 43 It should be pointed out that the analogous reactions also occur in the electrochemical polymerization. 11−14 As the polymerization proceeds through several active sites, the formed polymers are highly conjugated and branched (Scheme 2).…”