Study Of The Preparation And Photoinitiating Activity Of Arene-Iron Salts With Alkoxyl Group And Halides

In this paper, using the ligand exchanging reactions of ferrocenewith different arenes, several cationic photoinitiators were synthesized including [Cp-Fe-anisole]+(Ⅰ,Ⅱ), [Cp-Fe-diphenylether]+(Ⅲ,Ⅳ), [Cp-Fe-1,4-diethoxybenzene]+(Ⅴ), [Cp-Fe-chlorobenezene]+(Ⅵ). Among them, [Cp-Fe-1,4-diethoxybenzene]+PF6-(Ⅴ) is an unreported compound.The ligand exchanging reaction conditions were examined. The reaction of ferrocene with long chain alkoxylbenzene were studied and the probable reaction mechanism was proposed. It was found that the result of this reaction is [Cp-Fe-phenol]+ salt. The reaction of ferrocene with phenyl halides were also studied and found that the product of ferrocene with bromobenzene is [Cp-Fe-benzene]+ salt. The UV-Vis absorption spectra and photolysis of arene-Cp iron salts in CH2Cl2 were studied. The light absorption above 300nm caused by d-d transition of arene-Cp iron salts make them suitable with high pressure Hg lamp which is usually used in the photo-curing. Compared with [Cp-Fe-benzene]+ salt, by introducing alkoxyl group to benzene, the molar extinction coefficients of absorption at 300-400nm raise nearly 2 times and the absorptions move to long wavelength about 10nm. Arene-Cp iron salts synthesized in this paper all can initiated the polymerization of epoxides effectively. The cuing rate of cycloaliphatic epoxide ERl-4221 is quickest and that of glycidylether EPON-812 is slowest. The order of initiating ERL-4221 is as following: Ⅰ(273 mJ·cm-2)<Ⅲ(304.5 mJ·cm-2)<Ⅵ(388.5 mJ·cm-2)<Ⅴ(553 mJ·cm-2)<Ⅳ(847 mJ·cm-2)<Ⅱ(1239 mJ·cm-2). Organic peroxide BPO could sensitize the photoinitiating activity of arene-iron salts Ⅰ, Ⅱ, Ⅲ , Ⅳ , Ⅴ, Ⅵ.The investigation on the physically mechanical properties of cured materials showed that the arene-iron salts with alkoxyl group have good solubility and the compatibility of epoxy ERL4221 and E44 can be improved.