Synthesis and Optical Properties of Aqueous Soluble Indolylfulgimides

Abstract

Three novel aqueous soluble fulgimides, trifluoromethyl carboxylic acid indolylfulgimide 4, dicarboxylic acid indolylfulgimide 5, and carboxylic acid indolylfulgimide 6, were synthesized. Both 4 and 5 can switch back and forth between open and closed forms upon illumination with specific wavelengths of light, while 6 can only switch from the closed form to the open form. In sodium phosphate buffer (pH 7.4) at 37 °C, an unusual hydrolysis of the trifluoromethyl group of the closed form of 4 resulted in 5 which has an additional carboxylic acid group. The closed form of 5 was further decarboxylated to generate 6 which was not photochromic. In buffer, the open form of 4 degraded 20% after 10 days while the closed form of 4 was converted to 5 rapidly. In buffer, both leeswj@fiu.edu. Supporting Information Available: 1 H and 13 C NMR spectra of compounds 4, 5 and 6. This material is available free of charge via the Internet at

Synthesis and Characterization of Photochromic Copolymers Containing 3-Indolylfulgides/Indolylfulgimides

“…The hydrolyzed 3Z-co-PAA exhibited a hypsochromic shift of 8 nm relative to the original 3Z-co-PAA, which is less compared to the water soluble fulgimides in a previous report. 33 As expected, replacing the CF 3 group on the bridging position of fulgimide with a CH 3 group increased stability of 5-co-PAA in aqueous solutions, and there was no corresponding hydrolyzed form observed.…”

“…2,20,28 To make the data comparable, the thermal stability of fulgimide 3 was tested in toluene at 80 °C, which is the same condition used in the previous research. 2,33,34,82 Both 1 H NMR and UV-Vis spectroscopy were used to measure the thermal decomposing of fulgimide…”

“…The observation is consistent with previous studies which pointed out that fulgimides have relatively lower quantum yields (longer cycling times) in aqueous solutions. 31,33,34 The copolymers degraded at least twice as fast in the acid solution (acetate buffer)…”

“…Similar with linear copolymer 2C-co-PAA in Chapter 5, the closed form copolymer 3C-co-PAA hydrolyzed in aqueous solution, probably because the CF 3 fulgimide were rapidly converted to a carboxylic acid fulgimide in aqueous solutions as described in a previous report. 33 The resulting hydrolyzed copolymers were also photochromic. The thermal and photochemical stabilities of hydrolyzed 3-co-PAA were studied …”

“…These fulgimides with a pendant hydrophilic group can be dissolved not only in organic solutions but also in aqueous solutions. 33,34 The ability to be aqueous soluble will make the fulgimides more practical for applications in biological systems.…”