Fulgimide

Fuji print films, 19 282 Fujix Pictrography, 19 290 Fujix Pictrography 1000, 19 317-318 Fulgides, photochromic materials, 6 599 Fulgimides, photochromic materials,... 

In some cases, the formation of photochromic maleimides requires drastic conditions. Thus, hybrid meta and ipara derivatives 194 containing both fulgimide and diarylethene photochromic fragments were prepared in 61 and 75%, respectively, by refluxing amines 193 with anhydride 165 in ethanol under argon for 70 h in the presence of molecular sieves (06MI1, llEJO) (Scheme 57). 

However, the synthesis of meta and para derivatives 195, as well as 197, from fulgimide 196 requires even more drastic conditions. The reaction occurred only at high pressure (10 kbar) the yield of para-substituted photochrome 195 was 57% the yield of the meta isomer was 34% the yield of hybrid 197 was 11%. Hybrid product 199, in which the photochromic fragments are directly linked to each other by an N-N bond, was synthesized similarly (06MI1) from fulgimide 198 (Scheme 58). 

The corresponding imides (1.40), called fulgimides, are most readily synthesised by conversion of the fulgide into the succinamic acids by reaction with amines, followed by dehydration. Functionalisation of the anhydride can also be achieved by reaction of the fulgides with malononitrile in the presence of diethylamine and subsequent recyclisation with acetyl chloride to give (1.41) from the corresponding E-fulgide and (1.42) from the Z-isomer. 

Thanks to the fulgides succinic anhydride moiety, modification to obtain more sophisticated photochromic molecules has been easy. This chapter deals with imides (fulgimides), diesters (fulgenates), and some other derivatives, as well as fulgides themselves. 

Willner et al. also prepared fulgimide-modified (through lysine nitrogen) a-chy-motrypsin 30, with nine fulgimide molecules in one protein. 311 The modified protein was active towards esterification of N-acetylphenylalanine in cyclohexane. Together with the bioimprinting technique of the substrate, the rate of esterification could be accelerated by irradiation with UV light. 

Five years later, Gust s group [34] developed another triad incorporating a porphyrin (P) linked to a dithienylethene (DTE) and a fulgimide (FG) (Scheme 6). The main synthetic approach was still the Sonogashira coupling of dithienylethene and fulgimide-appended zinc porphyrin (FG-PZn-DTE). Trifluoroacetic acid-induced demetalation of FG-PZn-DTE produced FG-P-DTE in 57% yield. 

This molecule consisted of two photochromes a fulgimide and a dithienylethene. Both of them could isomerize with UV light from the open form to the closed form. And each photo-unit was thermally stable in either isomeric state. Moreover, the photoisomerization of fulgimide could efficiently transfer singlet excitation energy... 

Fulgides and fulgimides - potentially useful for information storage in erasable optical disks ... 

The first compound of the fulgide family developed by Heller et al was a succinimide which was called a fulgimide. The general formula is shown in compound 5. 

FULGIMIDE, ISOFULGIMIDE, FULGENATE, FULGENOID, AND DICYANOMETHYLENE DERIVATIVES OF FULGIDES... 

A wide range of aryl and heterocyclic fulgimides with structure 5 have been prepared. Their overall yields and melting points are summarized in Table 4.20. 

Table 4.20. Synthetic Overall Yield and Melting Point of Fulgimides 5...

A photochromic fulgimide can undergo a chemical reaction similar to that of the corresponding fulgide, as shown in Scheme 22. 

A type of donor-fulgimide-acceptor (D-F-A) molecule 69e (see Scheme 22) has been used to study intramolecular energy transfer. In this molecule, the fulgimide unit is a switch for energy transfer. By controlling the E or C form of the fulgimide molecule, an intramolecular energy transfer is possible, but the transfer mechanism cannot be determined definitely.91... 

Table 4.21. Quantum Yield of Photocyclization Reaction of Fulgides and Fulgimides in Solution and Polymer Matrix51 91...

Source Based on V, Deblauwe and G. Smets, Quantum yields of the photochromic reactions of heterocyclic fulgides and fulgimides, Makromol. Chem, 189, 2503-2512 (1988). 

The cyclized form of the a-isofulgimide 74 shows a large hypsochromic shift of its long wavelength absorption band compared with the cyclized forms of the fulgide, fulgimide, and p -isofulgimide.1... 

Is the excited state of fulgimide different from that of fulgide No more studies have been presented to date. 

J. Whittall, Fulgides and fulgimides— a promising class of photochromes for application, in Applied Photochromic Polymer System (C. B. McArdle, ed.), pp. 80-120, New York (1991). 

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