Poly(arylene sulphide)s from masked bisthiophenols

A new approach to the synthesis of poly(arylene sulphide)s using masked bisthiophenols is presented. Bisthiophenols N-propylcarbamates can be purified easily by simple recrystallization and polycondensed directly with activated dihalide monomers in N-methylpyrrolidone in the presence of potassium bicarbonate

A facile synthesis of cysteine-based diketopiperazine from thiol-protected precursor

L-Cysteine is one of the most promising biomass-based building blocks with great potential applications. Herein, we report a versatile synthetic route to produce cysteine-based 2,5-diketopiperazine (DKP) with good yield from the thiol-ene click reaction of L-cysteine and commercially available acrylates, followed by dimerization of the amino acid intermediates. The achieved DKP diastereomers were successfully separated and fully characterized by spectroscopic methods. Moreover, the chiroptical property of DKP in the presence of various metal ions was investigated by circular dichroism spectroscopy. The potential application of the optically active cysteine-based DKP as a chiral probe for detection of silver ion in water has been demonstrated

Electrochemical and electrochromic properties of poly(ether naphthalimide)s and related model compounds

The electrochemical and electrochromic properties of poly(ether naphthalimide)s were studied and compared with related model compounds. The electroactive sites within the poly(ether naphthalimide)s were identified to be ketone and imide groups. The stepwise coloration process, colorless-red-dark blue corresponding to the neutral, radical anion and dianion species, was found to be related to the first reduction of the imide group and the second reduction of the ketone group. Based on this new polyimide a high-contrast switch between colorless and red or colorless and dark blue can be achieved and controlled electrically

Linear and hyperbranched reactive polymers containing diacetylene units with controllable refractive indices

A series of linear and hyperbranched poly(ether imides) containing diacetylene moieties are synthesized. Control of refractive index of the polymers can be achieved by varying the ratio imide/ether content. For the linear polymers the in-plane refractive index (nm) at 1550nm can be tuned between 1.5454 and 1.6313 by changing the ratio of two monomers. The maximum value is reached at 100 mol% of the imide monomer. The arm value can also be controlled between 1.5329 and 1.6283 by varying the monomer ratio. Decrease of birefringence was obtained by increasing the ether monomer content, from 1.25x10-2 to 3x10-3. The refractive indices of the hyperbranched polymers vary from 1.5646 to 1.6263 for nm and from 1.5584 to 1.6277 for nm. The chain branching causes a significant reduction of the birefringence to as low as 2x104 for polyTPPE and 6.2x10-3 for the hyperbranched poly(ether imides). UV curing of the thin polymeric films produces small changes in both nm and aim, lowering their value with an average of 5.5x10-3. Thermal curing produces coloration of the films, with an increase in refractive indices, both nm and arm