Influence of Controlled Chirality on the Crystallization of Maleimide-Functionalized 3,4-Ethylenedioxythiophene (EDOT-MA) Monomers.

Conjugated poly(alkoxythiophenes) such as poly(3,4-ethylenedioxythiophene) (PEDOT) have attracted considerable interest for use in a variety of applications such as biomedical devices, energy storage, and chemical sensing. Functionalized versions of the 3,4-ethylenedioxythiophene (EDOT) monomer make it possible to create polymers with properties tailored for specific applications. The maleimide functional group shows particular promise due to the wide variety of chemical modifications that it can undergo. Here, we examine the role that control of the chirality of the maleimide (MA) substituent has on the crystal structure and crystallization of the EDOT-MA monomer. We describe a method for the synthesis of a homochiral (S) variant of EDOT-MA and compare its crystallography, morphology, and thermal properties to that of the (R,S) EDOT-MA racemic compound. The conformation of the EDOT-MA molecule was substantially different, with the molecules adopting an "L" shape in the homochiral crystal, while in the racemic crystals, they were more colinear. The thermal stability of the homochiral crystals (Tm = 128.6 °C) was slightly higher than the racemic ones (Tm = 102.8 °C). We expect these results to be important in better understanding the solid-state assembly of the corresponding polymers prepared from these monomers.

Synthesis of extended conjugated indolyl chalcones as potent anti-breast cancer, anti-inflammatory and antioxidant agents.

In the present investigation, synthesis of a series of extended conjugated δ-chloro-α-cyano substituted indolyl chalcones (5a-p) was accomplished by reacting 3-cyanoacetylindole 2 with 3-chloro-3-phenyl-propenal 4 in the presence of piperidine. The structural interpretations of newly synthesized compounds were based on chemical and spectroscopic evidences. Anti-tumor evaluation of the synthesized compounds in vitro against MCF-7 (breast carcinoma) cell line revealed that they possess high anti-tumor activities. Among them, compound 5e and 5a demonstrated excellent activity against breast carcinoma (GI50 <0.1 and 4µM respectively) as good as adriamycin (GI50 <0.1µM). The compounds were also screened against the normal Vero monkey cell line, which showed moderate selectivity against inhibition of cancer cells. The effect of extended conjugation on activity authenticated by comparing activity profile of compound 5a, 5i and 5m with their simple analogues. Among the synthesized compounds, 5i and 5l were found to be active anti-inflammatory agents in addition to having noteworthy antioxidant potential. These results suggest the possible use of these compounds for the design and development of novel anti-breast cancer agents.

Chemically Delaminated Free-Standing Ultrathin Covalent Organic Nanosheets.

Covalent organic nanosheets (CONs) are a new class of porous thin two-dimensional (2D) nanostructures that can be easily designed and functionalized and could be useful for separation applications. Poor dispersion, layer restacking, and difficult postsynthetic modifications are the major hurdles that need to be overcome to fabricate scalable CON thin films. Herein, we present a unique approach for the chemical exfoliation of an anthracene-based covalent organic framework (COF) to N-hexylmaleimide-functionalized CONs, to yield centimeter-sized free-standing thin films through layer-by-layer CON assembly at the air-water interface. The thin-layer fabrication technique presented here is simple, scalable, and does not require any surfactants or stabilizing agents.