2-(1,1-Dicyanomethylene)rhodanine-Functionalized Oligothiophenes: A Structure-Property Investigation of / Photoisomerization Behavior.

A series of oligothiophenes singly and doubly functionalized with dicyanorhodanine (RCN) units have been investigated to understand their / photoisomerization behavior upon structural modulation. Monotopic RCN target molecules (-) were designed to observe the consequences of π-conjugation, solubilizing group substitution, and formylation of the thiophene units. In all cases, the isomer is obtained from synthesis as the thermodynamically stable isomer, whereas the isomer is achieved through selective irradiation (including red light, λ = 628 nm) as a / mixture in solution.

Thin-Film Morphology and Optical Properties of Photoisomerizable Donor-Acceptor Oligothiophenes.

It was recently reported that the most popular electron-accepting units introduced to π-conjugated oligomers studied for organic photovoltaic applications are susceptible to unwanted and even destructive photochemical reactions. The consequences of / photoisomerization of the popular 2-(1,1-dicyanomethylene)rhodanine (RCN) unit on the optical and morphological properties of a homologous series of RCN-functionalized oligothiophenes are studied here. Oligomers consisting of one, two, or three thiophene units were studied as pure isomers and with isomer compositions of 25, 53, and 45%, respectively, for / mixtures.

Synthesis and Evaluation of 3-Halobenzo[]thiophenes as Potential Antibacterial and Antifungal Agents.

The global health concern of antimicrobial resistance has harnessed research interest to find new classes of antibiotics to combat disease-causing pathogens. In our studies, 3-halobenzo[]thiophene derivatives were synthesized and tested for their antimicrobial activities using the broth microdilution susceptibility method. The 3-halo substituted benzo[]thiophenes were synthesized starting from 2-alkynyl thioanisoles using a convenient electrophilic cyclization methodology that utilizes sodium halides as the source of electrophilic halogens when reacted along with copper(II) sulfate.

Photoisomerization of dicyanorhodanine-functionalized thiophenes.

π-Conjugated oligomers functionalized with the popular dicyanorhodanine (RCN) electron acceptor are shown to be susceptible to photo-induced / isomerization. The stereochemistry of two model RCN-functionalized thiophenes is confirmed by single crystal X-ray analysis and 2D NMR, and shown to be the thermodynamically stable form. Relative energies, / configurations, and conformational preferences are modelled using density functional theory (DFT).

Iodocyclization in Aqueous Media and Supramolecular Reaction Control Using Water-Soluble Hosts.

Iodocyclization of 2-alkynylanisoles is an efficient route for synthesizing substituted benzofurans. Reaction efficiency with copper(II) sulfate and sodium iodide in an aqueous slurry under mild conditions is a manifold higher than in organic solvents. Water-soluble hosts of the cyclodextrin family solubilize the compounds in aqueous media and affect the reaction efficiency through conformation control and steric interactions.

Sodium halides as the source of electrophilic halogens in green synthesis of 3-halo- and 3,-dihalobenzo[]thiophenes.

A convenient methodology for the synthesis of mono- and di-halogenated benzo[]thiophenes is described herein, which utilizes copper(II) sulfate pentahydrate and various sodium halides in the presence of substituted 2-alkynylthioanisoles. The proposed method is facile, uses ethanol as a green solvent, and results in uniquely substituted benzo[]thiophene structures with isolated yields up to 96%. The most useful component of this methodology is the selective introduction of bromine atoms at every available position (2-7) around the benzo[]thiophene ring, while keeping position 3 occupied by a specific halogen atom such as Cl, Br or I.

Green Synthesis of Halogenated Thiophenes, Selenophenes and Benzo[]selenophenes Using Sodium Halides as a Source of Electrophilic Halogens.

Herein, we report the first synthesis of chlorinated benzo[]selenophenes via environmentally friendly electrophilic chlorocyclization reaction using "table salt" as a source of "electrophilic chlorine" and ethanol as a solvent. In addition, the synthesis of diverse halogenated heterocycles, including 3-chloro, 3-bromo and 3-iodo thiophenes, selenophenes, and benzo[]selenophenes was successfully accomplished under the same environmentally benign reaction conditions. This methodology has several advantages over other previously reported reactions as it employs simple starting compounds, an environmentally friendly solvent, ethanol, and non-toxic inorganic reagents under mild reaction conditions, resulting in the high product yields.