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Upstream product

• 6165-68-0 thiophene boronic acid 
• 608-30-0 2,6-dibromoaniline 
• 193978-23-3 2-thiopheneboronic acid pinacol ester 

Relevant academic research and scientific papers

Chemical synthesis and characterization of polyaniline derivatives. substituent effect on solubility and conductivity

ABSTRACT Polyanilines have different macroscopic properties according to the substituent incorporated into their monomers. Being conducting polymers, one of these properties is conductivity, which may increase or decrease depending on the substituent and its position in the chain. This work is focused on the modification of aniline monomers, which characteristics will vary, enabling thus the effect of the substituent on the respective polymer to be studied. For this purpose monomers substituted with methoxy and bromine, which are commercially available, and thiophenes were prepared using Suzuki and Ullman reactions. It was found that all polymers have conductivities of the order of 10-6 S?cm-1 or less. This demonstrated the performed substitutions had a negative effect on conductivity (although would facilitate their use in solar cells) as compared to aniline (PANI). These modifications also improve the solubility of the respective polymers, as most were more soluble than PANI.

Control of Chain Walking by Weak Neighboring Group Interactions in Unsymmetrical Catalysts

A combined theoretical and experimental study shows how weak attractive interactions of a neighboring group can strongly promote chain walking and chain transfer. This accounts for the previously observed very different microstructures obtained in ethylene polymerization by [κ2-N,O-{2,6-(3′,5′-R2C6H3)2C6H3-Rfnet=C(H)-(3,5-X,Y-2-O-C6H2)}NiCH3(pyridine)], namely hyperbranched oligomers for remote substituents R = CH3 versus high-molecular-weight polyethylene for R = CF3. From a full mechanistic consideration, the alkyl olefin complex with the growing chain cis to the salicylaldiminato oxygen donor is identified as the key species. Alternative to ethylene chain growth by insertion in this species, decoordination of the monomer to form a cis β-agostic complex provides an entry into branching and chain-transfer pathways. This release of monomer is promoted and made competitive by a weak η2-coordination of the distal aryl rings to the metal center, operative only for the case of sufficiently electron-rich aryls. This concept for controlling chain walking is underlined by catalysts with other weakly coordinating furan and thiophene motifs, which afford highly branched oligomers with >120 branches per 1000 carbon atoms.

Synthesis of random copolymers of 2,6-di(thiophen-2-yl)aniline and 2,2'-(thiophen-2,5-diyl)dianiline with aniline and its evaluation in organic solar cells

The present work deals with copolymers synthesized by reacting aniline units or blocks with 2,6-di(thiophen-2-yl)aniline and 2,2'-(thiophen-2,5-diyl) dianiline monomers. Characterization by spectroscopic techniques such as FT-IR, UV-vis, 1H-NMR corroborated the formation of true copolymers. Synthesized products showed improved solubility and better photovoltaic efficiency than the respective homopolymers. The latter is due to the presence of a greater number of quinoid units, capable of promoting charge carriers generation. However, the low mobility of the charge carriers, that increases copolymers resistivity, would be responsible for an efficiency improvement of just one order of magnitude with respect to the homopolymers.