Strong Charge-Transfer Chromophores from [2+2] Cycloadditions of TCNE and TCNQ to Peripheral Donor-Substituted Alkynes

✍ Scribed by Songhua Chen; Yongjun Li; Chao Liu; Wenlong Yang; Yuliang Li

• Book ID: 102829084
• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 551 KB
• Volume: 2011
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.201101009

✦ Synopsis

Abstract

Peripheral donor‐substituted N,N‐dimethyl‐4‐[(7‐nitrobenzo[c][1,2,5]thiadiazol‐4‐yl)ethynyl]aniline (1a), 4‐(benzo[c][1,2,5]thiadiazol‐4‐ylethynyl)‐N,N‐dimethylaniline (1b), and 4,4′‐{benzo[c][1,2,5]thiadiazole‐4,7‐diylbis(ethyne‐2,1‐diyl)}bis(N,N‐dimethylaniline) (2) were prepared by Sonogashira cross‐coupling reactions. Compounds 1a, 1b, and 2 subsequently reacted with tetracyanoethylene (TCNE) or 7,7,8,8‐tetracyanoquinodimethane (TCNQ) to afford the charge‐transfer chromophores 3–8. X‐ray crystallographic analysis revealed the nonplanarity of these donor–acceptor (D–A) chromophores. Cyclic voltammetry (CV) exhibited a multistep reduction wave. UV/Vis spectra and theoretical calculations identified efficient intramolecular charge‐transfer interactions. Moreover, scanning electron microscopy (SEM) showed the morphology transition and reconstruction process of 5 from 0D hollow nanospheres to 1D tubular microstructures.