Synthesis and optoelectronic characterization of some triphenylamine-based compounds containing strong acceptor substituents

• Published in: Journal of luminescence 2014-09, Vol.153, p.5-11
• Main Authors: Grigoras, Mircea, Ivan, Teofilia, Vacareanu, Loredana, Catargiu, Ana Maria, Tigoianu, Radu
• Format: Article
• Language: English
• Subjects: Charge transfer; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Fluorescence; Intramolecular charge transfer interactions; Magnetic resonances and relaxations in condensed matter, mössbauer effect; Maxima; Metal ions; Nuclear magnetic resonance and relaxation; Oligomers; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Oxidation; Photoluminescence; Photophysical properties; Physics; Reduction; Tetracyanoethylene cycloaddition; Triphenylamine-ethynylene compounds; Voltammetry
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2014.02.032

Three novel triphenylamine-based compounds containing strong electron acceptor groups have been synthesized and their comparative photophysical properties are presented. These compounds were obtained by a two-step method: (i) triphenylamine compounds with one, two and three phenylacetylene arms were synthesized by Sonogashira reaction between iodine-substituted triphenylamines and phenylacetylene, followed by (ii) post-modification of these electron-rich alkynes by addition of the strong electron acceptor, tetracyanoethylene. Characterization of all oligomers was made by FTIR, 1H-NMR, UV–vis and fluorescence spectroscopy. A batochromic shifting of the UV and photoluminescence maxima was observed with the increase of the acceptor group number. The electrochemical behavior was studied by cyclic voltammetry. The cyclic voltammograms have evidenced that triphenylamine-phenylacetylene compounds undergo only oxidation processes while compounds modified with tetracyanoethylene show both oxidation and reduction peaks associated with donor and acceptor groups, respectively. The donor–acceptor compounds coordinate metal ions (i.e., Hg2+ and Sn2+) by cyano groups resulting in the decreasing of charge transfer band intensity, and they can be used as chemosensors. •Three triphenylamine-based ethynylene compounds were prepared by Sonogashira reaction.•Post-modification of ethynylene linkages by tetracyanethylene cycloaddition and retroconversion led to donor–acceptor compounds.•Photophysical properties of donor–acceptor oligomers were studied in different solvents.