Synthesis and optoelectronic properties of phenylenevinylenequinoline macromolecules

Abstract

A series of 3, 5 and 7 quinoline terminated arylenevinylene oligomers was selectively synthesized by applying two repetitive reactions at each cycle of oligomerization: a Wittig and Pd Heck cross-coupling. Oligomers were characterized by 1 H and homo-J-resolved, DEPT-135, APT, 13 C NMR and MALDI-TOF spectrometry.A detailed characterization of the oligomers was performed by UV-Vis, static-dynamic fluorescence and Z-scan spectroscopy. The HOMO and LUMO levels were determined by cyclic voltammetry and compared with the theoretical ones. Effective conjugation is attained for the pentamer, whilst the molecular structure of the heptamer shows a pronounced torsion of the phenylenevinylene segment disrupting the degree of conjugation as revealed by theoretical simulation of the oligomer geometry. Furthermore, the theoretical simulation shows that the HOMO-LUMO frontier orbitals are mainly localized in the phenylenevinylene structure, while in the quinolines the spatial distribution is only located at the CQN-group without any appreciable contribution of the adjacent phenyl group. The pentamer is the most fluorescent oligomer with a quantum yield in solution of f = 0.62-0.68 depending on the solvent and a fluorescence lifetime of 1.07-1.28 ns, making this oligomer suitable for optoelectronic devices.

Mechanosynthesis of Photochromic Oligophenyleneimines: Optical, Electrochemical and Theoretical Studies

“…Therefore, more studies should be performed to verify if these compounds present electrochromic effect. Finally, the electrochemical parameters were used to calculate their band gap energies (Eg (EC) ) by using the reported procedure [ 32 ]. The data are summarized in Table 2 .…”

“…However, the reduction potential obtained for DAFCHO is relatively lower (−1.26) than that exhibited by FDACHO (−1.10). According to previous studies [ 32 ], the introduction of the imine groups into the conjugated structure promotes more active sites for the reduction process, because of unbonded pairs of nitrogen electrons, but the aldehyde groups promotes the oxidation process.…”

Functionalized benzazines as luminescent materials and components for optoelectronics

“…These compounds are highly luminescent in CHCl 3 , THF and toluene. 30 A push-pull effect is only observed for compound 28a, whereas for 28b and 28c no significant effects of the quinoline fragment are observed neither spectroscopically, electrochemically nor theoretically. Compound 28a is the most emissive (in CHCl 3 λ em = 499 nm Φ F = 0.64) making it suitable for optoelectronic devices.…”

“…29 These derivatives can be also obtained in two steps from 2quinolinecarboxaldehyde (8) (Scheme 2, bottom reaction). 30 The first step consists in a Wittig reaction with methyltriphenylphosphonium bromide to obtain 2-vinylquinoline 9. This intermediate can be involved in a palladium catalyzed Heck cross-coupling reaction with aryliodides to yield (E)- 2-Styrylquinoline derivatives 12 can be also obtained from ortho-iodo anilines 10 and 2trans-styryl propargyl alcohols 11 by domino synthesis initiated by a Sonogashira couping and concluded by a base catalyzed propargyl alcohol-enone isomerization (Scheme 3, top reaction).…”

Synthesis of Photochromic Oligophenylenimines: Optical and Computational Studies

“…[1]. In these materials, conjugated polymers and oligomers are generally used due to their optical and electrical properties [2]. Photochromism occurs when isomers which can participate in reversible transformations absorb at different wavelength by alternating irradiation with UV and visible light [3].…”