Blue Electrofluorescence Properties of Furan–Silole Ladder Pi-Conjugated Systems

• Published in: Applied sciences Vol. 8; no. 5; p. 812
• Main Authors: Chen, Hui, Denis, Mathieu, Bouit, Pierre-Antoine, Zhang, Yinlong, Wei, Xinda, Tondelier, Denis, Geffroy, Bernard, Duan, Zheng, Hissler, Muriel
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 18.05.2018; Multidisciplinary digital publishing institute (MDPI)
• Subjects: Benzofuran; Biphenyl; Butadiene; Chemical bonds; Chemical Sciences; Chromatography; Density functional theory; Electrodes; Electroluminescence; Electron transport; Emitters; Emitters (electron); Fluorescence; Iodine; Laboratories; Molecular orbitals; NMR; Nuclear magnetic resonance; Optical properties; Organic chemistry; Organic light emitting diodes; Silicon tetrachloride; Palo Alto California; France; United States > US; China; OLED; π-conjugated systems; fluorescence; heterocycles
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app8050812

First of all, the σ*-π* hyperconjugation between the exocyclic Si-C bonds and the π* orbital of the butadiene moiety drastically lower the LUMO of the siloles, thus enhancing its electron transport ability [10]. [...]we recently reported on the preparation of ladder-benzofuran fused phospholes C (Figure 1) showing efficient electroluminescent properties in OLEDs if the compound C is diluted in a 4,4′-bis(2,2-diphenylvinyl)-1,1′-biphenyl (DPVBi) matrix [40]. Since Si-containing planar-π-conjugated systems (Figure 1B) and benzofuran fused-π-conjugated systems (Figure 1C) are highly efficient emitters, we decided to develop and study the properties of Si,O-ladder π-conjugated systems (Scheme 1) as potential efficient fluorescent emitters in OLEDs. [14] This might be due to the low reactivity of the dilithiated intermediate 1Li. [...]the procedure was modified to prepare compounds 4–6 from the reaction of 1Li with highly reactive and less bulky SiCl4. Density functional theory calculations (DFT) performed on compounds 2 and 4 at the B3LYP/6-311+G (d, p) level (Figure 3 and Table S3, Figure S3) [44] show that both the HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Occupied Molecular Orbital) are localized on the entire π-conjugated carbon framework with a contribution of σ*-π* in the LUMO. [...]the exocyclic groups linked to the Si atom can have an influence on the optical properties.