Hockey-stick-shaped mesogens based on 1, 3, 4-thiadiazole: synthesis, mesomorphism, photophysical and DFT studies. Issue 14 (8th December 2017)

• Record Type: Journal Article
• Authors: Saha, Sandip Kumar; Deb, Jyotirmoy; Sarkar, Utpal; Paul, Manoj Kumar
• Is Part Of: Liquid crystals. Volume 44:Issue 14/15(2017)
• Page Start: 2203
• Page End: 2221
• Publication Date: 2017-12-08
• Subjects: Hockey-stick-shaped mesogen -- 1, 3, 4-thiadiazole -- photophysical -- thermal stability -- mesomorphism -- computational studies; Liquid crystals -- Periodicals; 548.905
• DOI: 10.1080/02678292.2017.1331269
• Languages: English
• ISSNs: 0267-8292

Abstract

ABSTRACT: New hockey-stick-shaped 2, 5-diphenyl-1, 3, 4-thiadiazole-containing mesogens have been designed and synthesised. These molecules possess 4-n-alkoxy chain at the elongated arm whereas and 4-n-butyloxy chain at the shorter arm of the molecule. The compounds are fluorescent and emission located in the violet to blue region with a large stoke shift observed in polar solvents. No substantial solvatochromic effect was found in the absorption maxima, but in the emission, a red shift was observed with increasing the solvent polarity. In the solid thin film, compounds emitted green light. The compounds having longer chain ( n > 8) exhibit SmA and SmC phase, while the compounds with shorter chain at one end of the molecule display nematic and SmC phase. The density functional theory study has been carried out to investigate the stable configuration and the influence of solvent on bond length, bond angle, bending angle, dipole moment, polarisability of the molecule. It also enables us to predict the possible reactive sites and effect of solvent on the chemical reactivity descriptors. Our study concludes that the molecule becomes more reactive in solvent compared to gas. The large voltage holding ratio confirms that this molecule may be used for active matrix display applications. Graphical Abstract: