Carbazole-based D-pi-A molecules: Determining the photophysical properties and comparing ICT effects of pi-spacer and acceptor groups


Altinolcek N. , Battal A., Vardalli C. N. , TAVASLI M. , Yu H. A. , Peveler W. J. , ...More

JOURNAL OF MOLECULAR STRUCTURE, vol.1239, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 1239
  • Publication Date: 2021
  • Doi Number: 10.1016/j.molstruc.2021.130494
  • Title of Journal : JOURNAL OF MOLECULAR STRUCTURE
  • Keywords: Acceptor, Carbazole, Intramolecular charge transfer, pi-spacers, Solvatochromism, Stokes shift, INTRAMOLECULAR CHARGE-TRANSFER, SENSITIZED SOLAR-CELLS, SOLVENT POLARITY, ELECTROCHEMICAL PROPERTIES, TRANSPORT MATERIALS, ORGANIC-DYES, DERIVATIVES, FLUORESCENCE, DESIGN, BLUE

Abstract

4-(9'-Hexylcarbazol-3'-yl)benzaldehyde (Cz-Ph-CHO: 4 ) and 4-(9'-hexylcarbazol-3'- yl)benzylidenemalononitrile (Cz-Ph-CN: 5 ) were synthesised with the structure of D-pi-A,where carbazole, phenylene and formyl/dicyanovinyl groups act as electron donor (D), pi-spacer (pi) and electron acceptor (A) units, respectively. The thermal, electrochemical, optical and intramolecular charge transfer (ICT) properties of compounds 4 and 5 were investigated. Compounds 4 and 5 , in particular their ICT behaviour, were also compared with the closely related structure, 2-(9'-hexylcarbazol-3'-yl)-5-pyridinecarbaldehyde (Cz-Py-CHO: 7 ). For the purpose of tuning chemical structure to obtain targeted properties, electrochemical data and absorption and emission measurements suggest that the dicyanovinyl unit in compound 5 is a better acceptor than formyl in compound 4, and that pyridine in compound 7 is a better pi-spacer than benzene in compound 4 , in exerting ICT characteristics such as fluorosolvatochromism and Stokes shifts. (C) 2021 Elsevier B.V. All rights reserved.