A DFT Study on Push-Pull (Amino-Nitro) Fulminenes and Hexahelicenes

TÜRKER B. L., Bayar C. C., Balaban A. T.

POLYCYCLIC AROMATIC COMPOUNDS, vol.30, no.2, pp.91-111, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 30 Issue: 2
  • Publication Date: 2010
  • Doi Number: 10.1080/10406631003756005
  • Journal Name: POLYCYCLIC AROMATIC COMPOUNDS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.91-111
  • Keywords: hexahelicenes, fulminenes, push-pull (donor-acceptor) groups, DFT, NICS(0), SEMIEMPIRICAL METHODS, ABSOLUTE HARDNESS, FREE-RADICALS, PI-ELECTRONS, CIRCULAR-DICHROISM, CHEMICAL-SHIFTS, AROMATICITY, RINGS, OPTIMIZATION, PARAMETERS
  • Middle East Technical University Affiliated: Yes

Abstract

In order to investigate the steric and electronic effects of electron-donor (amino) and -acceptor (nitro) substituents on hexahelicene and fulminene (isomeric and isoarithmic compounds), sixteen different types of terminal-amino-nitro hexahelicenes (H1-H16) and fulminenes (F1-F16) have been designed and investigated theoretically by the DFT method at B3LYP/6-31G(d) level. Besides electronic and thermodynamic properties, aromaticities (via NICS(0) calculations) have also been discussed for the above sets of terminal-rings-substituted hexahelicenes and fulminenes having 16 isomers each. Steric hindrance, seen enhanced in Hn structures, affects the total energies and heat of formations. The quinonoid conjugation is a minor factor in determining the trends in ring aromaticity of the above structures.