Theoretical investigation of steric effects on the S1 potential energy surface of o-carborane-anthracene derivatives

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Alkan F.

Turkish Journal of Chemistry, vol.47, no.3, pp.646-655, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 47 Issue: 3
  • Publication Date: 2023
  • Doi Number: 10.55730/1300-0527.3567
  • Journal Name: Turkish Journal of Chemistry
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.646-655
  • Abdullah Gül University Affiliated: Yes


TDDFT scan calculations were performed for s-carborane-anthracene derivatives $(o-CB-X-Ant where X=-H, -CH_3, -C_2H_5 and tert-butyl or -tBu)$ in order to understand the interplay between the steric effects, $S_1$ potential energy surface (PES) and photophysical properties. The results show that all systems exhibit three local minima on the S1 PES, which correspond to the emissive LE and TICT state, along with the nonemissive CT state respectively. In the case of the unsubstituted system (o-CB-H-Ant), and $CH_3 and -C_2H_5$ substituted cases, $S_1$ PES is predicted to be quite flat for certain conformations indicating that it is possible for these systems to reach the nonemissive CT state without a large energy penalty. In comparison, conformational pathways for the nonemissive CT state are predicted to be energetically unfavorable for o-CB-tBu-Ant as a result of both steric and electronic effects. These results provide a mechanism for the enhanced emission of σ-CB-fluorophore molecules with bulky ligands.