Phenyl-Substituted Cibalackrot Derivatives: Synthesis, Structure, and Solution Photophysics
JOURNAL OF ORGANIC CHEMISTRY, vol.88, no.11, pp.6573-6587, 2023 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 88 Issue: 11
- Publication Date: 2023
- Doi Number: 10.1021/acs.joc.2c02706
- Journal Name: JOURNAL OF ORGANIC CHEMISTRY
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, Chemical Abstracts Core, Chimica, Compendex, MEDLINE, Index Chemicus (IC)
- Page Numbers: pp.6573-6587
- Middle East Technical University Affiliated: No
Abstract
Three symmetrically and three unsymmetrically substitutedcibalackrot(7,14-diphenyldiindolo-[3,2,1-de:3 ',2 ',1 '-ij]-[1,5]-naphthyridine-6,13-dione, 1) dyes carryingtwo derivatized phenyl rings have been synthesized as candidates formolecular electronics and especially for singlet fission, a processof interest for solar energy conversion. Solution measurements providedsinglet and triplet excitation energies and fluorescence yields andlifetimes; conformational properties were analyzed computationally.The molecular properties are close to ideal for singlet fission. However,crystal structures, obtained by single-crystal X-ray diffraction (XRD),are rather similar to those of the polymorphs of solid 1, in which the formation of a charge-separated state followed byintersystem crossing, complemented with excimer formation, outcompetessinglet fission. Results of calculations by the approximate SIMPLEmethod suggest which ones among the solid derivatives are the bestcandidates for singlet fission, but it appears difficult to changethe crystal packing in a desirable direction. We also describe thepreparation of three specifically deuteriated versions of 1, expected to help sort out the mechanism of fast intersystem crossingin its charge-separated state.