Self-assembled, helically stacked anionic aggregates of 2,5,8,11-tetra-tert-butylcycloocta[1,2,3,4-def; 5,6,7,8-d′e′f′] bisbiphenylene, stabilized by electrostatic interactions

Roy Shenhar, Hua Wang, Roy E. Hoffman, Limor Frish, Liat Avram, Itamar Willner, Andrzej Rajca, Mordecai Rabinovitz

Research output: Contribution to journalArticle

20 Scopus citations


Tetraanions of alkyl-substituted derivatives of cycloocta[1,2,3,4-def, 5,6,7,8-d′e′f′]bisbiphenylene (BPD) and their counter lithium cations self-assemble to form helically stacked assemblies, including a dimer, a trimer, and a tetramer. NMR self-diffusion measurements and unprecedented magnetic shielding effects for the sandwiched lithium cations support their aggregated nature. The D2-tetramer assembly is fully characterized by NMR spectroscopy, providing unequivocal evidence for a helix of four tetraanionic BPD layers with an estimated relative twist angle of about 45° and interlayer spacing of ca. 4 Å. The barrier for racemization through the in-plane inter-deck rotation is ΔG200 = 9.5 ± 0.2 kcal mol-1 in the dimer compared to > 15 kcal mol-1in the tetramer.

Original languageEnglish (US)
Pages (from-to)4685-4692
Number of pages8
JournalJournal of the American Chemical Society
Issue number17
StatePublished - May 1 2002


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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