TEtraQuinolines: A Missing Link in the Family of Porphyrinoid Macrocycles

Wei Xu, Yuuya Nagata, Naoya Kumagai

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


Porphyrin contains four inwardly oriented nitrogen atoms. It is arguably the most ubiquitous multifunctional naturally occurring macrocycle that has inspired the design of novel nitrogen-containing heterocycles for decades. While cyclic tetramers of pyrrole, indole, and pyridine have been exploited as macrocycles in this category, quinoline has been largely neglected as a synthon. Herein, we report the synthesis of TEtraQuinoline (TEQ) as a ‘missing link’ in this N4 macrocycle family. In TEQs, four quinoline units are concatenated to produce an S4-symmetric architecture. TEQs are characterized by a highly rigid saddle shape, wherein the lone-pair orbitals of the four nitrogen atoms are not aligned in a planar fashion. Nevertheless, TEQs can coordinate a series of transition-metal cations (Fe2+, Co2+, Ni2+, Cu2+, Zn2+, and Pd2+). TEQs are inherently fluorescence-silent but become strongly emissive upon protonation or complexation of Zn(II) cations (ϕ = 0.71). TEQ/Fe(II) complexes can catalyze dehydrogenation and oxygenation reactions with catalyst loadings as low as 0.1 mol %.

Original languageEnglish
Pages (from-to)2609-2618
Number of pages10
JournalJournal of the American Chemical Society
Issue number4
Publication statusPublished - 2023 Feb 1

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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