Synthesis and Photophysical Properties of Soluble N‐Doped Rubicenes via Ruthenium‐Catalyzed Transfer Hydrogenative Benzannulation

Abstract

Ruthenium‐catalyzed butadiene‐mediated benzannulation enabled the first synthesis of 3,10‐(di‐tert‐butyl)rubicene and its N‐doped derivatives as well as preliminary studies on their photophysical properties. Unlike the parent rubicene and 3,10‐(di‐tert‐butyl)rubicene, which adopt classical herringbone‐type packing motifs in the solid state, the N‐doped congener 7 b displayed columnar packing with an alternating co‐facial arrangement of aromatic and heteroaromatic substructures.

Chemical Tuning of Exciton versus Charge-Transfer Excited States in Conformationally Restricted Arylene Cages

“…Using a ruthenium-catalyzed dioldiene [4 + 2] cycloaddition, 37 a protocol for benzannulation was developed in the laboratory of one of the present authors. 38 This method opened novel synthetic routes to diverse polycyclic aromatic hydrocarbons: acenes and fluoranthenes, 38 oligo(o,p-phenylenes) and, therefrom, nanographenes, 39 diindenoperylenes (periflanthenes), 40 rubicenes, 41 and a novel class of triple helical phenylene cages, 42 including an all-aryl caged fac-Ir(ppy) 3 analog. 43 The relatively rigid topology of the arylene cages and the roughly orthogonal orientation of their walls vs caps inspired the design of the cages 4a (Z = CH) and 4b (Z = N), which have 5,5-(2,2bithiophene) walls terminated by 1,3,5-benzene or s-triazine caps, respectively.…”

Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

“…In 2021, Krische et al reported a two-step synthesis of the π-extended diazarubicenes 261.3a – c ( Scheme 261 ). 491 Quinoxalines 261.2a – c were initially obtained by selective condensation of one diketone moiety of 261.1 with an appropriate ortho -phenylenediamine (the formation of the tetrafluoro congener 261.2c required the presence of Sc(OTf) 3 ). Compounds 261.2a – c were then subjected to ruthenium-catalyzed transfer hydrogenative benzannulation with 1,3-butadiene to yield the target 261.3a – c .…”

Recent progress in pyrazinacenes containing nonbenzenoid rings: synthesis, properties and applications

“…Very recently, the Krische group 25 synthesized a class of highly soluble N-doped rubicenes through their previously reported strategy of ruthenium-catalyzed butadiene-mediated benzannulation. Initially, chemoselective condensation of the critical tetraketone 52 with various 1,2-diamines enabled mono-condensation products 53a–d in good yields (Scheme 9a).…”

“…23 Similarly, the newly developed strategy of ruthenium-catalyzed butadiene-mediated benzannulation allows a quick synthesis of azaacenes bearing a five-membered ring with high yields. 25 We also include several interesting azaacenes bridged by macrocycles (≥7-membered ring) and highlight their size-dependent properties. It is worth pointing out that some selected molecules in this review may not be as ordered as those formally well-defined (aza)acenes 26–37 due to the diverse scaffolds and irregular shapes of the embedded units.…”