Direct borylation of terrylene and quaterrylene

Abstract

The preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone, and all the substituents of the terrylenes and quaterrylenes were introduced before creating the rylene skeleton. In this work, we successfully synthesized 2,5,10,13-tetrakis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)terrylene (TB4) by using an iridium-catalyzed direct borylation of C–H bonds in terrylene in 56% yield. The product is soluble in common organic solvents and could be purified without column chromatography. Single crystal X-ray diffraction analysis revealed that the terrylene core is not disturbed by the substituents and is perfectly flat. The photophysical properties of TB4 are also unchanged by the substituents because the carbon atoms at 2,5,10,13-positions have less coefficients on its HOMO and LUMO, estimated by theoretical calculations. Finally, the same borylation reaction was applied for quaterrylene, resulting in the formation of soluble tetra-borylated quaterrylene despite a low yield. The post modification of rylenes enables us to prepare their borylated products as versatile units after creating the rylene skeletons.

C-H Borylation of Arenes: Steric-controlled <i>Para</i>-selectivity and Application to Molecular Nanocarbons

“…Coincidently, the iridium─ catalyzed tetraborylation of unsubstituted terrylene and quaterrylene was reported by Yamada, Aratani, and co─ workers. 41 Subsequent to our study, several para ─ and meta ─ selective C─ H borylation reactions using steric and/or coordinating effects have been reported, 14 one of which is the recent study on the meta ─ selective borylation of monosubstituted benzenes by Asako, Ilies, and co─ workers. 42 We expect that the further development of catalytic systems will realize perfect regioselectivity in a variety of aromatic systems.…”

Transition-Metal-Catalyzed Silylation and Borylation of C–H Bonds for the Synthesis and Functionalization of Complex Molecules

“…Yamada and Aratani et al have reported the borylation of terylene and quaterrylenes (Scheme ). ( n = 0 = perylene, n = 1 = terylene, n = 2 = quaterrylene)…”

“…Yamada and Aratani et al have reported the borylation of terylene and quaterrylenes (Scheme 97). 170 (n = 0 = perylene, n = 1 = terylene, n = 2 = quaterrylene) Mastalerz et al reported a route to a variety of soluble perylenes that hinges on the regioselective diborylation of a dihydroanthracene. Subsequent Suzuki−Miyaura cross-coupling and cyclization led to the desired perylenes (Scheme 98).…”

Peri‐Alkylated Terrylenes and Ternaphthalenes Building‐Blocks Towards Multi‐Edge Nanographenes**

“…Various synthetic routes were developed by Müllen and colleagues to solve the solubility and characterization issues of terrylene derivatives through introducing tertiary ‐butyl groups at the ortho ‐positions, [16–19] alkyl chains ( n ‐ethyl, n ‐hexyl) at bay ‐positions [17,20] and oxidative cyclodehydrogenation of perylene and naphthalene to yield relatively pure unsubstituted terrylene [21] (Figure 1). There were other reports on partial peri ‐methyl substituted terrylene, [22] fluoro‐terrylene, [23] benzo‐fused terrylenes, [24] ortho ‐borylation of terrylene, [25] bay ‐aryloxy substituted terrylene and azaterrylenes [26] . Comparatively, chemistry of terrylene imides was well explored due to their applications in photovoltaics, dyes, n‐type materials and organic electronics [27–34] .…”