Functionalized Hydrocarbon Belts: Synthesis, Structure and Properties

Angew Chem Int Ed Engl. 2023 Jun 12;62(24):e202302646. doi: 10.1002/anie.202302646. Epub 2023 May 8.

Abstract

Hydrocarbon belts have drawn great attention because of their unique structures and tantalizing properties. Although a few belts and heteroatom-doped analogs have been synthesized, belt molecules containing non-hexagonal rings remain rare. Herein we report the construction and application of unprecedented zigzag-type hydrocarbon belts which contain functionalized eight-membered rings. The synthesis features fourfold intramolecular acylation reactions of resorcin[4]arene-derived intermediates, which affords C4 -symmetric tetrabenzobelt[4]arene[4]cyclooctatrienones. Stereoselective ketone reduction with LiAlH4 and nucleophilic addition with alkynyllithiums provide the corresponding tetrahydroxylated belts. The tetraol and its methyl ether are powerful and selective hosts to form 2 : 1 and 1 : 1 complexes with cesium ion, respectively, with binding constants up to (1.71±0.33)×1011 M-2 and (1.50±0.16)×106 M-1 . In addition, enantiopure C4 -symmetric belts can emit CPL with |glum | being around 0.01.

Keywords: Cesium; Circularly Polarized Luminescence; Hydrocarbon Belt; Resorcin[4]Arene; Zigzag.