Redox-Active Multi-Thianthrene Cycloparaphenylenes: Synthesis and Supramolecular Properties

Abstract

Thianthrene is widely used building-block for developing p-type organic semiconductors. The rich electrochemistry of thianthrene enables a switch between its characteristic nonplanar and planar forms, and its incorporation into macrocyclc systems can provide increased solubility and improved host-guest complexation. Cycloparaphenylenes (CPPs) are a relatively new class of nonplanar aromatic macrocycles whose stewise synthesis enables precise control over their properties. In this work, we report high-yielding transformations of fluorinated CPPs into multi-thianthrene-containing strained macrocyclic nanocarbons. Single crystal X-ray diffraction of dodeca-substituted CPP (2) reveals tub-shaped 5,7,12,14-tetrathiapentacene (TTP) units that curve around neighboring CPPs to form hexagonal crystals. Host-guest complexation with C60 shows increased binding constants upon TTP inclusion, and cyclic voltammetry reveals that TTP incorporation lowers oxidation potentials of the CPPs compared to all hydrocarbon counterparts. This efficient strategy for introducing functional heterocycles into CPPs expands the toolkit for designing strained, pi-rich, redox-active macrocycles with tunable supramolecular properties.