New Functional Hexahelicenes − Synthesis, Chiroptical Properties, X‐ray Crystal Structures, and Comparative Data Bank Analysis of Hexahelicenes

Abstract

Abstract Seven new hexahelicenes ( 3−7 , 9 , 10 ) containing different functional group substituents have been synthesized and, in three cases ( 4 , 8 , 10 ), optically resolved. Optical rotations were measured and CD spectra are reported. X‐ray crystal structures of the helicenes 1 , 3 , 4 , 8 , and 9 have been determined, of which 4 represents a 1:1 clathrate with acetone. These show a concerted interplay of C−H ··· O, C−H ··· π, and π ··· π supramolecular interactions in the packings, mostly yielding stacks of molecules ( 1 , 3 , 4 , 8 ). Statistical analysis of the molecular dimensions in these and related crystal structures was carried out in order to identify potential parameters relevant to macroscopic phenomena, including optical rotation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)