Helical twist sense bias in oligo(phenylene ethynylene)s induced by an optically active flexible tether
[graph and structure: see text] A series of tethered phenylene ethynylene oligomers, which undergo a solvent-dependent conformational transition from a random coil to a helix, has been synthesized. The use of trimethylsilyl ether protecting groups on the (+)-tartaric acid-derived tether results in the formation of helices with a large twist sense bias. In contrast, an isopropylidene ketal protecting group or no protecting group is not only ineffective at helical discrimination but may even inhibit helix formation.
Gin
MS
Department of Chemistry, The University of Illinois at Urbana-Champaign, Urbana 61801, USA.
Moore
JS