Cyclic [5]Paraphenyleneacetylene: Synthesis, Properties, and Formation of a Ring‐in‐Ring Complex Showing a Considerably Large Association Constant and Entropy Effect

Abstract

In the ring: The title compound ([5]CPPA), the smallest belt-shaped conjugated system known to date, forms a considerably stable ring-in-ring complex with [8]CPPA (see picture). [8]CPPA⊃[5]CPPA has a smaller contact area than [9]CPPA⊃[6]CPPA but its large Ka and ΔH values reveal that the interaction results from the electrostatic attractive force rather than the dispersion force. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z603707_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.