Get access

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


  • This work was supported by Grant-in-Aids for Scientific Research (B) (No. 16350073) and Exploratory Research (18655016) from the Ministry of Education, Culture, Sports, Science and Technology (Japan).


original image

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.

Get access to the full text of this article