Synthesis, structure and tropicity of an [11][13]fulvalene derivative

Abstract

An [11][13]fulvalene derivative, 13-(4,9-methanocycloundeca-2,4,6,8,10-pentaenylidene)-4,9-dimethylcyclotrideca-1,3,9,11-tetraene-5,7-diyne, has been synthesized. Examination of ¹H and ¹³C NMR spectra indicates that the compound shows no detectable ring-current effect in nonpolar solvents arising from 10π- and 14π-electron systems, which is verified by X-ray crystallographic structural analysis. In a polar solvent, [²H₆]dimethyl sulfoxide, a small contribution of the dipolar resonance structure is suggested.