Substitution of thiophene oligomers with macrocyclic end caps and the colorimetric detection of Hg(II).

Alkyl substitution at the α position(s) of mono-, bi-, and terthiophenes via electrophilic addition of macrocyclic end caps combines linear, π-conjugated aromatic compounds and annular macrocycles. Addition of the Hg(II) ion to terthiophene adducts produces intense color changes, allowing for the selective, colorimetric detection of mercury(II). Chemical oxidation of the asymmetric terthiophene adduct produces the sexithiophene oligomer.