Synthesis and Properties of Conjugated Macrocycles Containing 2,7-Bis(2-thienyl)-9H-fluoren-9-one Units

Synthetic pathways to conjugated macrocycles containing one, two, or three 2,7-bis(2-thienyl)-9H-fluoren-9-one (TFOT) units in the macrocyclic frameworks bearing 10, 16, or 24 aromatic units were developed. The Diels–Alder reaction between (E,E)-1-(5-bromo-2-thienyl)-4-(5-iodo-2-thienyl)-1,3-butadiene and dimethyl acetylenedicarboxylate produced the key Diels–Alder adduct for the subsequent macrocyclic ring formation. UV–vis and fluorescence spectra of the TFOT-containing molecules were recorded, and their electrochemical properties were investigated by cyclic and differential pulse voltammetry. Solvatofluorochromic properties were observed for the TFOT-containing molecules.