1-vinylazulenes – potential host molecules in ligands for metal ion detectors

Abstract

Several vinylazulenes containing metalophilic groups were prepared as potential host molecules in ligands for metal ion detectors. The azulene-1-carbaldehyde derivatives were condensed with methylene active compounds in the presence of piperidine. The reaction is influenced by both the nature of the methylene activating groups and by the presence of the alkyl groups on the 4-,6- or 8- position of the azulene moiety. Some unusual reagents, as nitroacetate were condensed with imines activated by acetic anhydride. Several autocondensation azulenic products were evidenced in the presence of weak activated methylenes. Considerations regarding S1 and S2 absorption bands of the azulene compounds were revealed and correlated with frontier molecular orbitals. At the same time, the prepared ligands redox potentials were investigated by differential pulse voltammetry (DPV).