Synthesis, characterization and electrochemistry of diferrocenyl-1,3-thiazoles, 1,3-oxathiolanes, benzo-[b]-1,4-oxathiepines and ethyl 2-propenethioates

Abstract 2,3-Diferrocenylcyclopropenium salts react with bis-1,4-N,S- and bis-1,4-O,S-nucleophiles to yield: (1′,2′-diferrocenylvinyl)-1,3-thiazoles 6-8; (1′,2′-diferrocenylvinyl)-1,3-oxathiolanes 12a,b, 14a,b, 15b; 2,3-diferrocenyl-4H-1,4-benzo-[b]-oxathiepines 13a,b; ethyl2,3-diferrocenyl-2-propenethioates 16a,b and 2,3-diferrocenyl-3-methylthioacryl carbaldehydes Z/E-5b. New reactions for the synthesis of diferrocenyl heterocycles and diferrocenyl-2-propenethioates with several heteroatoms N,S, O and O,S, in molecules were found. The characterization of the new compounds was conducted by IR, 1H, 13C NMR spectroscopy, elemental analysis, and X-ray analysis of the compounds E-5b, 6 and 12b. The redox properties of the cycles 6, 8, 12a,b, 14a,b were investigated using cyclic (CV), differential pulse (DPV), and square wave (SWV) voltammetries. All compounds showed two reversible mono electronic oxidation processes since ΔEp(I) and ΔEp(II) are close to 0.060 V. Furthermore, the ΔE1/2 are enough separated to conclude that all the tested compounds have partially delocalized electronic charge in the mixed-valence state, according to the Robin-Day classification.