Novel synthesis and electrochemistry of 2-(1,2-diferrocenylvinyl)-imidazoline and -imidazolidine derivatives

A new method of synthesis of 2-(1,2-diferrocenylvinyl)imidazolines 3a,b and 4a,b, 1,2-diferrocenyl-4,7-diazaspiro[2.4]hept-1-enes 5a–d and 2-(1,2-diferrocenylvinyl)-2-imidazolidinium iodides 6a–d by reactions of diferrocenyl(methylthio)cyclopropenylium iodide 1 with diamines 2a–c and piperazine 2d in the presence of Et3N (80–82 °C) is described. The structure of one of the 2-(1,2-diferrocenylvinyl)-2-imidazolidinium iodide 6c is confirmed by X-ray diffraction analysis. Electrochemical properties of the compounds 3a, 3b, 6b and 6c were investigated using cyclic square voltammetry. One adsorption process (I) and two electrochemically reversible processes II and III, associated with oxidations of the ferrocene moieties, E0′(II)E0′(II), E0′(III)E0′(III), and comproportionation constant Kcom are reported.