Abstract

The synthesis of neutral dinuclear unsymmetrical Schiff base complexes 1 and 2 was carried out in an one-pot two-step reaction sequence that involves the reaction of 1-ferrocenyl-1,3-butanedione with an excess of ethylenediamine in refluxing CH2Cl2, to generate the intermediate "half-unit" Fc-C(O)CH2C(CH3)=NCH 2CH2NH2, Fc = (η5-Cp) Fe(η5-C5H4), Cp = C5H 5), followed by its in situ templated reaction with salicylaldehyde and nickel(II) or copper(II) acetate in refluxing CH2Cl 2-EtOH (3: 1) mixture. On the other hand, ionic trinuclear unsymmetrical complexes [3]+PF6 - and [4] +PF6 - were synthesized by reacting dinuclear precursors 1 and 2, respectively, with [(η5-Cp*)Ru(CH 3CN)3]+PF6 -, Cp* = C5Me5, in refluxing CH2Cl2. Both complexes contain the neutral electron-releasing ferrocenyl group and the cationic electron-withdrawal sandwich, [(η5-Cp*) Ru(η6-arene)]+, connected by a tetradentate {M(ONNO)} chelate (M = Ni, Cu). The new unsymmetrical organometallic Schiff base compounds were characterized by elemental analysis, IR, UV-Vis, 1H NMR and EPR spectroscopy. In addition, the Ni(II) containing complexes 1 and [3] +PF6 - were authenticated by X-ray diffraction analysis. Solvatochromic and electrochemical properties were also studied. The organometallic-inorganic hybrid unsymmetrical Schiff base complexes [3] +PF6 - and [4]+PF6 - can be defined as type I non-rod-shaped dipolar chromophores. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.