A heterotrinuclear and a polynuclear complex constructed from a ferrocenyl carboxylate and an N-containing ligand: Synthesis, crystal structures and electrochemical properties

Treatment of NaO2CCHdouble bond; length as m-dashC(Me)Fc with cadmium acetate and iron(II) sulfate in the presence of 2,2′-bipy yielded [Cd2Fe(μ-O2CCHdouble bond; length as m-dashC(Me)Fc)2(μ2-O2CCHdouble bond; length as m-dashC(Me)Fc)2(μ2-η2-O2CCHdouble bond; length as m-dashC(Me)Fc)2(2,2′-bipy)2] · 2H2O (1); while from NaO2CC6H4{C(O)Fc-o}, cadmium acetate, and pbbm the product was {[Cd(η2-O2CC6H4{C(O)Fc-o})2(pbbm)] · 0.5H2O}n (2) [Fc = (η5-C5H5)Fe(C5H4-η5); 2,2′-bipy = 2,2′-bipyridyl; pbbm = 1,1′-(1,5-pentamethylene)bis-1H-benzimidazole]. Compounds 1 and 2 have been characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. In centro-symmetric crystalline 1, the Fe and the two flanking atoms are six-coordinate; the three carboxylato ligands between the Fe and a Cd atom have different coordination modes. Crystalline 2 consists of an infinite polymeric chain, in which adjacent [Cd(η2-O2CC6H4{C(O)Fc-o})2] units are linked by pbbm ligands; thus each Cd atom is six-coordinate. Some electrochemical properties of the two complexes are reported.