FERROCENE CONTAINING CHELATING LIGANDS .2. SYNTHESIS, CHARACTERIZATION, ELECTROCHEMICAL-BEHAVIOR AND CRYSTAL-STRUCTURE OF 2-FERROCENYLMMTHYLAMINO-BENZOIC ACID

Ferrocenecarboxaldehyde reacts with 2-amino-benzoic acid in benzene to give the Schiff base derivative 2-ferrocenylmethylidenimino-benzoic acid (eta5-C5H5)Fe[(eta5-C5H4)-CH= N-C6H4-COOH] (1). 1 is stable as a solid but easily hydrolyzes in solution. Selective hydrogenation of the imine group can be performed using NaBH4 to obtain the parent amine (eta5-C5H4)Fe[eta5-C5H4)-CH2-NH-C6H4-COOH]. (2). The molecular structure of 2 has been determined by single-crystal X-ray methods. It crystallizes in the space group P2(1)/c, a=11.077(9), b=7.430(2), c=19.194(9) angstrom, beta=111.02(4)-degrees, V=1474(2) angstrom3, Z=4. Refinement of the structure gave final R factor of 0.038 (R(w)=0.035) for 1106 unique reflections having F(o)2 > 2.8sigma(F(o)2). 2 is stable both in the solid state and solution, and a potential chelating N,O-donor ligand containing a ferrocenyl group. A one-electron oxidation process was found by cyclic voltammetry (0.1 M NBun4PF6, CH2Cl2) for 1 and 2 at 0.74 and 0.51 V, respectively.