IONIC TITANOCENE(IV) ALPHA-AMINO-ACID COMPLEXES OF DL-PHENYLALANINE AND DL-4-FLUOROPHENYLALANINE - SYNTHESIS, CHARACTERIZATION, AND INVESTIGATION OF THE ANTIMICROBIAL BEHAVIOR TOWARD ESCHERICHIA-COLI

Antitumor-active titanocene dichloride (Cp(2)TiCl(2); Cp = eta(5)-C5H5 ) reacts with alpha-amino acids (aa) in methanol to give the titanium( IV) amino acid complexes [Cp(2)Ti(aa)(2)](2+)[Cl](-)(2) (aa = DL-pheny lalanine, 1; DL-4-fluorophenylalanine, 2). Metathetical reactions of 1 and 2 with 2 equiv of AgAsF6 yielded the ionic complexes [Cp(2)Ti(DL- Phe)(2)](2+)[AsF6](2-) (3) and [Cp(2)Ti(DL-4-F-Phe)(2)](2+)[AsF6](-)(2 ) (4). All complexes have been characterized by chemical analyses (C/H /N) and NMR (H-1, N-14, F-19), infrared, and Raman spectroscopy. Preli minary structural data of complex 4 are also presented: monoclinic, P2 1/c; a = 11.751(3), b = 20.257(3), c = 16.080(4) Angstrom; beta = 110. 01(0)degrees; Z = 4. In addition, the antimicrobial behavior (against E. coli) of all complexes was determined and is discussed in compariso n with the free amino acids. It was established that not only DL-4-flu orophenylalanine but also the titanocene complex 2 and, to some minor extent, also 3 and 4 cause elongation of E. coli.