SYNTHESIS, CHARACTERIZATION, AND CRYSTAL-STRUCTURE OF THE ISOSTRUCTURAL N,N'-(OCTANE-1,8-DIYL)BIS(GUANIDINIUM) TETRACHLOROPLATINATE(II) ANDPALLADATE(II) - ANTIAMEBIC EFFECTS STUDY

The synthesis and crystal structures of the tane-1,8-diyl)bis(guanidin ium)tetrachloroplatinate (II) or palladate (II) [C10H26N6](2+)[MCl(4)] (2-) with M = Pd(II) or Pt(II) were investigated. They are isostructur al and crystallize in the monoclinic system, space group P2(1)/c with Z = 2. For the platinum (II) compound, the cell dimensions are a = 7.5 99(2), b = 9.513(2), c = 14.200(4) Angstrom and beta = 98.57(2)degrees . The structure was refined to R = 0.025 and wR = 0.030. It consists o f square-planar [PtCl4](2-) anions and [OBG](2+) cations where [OBG](2 +) is the bis-protonated form of the organic ligand ((octane-1,8-diyl) bis(guanidine)). The cation exhibits a center of symmetry and packs in an extended ''all-trans'' configuration. The Pt(II) and Pd(II) salts were screened for their antiamebic activity against an inoculum of 10( 3) trophozoites of an Acanthameba strain implicated in an acanthamebic keratitis case. While the trophozoite inoculum was rapidly destroyed by the organic ligand, its Pt(II) salt was found exhibiting cytostatic effects. On the contrary, no effect was recorded for the Pd(II) salt. (C) 1997 Elsevier Science Inc.