Reactions of N,N '-dicarboxamido-N,N '-dicarboxymethyl-1,2-diaminoethane (EDTA-diamide) with hydrated ruthenium(III) chloride and potassium tetrachloroplatinate(II). Crystal and molecular structures of the pentadentate EDTA-H complex NH4[Ru(EDTA-H)Cl]center dot 2H(2)O and the EDTA-imide complex PtCl2[(2)(HOOCCH2)NCH2CH2NCH2CONHCOCH2]center dot 2H(2)O

Treatment of ruthenium (III) chloride hydrate with N,N'-dicarboxamido-N,N'- dicarboxymelhyl-1,2-diaminbethane (1) (EDTA-diamide) in refluxing HCl solut ion followed by cooling afforded the crystalline complex NH4[Ru(EDTA-H)Cl]. 2H(2)O (2), the EDTA-H ligand and the +NH4 cation resulting from the hydro lysis of the amide groups in 1. The crystal and molecular structure confirm s that in this complex EDTA-H acts as a pentadentate ligand, bonded to the metal through the tertiary nitrogen atoms and three carboxylate oxygens. A chloride ligand completes octahedral geometry around the metal ion. Reactio n of K-2[PtCl4] with the same ligand in hot basic solution followed by acid ification initially gave PtCl2[HOOCCH2(2HNOCCH2)NCH2CH3 NCHCONHCOCH2]. H2O (3) which on standing gave PtCl2[(2)(HOOCCH2)NCH2CH2NCH2CONHCOCH2]. 2H(2)O (4), the crystal structure of which is also reported. This is a square plan ar complex of platinum(II) formed as a result of an acid-amide ring closure of ligand 1 and subsequent hydrolysis of the second amide group. The react ion of K-2[PtBr4] with 1 under similar conditions gave the complex PtBr2[HO OCCH2(2HNOCCH2)NCH2CH2NCH2CONHCOCH2]. H2O (5), The reaction of 1 with K-2[P tCl4] in neutral solution at 30 degrees C gave PtCl[OOCCH2(2HNOCCH2)NCH2CH2 N(CH2CONH2)CH2COOH] (6) which was converted to PtCl2[HOOCCH2(2HNOCCH2)NCH2C H2N(CH2CONH2)CH2COOH] (7) on treatment with HCl solution. The IC50 value of complex 7 against murine P388 leukemia cells is 157 +/- 37 mu M compared t o its value of 2.05 mu M for cisplatin. (C) 1998 Elsevier Science Ltd. All rights reserved.