METALS IN MEDICINE 223

C40 MONOMERIC Pt(ll) AND DIMERIC Pt-Pt AND Pt-Pd COMPLEXES OF A TRIAZOLO PYRIMIDINE DERIVATIVE

J. Rodrfguez a, J.M. Salas% M.A. Romero a, M. Quir6s ~ and R. Faure b. Departamento de Qu[mica Inorgdnica, Facultad de Ciencias,

Universidad de Granada. 18071 Granada, Spain. b Laboratoire de Chimie Analytique II, Universit# Claude Bernard. Lyon I, 69622 Villeurbanne Cedex, France.

The ligand 5-methyl-[1,2,4]tr iazolo-[1,5-a]pyrimidine-7-ol (mtpOH) reacts wi th K2[PtCI 4] in 0.5 M hydrochloric acid yielding cis-[PtCI2(mtpOH)2].H20 (I). Dissolving this compound in a NaOH solution causes its decomposition and, from this solution, the dimeric complex [Pt2(mtpO)4].4H20 (11) crystallizes out.

On the other hand, the reaction at 45°C of cis-[Pt(NH3)2 (H20)2](NO3) 2 wi th mtpOH in aqueous solution leads to the formation of cis-[Pt(NH3)2(mtpO)2](NO3)2"2H20 (111). This compound reacts wi th [PdA(H20)2] 2+ (in which A =ethylenediammine, propilenediammine, bipyridine and 1.10-phenantroline) in basic media to form heterome- tallic Pt-Pd complexes with formulae cis-[Pt(NH3)2(mtpO)2PdA].

The structure of cis-[Pt(NH3)2(mtpO)2Pd(bipy)]'H20 (IV), as well as those of I, II and Iii has been solved by single crystal X-r,w diffraction. In the monomeric platinum complexes I and III, the ligand binds monodentately through N3, whereas in the dimeric complexes, it bridges the two metal centres through N3 and N4 (in the Pt-Pd compound, N3 to Pt and N4 to Pd, see Figure 1).

Pd

Figure 1: Molecular structure of compound IV.