POSTERS

METAL IONS 8c NUCLEIC ACIDS 283

JO09 SOLUTION STUDIES AND CHARACTERISATION OF OXIDATION PRODUCTS DERIVED FROM THE DINUCLEAR+ MIXED l-METHYLTHYMIN, NH3, Cl-

;OMP;t;n [(~3)2rjt(l-MeT)ZPt(NH3!Cl] . Lippert, University of Dortmund, FRG.; A. Albinati,

Universi\y of Milano, Italy; H. Schollhorn, U. Thewalt, University of Ulm; FRG.

Models of "Platinum Pyrimidine blues" are frequently derived from dinuclear cis-diamineplatin(I1) complexes and occassionally from K2PtC14. This report will focus on a dinuclear, mixed 1-methylthymin (l-MeT), NH3, Cl-complex [(NH3)2Pt(l-MeT)2Pt(NH3)Cl][Pt(NH3)C13], 1, and its derivative [(NH3)2Pt(l-MeT)2Pt(NH3)Cl]Cl, 2. The crystal structure of 1 and of several oxidation products of 2 as well as the solution behavior of 2 wi 11 be reported.

JO10 THE EFFECT OF pH ON COMPLEXATION RATE OF AQUATED Pt(II) AMINES WITH PURINE NUCLEOSIDES. J. Arpalahti and P. Lehikoinen,

University of Turku, SF-20500 Turku, Finland. The complexation rate of aquated (dienlPt(II1 with inosine and I-

methylinosine has been studied in the pH ranqe 4.5-8.4 in aqueous solution at 298.2 K bv means of HPLC. Substituted ovridine and HNO mixtures were employed as buffers to prevent the influence of possible si *d ereactions on the complex formation studied. In both cases the complexation ability of aquated (dienlPt(II1 decreases with increasinq oH. This can be accounted for bv the deprotonation of the coordinated aqua iiqand, which vields substitution inert OH qroup. With increasinq pH the relative rate constant for inosine appears to increase sliqhtlv, which can be attributed to the deprotonation of N( 1)H of the incominq nucieoside.

J()fl INTERACTIONS OF cis-[Pt(NHs),(OH,),J2+ WITH PURINE DINUCLEOTIDES. Mark Garner, Saji S. Eapen, and

Michael Green, University of York, Heslington, York, YOl 5DD, U.K.

The steps in the reaction of cis-diamminediaqua- platinum(T1) with selected purine dinucleotides will be discussed. Enthalpies and entropies of activation for each step will be presented and anomalies discussed, together with NMR data for structural assignment of intermediates and products. The work complements and extends studies by Chottard's group [l].

[l] A. Laoui, J. Kozelka and J.-C. Chottard, Inorg. Chem. 1988, 27, 2751-2753; and ref. therein.