PT-195 AND H-1-NMR STUDY OF THE PRODUCTS OF HYDROLYSIS OF PT(L)X2, WHERE L IS AN ETHYLENEDIAMINE DERIVATIVE, AND THE CRYSTAL-STRUCTURE OF [PT(N,N-DIMETHYLETHYLENEDIAMINE) (MU-OH)]2(NO3)2

The hydrolysis reactions of complexes of the type Pt(L)X, where L is ethylenediamine (en), N,N-dimethylethylenediamine (NN-Me2en), N,N'-dimethylethylenediamine (N,N'-Me2en) and N,N,N',N'-tetramethylethylenediamine (Me4en) were studied. The halo ligands were removed by precipitation with AgNO3 and the pH of the resulting filtrate, which was about 2, was adjusted to 5.8 (pD = 6.2). The study of the products formed was carried out by multinuclear NMR spectroscopy. The Pt-195 NMR spectra showed the presence of several hydrolysed products, especially with en. The hydroxo-bridged dimer can be synthesized in a pure state with all the ligands except en. The results on the latter ligand contradict the published results on the synthesis of the en hydroxo-bridged dimer whose biological properties were studied. When Pt(L)I2 is used as starting material a small quantity of chloro species was always observed, indicating that the reactant contained a small quantity of Pt(L)ICl. The crystal structure of the [Pt(N,N-Me2en)(mu-OH)]2(NO3)2 dimer was determined. The compound belongs to the P2(1)/c space group, with a = 8.262(5), b = 10.960(8), c = 11.405(8), beta = 121.07(5)-degrees, Z = 2 and rho(calc) = 2.720 mg m-3. The results showed that this is the trans isomer with an inversion centre between the two Pt atoms. There is a considerable strain inside the four-membered ring, as shown by the reduced internal angles O-Pt-O' = 79.1(6)-degrees and Pt-O-Pt' = 101.0(6)-degrees.