Synthesis, Fourier transform infrared, nuclear magnetic resonance and thermal analysis of sodium and platinum complexes of 6-mercaptopurine

The preparation of the complexes Na(6-MP-H).H2O and [Pt(6-MP)(2)]Cl-2. DMF (6-MP = 6-mercaptopuine: DMF = N,N-dimethylformamide) are reported. Both complexes were prepared in alkaline medium. Nuclear magnetic resonance (NMR) spectra show that Na is bound to N-9 of ionized 6-mercaptopurine whereas Pt(II) is coordinated to the neutral ligand through N? and S. The thermal analysis curves [Pt(6-MP)(2)]Cl-2. DMF indicate that DMF and HCS fragments were lost in a continuous manner from about 135-570 degreesC. In the case of Na(6-MP-H).H2O. decomposition steps are very well defined and show that water was lost between 140 and 200 degreesC. followed by the loss of an HCS fragment between 300 and 420 degreesC. This was also the pattern of decomposition of the free ligand, except that the temperature range differs. These results clearly indicate a strong structural change of the platinum-bound 6-MP as compared to the free ligand. (C) 2001 Elsevier Science B.V. All rights reserved.