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 co mplexes 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 ana lysis curves [Pt(6-MP)(2)]Cl-2. DMF indicate that DMF and HCS fragments wer e lost in a continuous manner from about 135-570 degreesC. In the case of N a(6-MP-H).H2O. decomposition steps are very well defined and show that wate r was lost between 140 and 200 degreesC. followed by the loss of an HCS fra gment between 300 and 420 degreesC. This was also the pattern of decomposit ion of the free ligand, except that the temperature range differs. These re sults clearly indicate a strong structural change of the platinum-bound 6-M P as compared to the free ligand. (C) 2001 Elsevier Science B.V. All rights reserved.