Report No xxxx - Instytut Fizyki JÄ drowej PAN

1 H NMR STUDIES OF PLATINUM(II) CHLORIDE COMPLEXES
REACTION WITH GUANOSINE-5’-MONOPHOSPHATE
Iwona Łakomska 1 , Edward Szłyk 1 , Leszek Pazderski, 1 Jan Reedijk 2
1 Faculty of Chemisty, Nicolas Copernicus University, 87-100 Toruń, Poland, email:
dziubek@umk.pl; 2 Gorlaeus Laboratories, Leiden University of Chemistry, P.O. Box 9502,
2300 RA Leiden, The Netherlands
Studies on the binding of cis-[PtCl 2 (dmtp)(NH) 3 ] and cis-[PtCl 2 (tmtp)(NH) 3 ] to model
nucleotide guanosine- 5’-monophosphate (5’-GMP) are important for the explanation of the
molecular interaction between antitumor platinum complex and DNA. The Pt binding
to 5’-GMP has been studied by 1 H NMR, using a fourfold excess of guanosino-5’-
monophoshate. The Pt-GMP interaction can be followed, by observing the formation and
disappearance of several platinum-GMP species. The chemical shift of the H(8) proton of
GMP is very sensitive to the geometry and the composition of the complex.
The reactions of cis-[PtCl 2 (dmtp)(NH) 3 ], cis-[PtCl 2 (tmtp)(NH) 3 ] were very slow for
NMR time scale, and therefore we decided to study the reaction between monoaquaspieces:
[PtCl(D 2 O)(dmtp)(NH 3 )] + , [PtCl(D 2 O)(tmtp)(NH 3 )] + . In all cases, the typical downfield shift
of H8 of 5’-GMP (8.19 ppm for H(8) of free 5’-GMP; 8.5 ppm for H(8) of bis-bound and 8.8-
8.7 ppm for H(8) of mono-bound 5’-GMP) was observed, indicating that the platination site
of in N(7) position 5’-GMP for all complexes. For the 1:1 adduct of platinum(II) complexes
two H(8) resonance peaks would be expected in 1 H NMR spectra, as the 5’-GMP in each
intermediate has a slightly different chemical magnetic environment.
Acknowledgements
Financial support from Polish Committee for Scientific Research (KBN) the grant No:
4 T09A 11623 is gratefully acknowledgment.
51