Multinuclear 1D and 2D NMR investigations on the interaction between the pyrimidic nucleotides 5 '-CMP, 5 '-dCMP, and 5 '-UMP and diethyltin dichloride in aqueous medium

The interactions between diethyltin dichloride and 5'-CMP, 5'-dCMP, and 5'- UMP in aqueous solution were investigated by multinuclear 1D and 2D NMR tec hniques including Sn-119, N-15 and P-31 nuclei. These studies were combined with electrospray mass spectrometry, infrared spectroscopy, solid state C- 13, P-31 and Sn-117 CP-MAS NMRI and elemental analysis. As demonstrated by P-31-H-1 HOESY spectroscopy the diethyltin moiety interacts with the phosph ate group of the pyrimidic mononucleotides in the pH range 0.5-3.5. Compoun d 8 (X = Cl), the solid isolated in this pH range from 5'-CMP, contains two tin atoms bridged by one oxygen and one chlorine atom, each tin atom being linked to the phosphate group of a nucleotide moiety. For 5'-UMP the solid isolated (12) has a dimeric structure with two different tin atoms; it can be formed by dimerization of compound it with the elimination of two water molecules. As demonstrated by H-1-Sn-119 HMQC correlation NMR data and the (2)J(Sn-119-O-Sn-117) coupling constant of 156 Hz, the diethyltin moiety r eacts with the O(2') and O(3') oxygen atoms of the nucleotides to form a di meric diethyldioxastannolane at pH > 9.0. Between pH 5.0 and 9.0, no eviden ce for any interaction between the diethyltin moiety and the nucleotides wa s found.