Speciation of organotin compounds in NaCl aqueous solution. Interaction of mono-, di- and triorganotin(IV) cations with nucleotides 5’ monophosphates

Formation constants for complex species of mono-, di- and tri-alkyltin(IV) cations with somenucleotide 5-monophosphates (AMP, UMP, IMP and GMP) are reported, atT=25◦CandatI=0.16 mol l−1(NaCl). The investigation was performed in the light of speciation of organometalliccompounds in natural fluids in the presence of nucleotides whose biological importance is wellrecognized. The simple and mixed hydrolytic complex species formed in all the systems investigatedin the pH range 3–9 are (L=nucleotide; M=organotin cation RxSn(4−x)+, withx=1to3):ML+,ML(OH)0and ML(OH)2−for the system CH3Sn3+–L (L=AMP, IMP, UMP); ML0and ML(OH)−for the system (C2H5)2Sn2+–L (L=AMP, IMP, UMP); ML−, ML(OH)2−,MLH0and M2L(OH)−forthe system (C2H5)3Sn+–L (L=AMP); ML, ML(OH)2−and M2L0for the system (C2H5)3Sn+–L (L=IMP, UMP). As expected, owing to the strong tendency of organotin(IV) cations to hydrolysis inaqueous solution, the main species formed in the pH range of interest of natural fluids are the mixedhydrolytic ones.