Speciation of organotin compounds in NaCl aqueous solution:interaction of mono-,di-and tri-organotin(IV)cations with nucleotide 5' inonophosphates

摘要

Formation constants for complex species of mono-,di-and tri-alkyltin(IV)cations with some nucleotide 5'-monophosphates(AMP,UMP,IMP and GMP)are reported,at r=25 degC and at I=0.16 mol l~(-1)(NaCl).The investigation was performed in the light of speciation of organometallic compounds in natural fluids in the presence of nucleotides whose biological importance is well recognized.The simple and mixed hydrolytic complex species formed in all the systems investigated in the pH range 3-9 are(L=nucleotide;M=organotin cation R_x Sn~(4-x)+,with x=1 to 3):ML~+,ML(OH)° and ML(OH)_2~-for the system CH_3Sn~3+-L(L=AMP,IMP,UMP);ML~0 and ML(OH)~-for the system(C_2H)_5)_2Sn~(2+)-L(L=AMP,IMP,UMP);ML~,ML(OH)~2-,MLH° and M2L(OH)~ for the system(C_2H_5)_3Sn+-L(L=AMP);ML,ML(OH)~2-and M_2L~0 for the system(C_2H_5)_3Sn~+-L(L=IMP,UMP).As expected,owing to the strong tendency of organotin(IV)cations to hydrolysis in aqueous solution,the main species formed in the pH range of interest of natural fluids are the mixed hydrolytic ones.