The synthesis and characterization of Sn(II) and Sn(IV) complexes of nitrogen and oxygen ligands, {it p}-dimethyl aminophenylenesalicyladimine ( DPS), N,N'phenylenebis(salicylaldimine)(PBS) and N, N'-triethylenetetramine bis (salicylaldimine)(TTS) are reported. The structure of free ligands and their tin complexes were determined by elemental analysis, ir and nmr measurements. The kinetics of formation of the complexes were studied by stopped-flow technique at several temperatures with $mu$=0.100 M ($NaClO_4$). Activation parameters $DeltaH^*$ and $DeltaS^*$ were determined.