KINETIC-STUDY OF THE STABILITY OF (NH2)(2)CSSC(NH2)(2)(2+)

The kinetics of the decomposition of formamidine disulfide dihydrochlo ride, (NH2)(2)CSSC(NH2)2(2+) 2Cl(-), in aqueous solution at 25 degrees C are general base catalysed, and rate constants have been measured o ver the pH range 1.91-9.03. Analysis of the data yields ionisation con stants pK(1) = 5.49, pK(2) = 7.66 and rate constants for deprotonation of the substrate by OH- and H2O. For the doubly charged cation, react ion occurs through a small concentration of a reactive tautomer, (HN=) (NH3+)CSSC+(NH2)(2), which is attacked by H2O. The singly charged cati on reacts by parallel pathways involving OH- and H2O as attacking base s.