Spectrophotometric determination of the acidity dissociation constants of symmetric Schiff base derivatives

800x600 In this study, the acidity constants of series symmetric Schiff base derivatives have been determined using the UV-visible spectrophotometric method at a temperature of 25insert ignore into journalissuearticles values(±0.1); °C. The deprotonated acidity constants insert ignore into journalissuearticles values( p K a ); have been found to be associated with the deprotonation of phenolate oxygen. The first and the second protonated acidity constants insert ignore into journalissuearticles values( p K a1 and p K a2 ); have been found to cause the protonation of the imine nitrogen atom for all molecules. The deprotonated acidity constants insert ignore into journalissuearticles values( p K a ); were found for molecules 5 insert ignore into journalissuearticles values( 9.088);, 8 insert ignore into journalissuearticles values( 9.848);, 6 insert ignore into journalissuearticles values( 10.243);, 2 insert ignore into journalissuearticles values( 10.2569);, 3 insert ignore into journalissuearticles values(10.297);, 1 insert ignore into journalissuearticles values(10.587);, 7 insert ignore into journalissuearticles values( 10.692); and 4 insert ignore into journalissuearticles values(10.804);. The first protonation insert ignore into journalissuearticles values( pK a1 ); was found for molecules 2 insert ignore into journalissuearticles values( 3.432);, 5 insert ignore into journalissuearticles values( 4.207);, 8 insert ignore into journalissuearticles values( 4.612);, 7 insert ignore into journalissuearticles values( 4.758);, 4 insert ignore into journalissuearticles values(4.995);, 1 insert ignore into journalissuearticles values(5.288);, 6 insert ignore into journalissuearticles values( 5.606); and 3 insert ignore into journalissuearticles values(6.452);. The second protonation insert ignore into journalissuearticles values( pK a2 ); was found for molecules 2 insert ignore into journalissuearticles values( -5.384);, 8 insert ignore into journalissuearticles values( -5.165);, 5 insert ignore into journalissuearticles values( -5.028);, 7 insert ignore into journalissuearticles values( -4.775);, 4 insert ignore into journalissuearticles values(-4.518);, 1 insert ignore into journalissuearticles values(-4.111);, 6 insert ignore into journalissuearticles values( -3.866); and 3 insert ignore into journalissuearticles values(-3.212);. Normal 0 21 false false false TR X-NONE X-NONE MicrosoftInternetExplorer4