Synthesis and Determination of Acid Dissociation Constants of Bis-Acyl Thiourea Derivatives

N,N'-((dodecane-1,12-diylbis(azanediyl))bis(carbonothioyl))bis(4-nitrobenzamide) 5 and N,N'-((dodecane-1,12-diylbis(azanediyl))bis(carbonothioyl))bis(3-nitrobenzamide) 6 as bis acyl thiourea derivatives were synthesized their molecular structures characterized using 1H NMR, 13C COSY, DEPT, HMQC, FT-IR, HRMS techniques. The acid dissociation constants (pKa) of the bis-acyl 5, determined potentiometrically spectrophotometrically. pKa values products in 50% (v/v) dimethyl sulfoxide–water hydro-organic solvent presence 0.1 molL1 ionic strength NaCl acidic medium at 25±0.1 °C, two calculated for each compound with HYPERQUAD computer program data obtained from potentiometric titrations performed. In addition, three calculations HypSpec spectrophotometric performed under conditions where For compounds 6, spectrophotometrically, pKa1 was 3.56±0.08 3.87±0.01, respectively, pKa2 7.11±0.08 7.05±0.01, pKa3 12.30±0.08 11.82±0.02, respectively. It can be said that pKa1, pKa2, may belong to enol, enthiol, NH, Moreover, potentiometrically, 7.06±0.13 6.94±0.11, 12.11±0.06 11.17±0.06, it enthiol is seen spectrophotometrically are compatible other.