SPECTROPHOTOMETRIC STUDIES OF SOME BIS-AZO-BETA-DIKETONE COMPOUNDS AND THEIR IONIZATION-CONSTANTS IN MIXED BUFFER SOLUTIONS

A series of bis-azo compounds have been prepared from m- and p-phenyle nediamine and beta-diketones. The electronic absorption spectra of the compounds have been studied in organic solvents of different polariti es. The effect of medium on band position and band assignment has been considered. The ir and H-1 nmr spectra are discussed in relation to m olecular structure. The spectral changes in buffer solution of pH cong ruent-to 2-12 were used for calculating the pK(a) values of the bis-az o compounds under study.