Study of the reaction of complexation of penicillin V with cobalt(II) in methanolic medium.

Abstract As shown by spectrophotometry, two specific complexes with stoichiometry 1:1 and 2:1 are formed when penicillin V reacts with cobalt(II) in a methanolic medium. Stability constants are determined at 20°, as well as the molar absorptivities at 510 nm. The results obtained are: log β 1:1 = 1.67 ± 0.01 l·mole −1 and log β 2:1 = 5.76 ± 1.01 l 2 ·mole −2 , ϵ 1:1 = 13.62 ± 0.73 and ϵ 2:1 = 12.95 ± 0.61 l·mole −1 ·cm −1 .