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Spectrophotometric Studies of Cobalt(II) and Copper(II) Chelates of 2‐Picolylamine
Author(s) -
Hseu TongMing,
Tsai YenHsiang
Publication year - 1974
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.197400028
Subject(s) - chemistry , chelation , cobalt , copper , ionic strength , stability constants of complexes , stoichiometry , metal , aqueous solution , inorganic chemistry , metal ions in aqueous solution , enthalpy , organic chemistry , physics , quantum mechanics
Cobalt (II) and copper (II) chelates of 2‐picolylamine have been studied spectrophotometrically in aqueous solution. Formation of 2‐picolylamine chelates was p H dependent, and the optimum p H range of the cobalt (II) chelate was at p H 8.8‐9.6, and copper(II) chelate at 4.7‐6.8, respectively. The mole ratio of 2‐picolylamine to both of metal(II) ions was found to be 2 to 1 stoichiometry. The spectrophotometric sensitivities are 0.23γ of Co/Cm 2 and 8.9γ of Cu/Cm 3 , at 373 m μ, p H 9.0 for Co(II) chelate and 588 m μ, p H 6.0 for Cu (II) chelate. The stability constants (log K ) of the chelates CoL 2 2+ and CuL 2 2+ have been evaluated at a constant ionic strength of 0.10 at 20, 25, 30, 35 and 40° C . Enthalpy and entropy changes characterizing the formation of the chelates have been calculated at 25°C The results are collected as follows: