Spectrophotometric study of the pseudotetrahedral bromo-complexes of cobalt(II) in hexamethylphosphoramide solution

Abstract

Formation of the bromo-complexes of cobalt(II) in HMPA solution was investigated spectrophotometrically. It has been established that three consecutive pseudotetrahedral bromo-complexes of cobalt(II) are formed in the Co²⁺–Br^––HMPA system. The formation constants of the complexes have been calcuated: log K₁= 7.5 for ĊoBr(HMPA)₃⁺, log K₂= 4.33 for CoBr₂(HMPA)₂ and log K₃= 1.00 for CoBr₃(HMPA)^–. The coordination state of CoBr₂ in HMPA solution is reported.