Spectrophotometric investigation of complex formation between HMPAO and palladium(Ⅱ) ions

摘要

A system containing palladium(Ⅱ) ions and dioximc HMPAO (H_2L; L~(2-) = 4,8-diaza-3,6,6,9-tetramethylundecane-2,10-dionc dioximate ion) was investigated within a pH range of 2.0 to 7.5 (I = 0.5 mol dm~(-3)) using spcctrophotomctric measurements. Experimental data proved the formation of two different complex types: one with excessive Pd(Ⅱ) ions (λ_(max) = 370 nm) and the other with excessive HMPAO, λ_(max) = 240 nm, HMPAO to Pd(Ⅱ) ratio 1:1, and a relative stability constant log β' = 4.64 ± 0.05, at 293 K. The probable structure of the complex [Pd(HL)]~+ in solution is also suggested.