In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarog...In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarographic experimental complex formation curve (ECFC) and the theoretical complex formation curve (TCFC) were used for modelling the metal ligand system and optimizing stability constants. The ECFC, in which experimental parameters of polarography are included (a shift in a half wave potential and a variation in a diffusion controlled limiting current), appears to be a characteristic function for a particular metal ligand system. The TCFC is a theoretical curve calculated for the designed metal ligand model from mass balance equation. Five bismuth complexes MHL, ML, ML2, ML3 and ML3(OH) with their stability constants as logβ 7.54± 0.10, 7.50± 0.02, 13.91± 0.04, 18.15± 0.03 and 26.75± 0.02, respectively, are reported.展开更多
文摘In this paper the Bi? ligand(pyridine 2 carboxylic acid) system was studied by direct current sampled polarography (DC _ TAST) at a fixed ratio of total ligand to total metal concentration and changing pH. The polarographic experimental complex formation curve (ECFC) and the theoretical complex formation curve (TCFC) were used for modelling the metal ligand system and optimizing stability constants. The ECFC, in which experimental parameters of polarography are included (a shift in a half wave potential and a variation in a diffusion controlled limiting current), appears to be a characteristic function for a particular metal ligand system. The TCFC is a theoretical curve calculated for the designed metal ligand model from mass balance equation. Five bismuth complexes MHL, ML, ML2, ML3 and ML3(OH) with their stability constants as logβ 7.54± 0.10, 7.50± 0.02, 13.91± 0.04, 18.15± 0.03 and 26.75± 0.02, respectively, are reported.
