Control of metal ion selectivity in ligands containing neutral oxygen and pyridyl groups

Journal Article · Wed Oct 22 04:00:00 EDT 1986 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00242a010· OSTI ID:6996758

Damu, K V; Shaikjee, M S; Michael, J P; Howard, A S; Hancock, R D

The stabilities of the complexes of the ligand (py)/sub 2/-18-aneN/sub 2/O/sub 4/ (N,N'-bis(o-pyridylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) at 25/sup 0/C in 0.1 M NaNO/sub 3/ are reported, as well as those of DHEAMP (((bis(2-hydroxyethyl)amino)methyl)-pyridine, with a variety of metal ions. The log K/sub 1/ values for the (py)/sub 2/-18-aneN/sub 2/O/sub 4/ complexes are as follows: Cu/sup 2 +/, 13.55; Ni/sup 2 +/, 8.80; Zn/sup 2 +/, 6.96; Cd/sup 2 +/, 10.96; Ca/sup 2 +/, 3.63; La/sup 3 +/, 3.53; Sr/sup 2 +/, 4.87; Pb/sup 2 +/, 11.67; Ba/sup 2 +/, 4.99. The constants for the protonation equilibria were, for H/sup +/ + L = HL/sup +/, log K = 7.44, for H/sup +/ + HL/sup +/ = H/sub 2/L/sup 2 +/, log K = 6.26, and for H/sup +/ + H/sub 2/L/sup 2 +/ = H/sub 3/L/sup 3 +/, log K = 1.38. For DHEAMP, log K values are as follows: Cu/sup 2 +/, 9.2; Ni/sup 2 +/, 7.34; Zn/sup 2 +/, 5.25; Ca/sup 2 +/, 1.0; La/sup 3 +/, 1.95; Pb/sup 2 +/, 5.43. The protonation equilibria for DHEAMP were, for H/sup +/ + L = HL/sup +/, log K = 6.92, and for H/sup +/ + HL/sup +/ = H/sub 2/L/sup 2 +/, log K = 1.16. The coordinating properties of ligands with neutral oxygen donors are discussed, and the suitability of (py)/sub 2/-18-aneN/sub 2/O/sub 4/ as a reagent for the treatment of lead poisoning is considered. The control of metal ion selectivity based on metal ion size is discussed, as well as the coordinating properties of ligands based on the 18-aneN/sub 2/O/sub 4/ ring, which have pendant donor groups attached to the nitrogens of the macrocyclic ring.

• Research Organization: Univ. of the Witwatersrand, Johannesburg, South Africa
• OSTI ID: 6996758
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 25:22; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AZINES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
COMPLEXES
DATA
ELEMENTS
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
INFORMATION
LEAD
LIGANDS
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPLEXES
PHYSICAL PROPERTIES
PYRIDINES
THERMODYNAMIC PROPERTIES