Equilibria and dissociation kinetics of lanthanide complexes of diaza crown ether carboxylic acids

Journal Article · Wed Oct 19 04:00:00 EDT 1988 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00294a023· OSTI ID:6299056

Chang, C A; Chang, P H.L.; Manchanda, V K; Kasprzyk, S P

The equilibria and dissociation kinetics of lanthanide and several transition-metal and Pb(II) complexes of some diaza crown ether carboxylic acids are studied. The ligands are K22MA (1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N-acetic acid), K22DP (1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-di-..beta..-propionic acid), and K22MP (1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N-..beta..-propionic acid). The protonation constants of these ligands are similar to those of the structural analogues and are in the range log K/sub 1/ = 8.80-9.01 and log K/sub 2/ = 7.26-8.16. The stability constants are all lower than that of their structural analogue K22DA (1,10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N'-diacetic acid) due to the reduction of the chelate effect or an unfavorable steric effect or both. The kinetic dissociation rates are all faster as compared to those of K22DA complexes. Acid-dependent (k/sub H/) and acid-independent (k/sub d/) rate constants are obtained by the measurement of rates at various pH values, and they correlate inversely with the values of stability constants. 15 references, 1 figure, 4 tables.

• Research Organization: Univ. of Texas, El Paso (USA)
• DOE Contract Number: FG05-84ER13292
• OSTI ID: 6299056
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 27:21; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
CARBOXYLIC ACIDS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMPLEXES
DATA
EXPERIMENTAL DATA
GLYCOLS
HETEROCYCLIC COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
KINETICS
LEAD COMPLEXES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC POLYMERS
POLYETHYLENE GLYCOLS
POLYMERS
RARE EARTH COMPLEXES
REACTION KINETICS