Substitution on Complexes of the Trivalent Lanthanide Ions

Ligand Substitution on Complexes of the Trivalent Lanthanide Ions 

The tripositive lanthanide ions constitute the longest range of chemically similar metal ions and in consequence provide an opportunity to study mechanistic variations as their ionic radii systematically decrease with the lanthanide contraction. However, in water in particular, the absence of direct determinations of the number of solvent molecules in the first coordination sphere of these ions has 

A La NMR study of reaction (62) is probably the first reported use of this nuclear spin in quantitative kinetic studies (2,6-dicarboxy-4-hydroxypyridine = Hdcp ). The derived rate parameters are and k (29S K) = 8 x 10 cm mol s  

As some trivalent lanthanides (Ln ) specifically displace Ca in biological systems and in consequence are used a paramagnetic probes for Ca sites in NMR studies, it is of interest to examine the relative labilities of Ca and Ln in similar coordination sites. The potentially octadentate ligand 2-[(2-bis[carboxy-methyl]amino-5-methylphenoxy)methyl]-6-methoxy-8-bis[carboxymethyl]amino- 

The decomplexation of trivalent lanthanide complexes of l,10-diaza-4,7,13,16-tetraoxacyclooctadecane-JV-acetic acid (K22MA) and l,10-diaza-4,7,13,16-tet-raoxacyclooctadecane-iV,N -di-i3-propionic acid (K22DP) (which are diaza crown ethers with one and two carboxylic acid pendant arms attached to the diaza nitrogens, respectively) has been studied by a spectrophotometric SF method, and is characterized by the rate law (64). When the diaza crown ether is K22MA, fcd = 0.88, 0.25, and 3.99 s respectively, for La , Eu, and Lu and -1.42 X lO and 4.93 x 10 dm moP s for La and Eu and when the diaza 

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