Molecular recognition and metal ion template synthesis.
Methods for the design and synthesis of ligands intended to be specific for a metal ion have been a recent chemical development. This article describes how this process can be inverted so that the specifics of the coordination environment around the metal ion can be used as a template in large-scale ligand synthesis. The synthesis of macrobicyclic ligands for ferric ion has been accomplished by using active esters of catechol ligands in which catecholate coordination to iron is a prelude to the organic chemical reactions that link the coordination subunits together into one ligand system surrounding a central metal ion coordination site. The lanthanide(III) ions, which are among the most labile metal ions known, have coordination numbers of 8 or higher, and thus their encapsulation into a macrobicyclic structure is a challenging problem. Lanthanide amine complexes have been used as metal templates in the synthesis of such macrobicyclic lanthanide complexes. There is evidence that such a complex is inert to exchange in aqueous solution.
McMurry
T J
TJ
Radiation Oncology Branch, National Cancer Institute, Bethesda, MD 20892.
Raymond
K N
KN
Smith
P H
PH
D002412:Cations; D055598:Chemical Phenomena; D002621:Chemistry; D007501:Iron / Q000378:metabolism; D008024:Ligands; D046911:Macromolecular Substances; D008670:Metals / Q000378:metabolism*; D008674:Metals, Rare Earth / Q000378:metabolism; D015394:Molecular Structure; D013698:Templates, Genetic
D002412:Cations; D008024:Ligands; D046911:Macromolecular Substances; D008670:Metals; D008674:Metals, Rare Earth; D007501:Iron