ISSN:
1434-193X
Keywords:
Macrobicycles
;
Macrotricycles
;
Tetraazacycloalkanes
;
Protonation
;
Molecular modelling
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A versatile synthesis of spherical macrobicyclic and cylindrical macrotricyclic ligands is described using 1,4,8,11-tetraazacyclotetradecane (cyclam), 1,4,7,10-tetraazacyclododecane (cyclen), or dioxo macrocycles as precursors. Macrobicycles have been obtained by allowing cyclam, cyclen, or 5,12-dioxocyclam (1,4,8,11-tetraazacyclotetradecane-5,12-dione) to react with a bis-electrophilic spacer under high dilution conditions. A surprising selectivity has been observed for 2,6-dioxocyclen (1,4,7,10-tetraazacyclododecane-2,6-dione), which yields only macrotricycles under the same reaction conditions. Molecular modelling studies have been carried out to investigate the selectivity of the reactions, and good agreement has been observed between the theoretical predictions and experimental data. 1D- and 2D-NMR studies reveal a highly rigid structure in the case of macrobicycles. The macropolycyclic ligands show very different basicities, which demonstrates the influence of the cross-linker on the coordination properties of the ligands.
Type of Medium:
Electronic Resource
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