Part I Synthesis, functionalization and metal complexation of polyamine macrocycles Part II Synthesis and dynamic NMR studies of bicyclic ureas

Part I. The syntheses and characterizations of novel bicyclic tetraamines (shown below) have been accomplished. The complexation of bicyclic tetraamines (R = CH$\sb3)$ with Li$\sp+$ and Na$\sp+$ have been studied by NMR spectroscopy. These tetraamines are strong bases and selective Li$\sp+$ binders. The parent cross-bridged cyclam (R = H; X = Y = CH$\sb2)$ was functionalized with a variety of ligating groups containing heteroatoms. Several of the ligands were investigated as possible radiopharmaceutical ($\rm\sp{99m}Tc$) imaging agent precursors. Syntheses of non-adjacent selectively functionalized tetraazacycloalkanes have also been developed. Part II. Synthesis and dynamic NMR studies of intramolecular transamidation of bicyclic urea 99 have been carried out. Bicyclic urea 99 exhibited dynamic exchange broadening indicative of an enantiomerization process in D$\sb2$O at pD $\u3e$ 8. Below pD 8 bicyclic urea converts to guanidinium salt 16. Semiempirical methods (AM1, PM3) were used to study possible intermediates of the transamidation reaction.* ftn*Please refer to the dissertation for diagrams