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Polycyclic tetraazamacrocycles
Plutnar, Jan ; Hermann, Petr (advisor) ; Podlaha, Jaroslav (referee) ; Růžička, Aleš (referee)
Two series of new bicyclic tetraazamacrorycles built up on skeletons of either 1,5,8,12-tetraazabiryclo[10.2.2]hexadecane (1,4-en-cyclam) I or 1,4,8,11- tetraazabicyclo[6.6.2]hexadecane (1,8-en-ryclam) 8 were prepared. The 1,4- en.cyc|am-based unsymmetrica| compounds bearing the pnitrobenzy| moieý (precursor for a biomolecule-conjugation) were synthesised exploiting the low so|ubi|iý of the intermediate quaternary derivative 2 in non-po|ar so|vents. The |igands 3 and 6 exhibited the expeďed comp|exing abi|ity towards copper(Il) and zinc(Il) although the complexation proceeded relatively slowly (at room temperature in order of hours). The mďa| comp|exes thus formed exhibited thermodynamic stability constants lower than those repofted for similar monoryclic tetraazamacrocycles (cyclam, Me+cyclam) probably due to inadvisability of the conformational change (chair or twisted-boat -> boat conformation of the piperazine subunit) conneďed to the metaI ion encapsulation. On the other hand, when the stability of coppe(Il) complex of 3 is compared to stabi|iý constant reported for the biryc|ic amine 1, the trend in the values of these constants is the same for the couple ligand I - ligand 3 as for the couple cyclam - Me+cyclam. During the attempted synthesis of the monoacetate ligand 5a an unusual reaction behaviour...
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