Towards highly stable complexes of copper radionuclides with bispidines

Bispidines (bispidine = 3,7-diazabicyclo[3.3.1]-nonane) show interesting complexation behaviour towards transition metal ions. [1] The stabilities achieved for copper complexes with bispidines – lying in the same range as found for copper complexes of aza macrocycles – offer the possibility to apply such complexes for diagnostic and therapeutic purposes (^64/67Cu).
We want to present the synthesis of novel hexadentate bispidine derivatives having pyridine and/or imidazole units as donor groups. Cu(II) complexes of some bispidines have been isolated and the structures were characterised by single-crystal X-ray diffraction analysis. Studies which have been performed to label selected bispidines with ^64/67Cu indicate a rapid formation of stable complexes under mild conditions. Chemical approaches to introduce bio-molecules into the bispidine skeleton are discussed.