Lay summary

Technetium is an important element for society. Its long-lived isotope technetium-99 (99Tc) is a fission product in nuclear power plants (production worldwide ca. 3000 kg / year) and a challenging task for nuclear waste management, due to its long half-life (2.13ยท105 years). Furthermore, the meta-stable nuclear isomer 99mTc is a common radio tracer for nuclear medical diagnostics. The availability of this nuclear isomer from generators, in combination with the short physical half-life time (6 h) and the emission of low energy gamma-rays (140.5 keV) make 99mTc a very convenient and practical isotope. To pave the way for new opportunities in 99mTc radio probe design and to generate new impulses for technetium chemistry in general, the field of water stable fac-{99(m)TcO3}+ complexes has been developed. The reactivity of fac-{99(m)TcO3}+ complexes with alkenes (vicinal cis-dihydroxylation reaction by (3+2)-cycloaddition) plays a central role in this novel technetium chemistry. This project develops the chemistry of {99(m)TcO3}+ compounds further and aims at the advancement of this chemistry from the level of fundamental research to utilization.

An important issue for the development of labeling procedures which are based on the reactivity of fac-{99mTcO3}+ complexes with alkenes is the control of the stereo-chemistry of the (3+2)-cycloaddition reaction. The project will give detailed insights about factors which influence the stereo-chemistry of the (3+2)-cycloaddition and will lead to reactions, which are under full stereo-control. Furthermore, the reactivity and stability of (3+2)-cycloaddition products, which carry an additional functional group to the glycolato unit will be studied. Finally, to widen the scope for the development of new imaging probes a nanoplatform suitable for molecular imaging will be realized.