Narrow Results

The design and synthesis of new molecular hybrids composed of protoporphyrin IX (PPIX) and vitamin B₁₂ via copper catalyzed alkyne azide cycloaddition reaction is described. New, clickable aminoazide and aminoalkyne linkers were prepared and subsequently attached to PPIX (via vinyl group) and to vitamin B₁₂ giving desired building blocks. Preliminary results showed that respective water soluble hybrids were formed under CuAAC reaction. Gratifyingly, Cu incorporation into the PPIX core was avoided, which was important for further biological studies.

The synthesis and reactivity of uranium complexes supported by a bis(aryloxide) cyclam ligand are surveyed. The hemilability of this ligand proved to be particularly appropriate to stabilize highly reactive uranium(III) and uranium(IV) complexes that were able to activate different unsaturated molecules. Of note are the reductive cleavage of azobenzene with the unprecedented formation of a trans-bis(imido) uranium(VI) complex and its reaction with carbon dioxide to generate a trans-oxido-imido uranium(VI) complex and phenyl isocyanate. The formation of a trans-dioxido uranium(VI) (uranyl) complex was also observed in the reaction of uranium(IV) complexes with sodium nitrite. Quantum chemical computations and solution ¹⁵N NMR spectroscopy were employed to evaluate bond covalency in the three {E=U=E}²⁺ complexes (E = O, NR).