Calix[4]arene-Analogous Technetium Supramolecules br

Calix[4]arene-analogous technetium supramolecules (1and2) were assembled using (NBu4)[Tc2(mu-Cl)3(CO)6] andneutralflexible bidentate nitrogen-donor ligands (L1and L2) consisting of four arene units covalently joined via methylene units.The neutral homoleptic technetium macrocycles adopt a partial cone/cone-shaped conformation in the solid state. Thesesupramolecules are thefirst example offac-[Tc(CO)3]+core-based metallocalix[4]arenes and second example offac-[Tc(CO)3]+core-based metallomacrocycles. Structurally similarfac-[Re(CO)3]+core-based macrocycles (3and4) were also prepared using[Re(CO)5X] (where X = Cl or Br) and L1or L2. The products were characterized spectroscopically and by X-ray analysis.