Calix[4]arene-Analogous Technetium Supramolecules.

Calix[4]arene-analogous technetium supramolecules (1 and 2) were assembled using (NBu4)[Tc2(µ-Cl)3(CO)6] and neutral flexible bidentate nitrogen-donor ligands (L1 and 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. These supramolecules are the first example of fac-[Tc(CO)3]+ core-based metallocalix[4]arenes and second example of fac-[Tc(CO)3]+ core-based metallomacrocycles. Structurally similar fac-[Re(CO)3]+ core-based macrocycles (3 and 4) were also prepared using [Re(CO)5X] (where X = Cl or Br) and L1 or L2. The products were characterized spectroscopically and by X-ray analysis.