A strategy for the synthesis of phosphorus-containing macrocycles-ligands for exceptional coordination geometries

The shape of rings to come! The novel synthetic strategy for macrocycles containing differently functionalized ligands is based on a coupling reaction between two alkali-metal-fixed carbanionic centers I and two specifically connected, electrophilic phosphorus centers II (see scheme, Do=donor atom). Twofold P - C-bond formation first results in a metallamacrocycle III, which is subsequently converted by protonation into the neutral ring system IV. The formation of unprecedented coordination geometries of CuI and Ni0 centers is shown by the X-ray crystal structures of the complexes V.