Macrocyclic polyfunctional Lewis bases. XI: Structure of trichlorocuprates of Crown-complexed sodium

Abstract The structures of trichlorocuprates of benzo-15-crown-5 complexed sodium and dibenzo-18-crown-6 complexed sodium were determined from diffractometer data by direct methods and refined by least-squares to R(F) = 0.059 and 0.039 respectively. Both complexes, (C 14 H 20 O 5 ) 2 Na 2 Cu 2 Cl 6 and(C 20 H 24 O 6 ) 2 Na 2 Cu 2 Cl 6 , are centrosymmetric and consist of very similar Cu 2 Cl 6 2− units lying across the centre of symmetry. Two Na + cations, surrounded individually by crown ether ligands, are located on opposite sides of the anion. The dimeric structure of the anion is very characteristics for chlorocuprates of very bulky cations and resembles the anions present in tetraphenylphosphonium and tetraphenylarsonium chlorocuprates. This gives a further supportto the «super heavy” alkali metal cations concept.