Dinuclear copper-(I) and -(II) complexes derived from a diprotonated Schiff-base cryptand

The reactions of the diprotonated Schiff-base cryptand derived from the bicyclocondensation of tris(2-aminoethyl)amine with 2,6-diacetylpyridine in the presence of acid and copper-(I) and -(II) tetrafluoroborates have been studied. In the former reaction a homodinuclear copper(I) complex of the neutral cryptand was recovered whereas in the latter a homodinuclear copper(II) complex of the bibracchial tetraimine Schiff-base macrocycle in which one pyridinyl unit has been eliminated was the product. The crystal structures of the two dinuclear complexes were determined. The Cu I · · · Cu I separation in the cryptate complex is 6.25 Å and the Cu II · · · Cu II separation in the macrocyclic complex is ca. 4.6 Å.