DINUCLEAR COPPER-(I) AND COPPER-(II) COMPLEXES DERIVED FROM A DIPROTONATED SCHIFF-BASE CRYPTAND

The reactions of the diprotonated Schiff-base cryptand derived from th e bicyclocondensation of tris(2-aminoethyl)amine with 2,6-diacetylpyri dine in the presence of acid and copper-(I) and -(II) tetrafluoroborat es 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 tetramine Schiff- base macrocycle in which one pyridinyl unit has been eliminated was th e product. The crystal structures of the two dinuclear complexes were determined. The Cu-I ... Cu-I separation in the cryptate complex is 6. 25 Angstrom and the Cu-II... Cu-II separation in the macrocyclic compl ex is ca. 4.6 Angstrom.