Enantiomeric bis(μ-N,N′-hexamethylenedisalicylaldiminato)-dicopper(II) complexes

The title dimeric complex, bis{mu-2,2'-[hexane-1,6-diylbis-(nitrilomethylidyne)]diphenolato-1:2kappa(4)O,N:N',O'}dicopper(II), [Cu-2(C20H22N2O2)(2)], has been investigated by single-crystal X-ray diffraction, by thermogravimetric analysis and differential scanning calorimetry, and also by FT-IR spectroscopy. Different synthetic and crystallization procedures gave crystals which were quite different in appearance, and it was initially thought that these were different polymorphic forms. Subsequent structure determination showed, in fact, serendipitous preparation of crystals in the P4(1) space group by one method and in space group P4(3) by the other. In these enantiomorphic structures, the Cu atoms have a distorted flattened tetrahedral coordination, with Cu-N and Cu-O distances in the ranges 1.954 (4)-1.983 (4) and 1.887 (4)-1.903 (4) Angstrom, respectively.