The unique formation of a crystal phase containing cyclic oligomers and helical polymers of the same monomeric fragment

The yellow, microcrystalline compound [Cu(pymo)] (Hpymo=2- hydroxypyrimidine) has been characterized with the newly emerging technique of ab initio X-ray powder diffraction. A unique and unprecedented crystal phase containing cyclic oligomers and infinite helical polymers (see picture) of the same monomeric fragment is selectively formed upon reaction of [Cu(CH3CN)4][BF4] and Hpymo with NEt3.